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UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY

Volume 17, No. 14, pp. 579-611, 1 fig.
April 24, 1968



Summer Birds From the Yucatan Peninsula, Mexico


BY

ERWIN E. KLAAS


UNIVERSITY OF KANSAS
LAWRENCE
1968




UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Frank B. Cross, J. Knox Jones, Jr.


Volume 17, No. 14, pp. 579-611, 1 Fig.
Published April 24, 1968


UNIVERSITY OF KANSAS
Lawrence, Kansas


PRINTED BY
ROBERT R. (BOB) SANDERS, STATE PRINTER
TOPEKA, KANSAS

1968




Transcriber's Note: Irregularities and inconsistencies in the text have
been retained as printed.




Summer Birds From the Yucatan Peninsula, Mexico

BY

ERWIN E. KLAAS




INTRODUCTION


Because its unique geographical location and ecological setting
supports a rich and varied avifauna, the Yucatán Peninsula has received
considerable attention by ornithologists. The most valuable
contribution is Paynter's "The Ornithogeography of the Yucatán
Peninsula" (1955a), an authoritative study of the composition,
distribution, and origin of the avifauna of the region. His work
contains a complete listing of all species reported to that time from
the peninsula. It considers the hundreds of specimens collected by the
author and his associates during many months of field work, provides a
synthesis of all the information available to 1955, and is the basic
reference to the avifauna of the area. Paynter also pointed out matters
for which information is lacking. Two of the most conspicuous deficits
that he noted are the lack of knowledge about many species that occur
on the peninsula in summer, and the paucity of data as to time of
breeding, although some information on reproduction in a few species
was published subsequently by Paynter (1955b) and Storer (1961).

In July and August of 1962, I was a member of a field party from the
Museum of Natural History, The University of Kansas, engaged in a
survey of vertebrates and their ectoparasites on the Yucatán Peninsula.
The purpose of the present paper is to report on the birds collected
and observed during the course of this field work. Particular emphasis
is given to breeding information, but observations concerning
distribution, incidence, and molt also are given. In addition, a list
of the chewing lice (Mallophaga) taken from various specimens is given
in Table 2 and in the appropriate species account of the host. Other
ectoparasites removed from these birds will be reported on elsewhere.




ACKNOWLEDGMENTS


I am especially indebted to Dr. J. Knox Jones, Jr., under whose
direction this field study was undertaken, and to Dr. Richard F.
Johnston who aided greatly in the identification of specimens and
critical reading of the manuscript. I am grateful also to other members
of the field party who helped in collecting many of the specimens
reported herein: Ticul Alvarez, A. Binion Amerson, Dr. William E.
Duellman, Dr. J. Knox Jones, Jr., Thomas E. Lovejoy, III, Jack G.
Makepeace, Dwight R. Platt, William C. Stanley, Jerome B. Tulecke, and
John Wellman. Dr. K. C. Emerson graciously identified the specimens of
Mallophaga and Dr. Allan R. Phillips aided in identification of some of
the birds.

In addition, I wish to express sincere thanks for quarters provided our
field party at the Campo Experimental Forestal "El Tormento" at
Escárcega, Campeche, by Ing. Hector Flores S.; at Pueblo Nuevo X-can,
Quintana Roo, by Pablo Alimilla; at Felipe Carrillo Puerto, Quintana
Roo, by Fernando Esquival Montono; and at Pisté, Yucatán, by Luis V.
Polanco. The field party benefited also from arrangements and helpful
suggestions made by Eduardo C. Welling of Mérida and Marynoll Father
Joseph Early of Felipe Carrillo Puerto. Wherever we camped the local
Mayans were exceptionally helpful, especially as guides and collectors.

Our field party was composed of two units. One unit, working on a
survey of Middle American vertebrates and their ectoparasites, was
supported by the United States Army Medical Research and Development
Command (Contract No. DA-49-193-MD-2215). The second unit, composed of
students in the Field Course in Vertebrate Zoology from The University
of Kansas, was supported in part by the Museum of Natural History and
by a grant from the National Science Foundation (G 20939, Special
Projects in Science Education). The late Ing. Luis Macías Arellano,
Departamento de la Fauna Silvestre, Dirección General de Caza, México,
D.F., generously provided the necessary permits for collecting
vertebrates.




PHYSICAL FEATURES


The Yucatán Peninsula is a northeastern projection of Central America
lying between the Gulf of Campeche, the Gulf of Mexico, and the
Caribbean Sea. Its area is approximately 143,500 square kilometers and
includes the Mexican states of Campeche and Yucatán and the sparsely
settled Territory of Quintana Roo, plus parts of British Honduras and
the Petén region of Guatamala. The peninsula has a mean breadth of
about 300 kilometers and a coast line of about 1100 kilometers.

Topographically, the peninsula is a low-level plain that rises
gradually inland to the south. The coast on the north and west is low,
sandy, and semi-barren; openings through the outer coastal strand lead
to narrow brackish lagoons surrounded by mangroves. The eastern coast
consists of bluffs, indented with bays and bordered by several islands,
the largest being Cozumel. A small range of hills traverses the
peninsula from the city of Campeche to Chetumal Bay; although appearing
sizeable, these almost nowhere exceed 100 meters in elevation. The
extreme southerly portion of the peninsula is moderately hilly and is
covered with tropical rain forest.

The peninsula is composed almost wholly of a bed of coraline and porous
limestone covered with a layer of thin, dry soil formed from the slow
weathering of the bedrock. The humus is rarely more than a few
centimeters deep, and consequently cornfields (_milpas_) must be moved
every two or three years. With each move a new area of the land is
cleared and burned. This agricultural practice has been routine with
the Mayan people for centuries and apparently has had a profound effect
on the vegetation, severely limiting the extent of virgin forest.

In many places, especially in the northern part of the peninsula, the
rocky surface of the terrain is perforated by natural wells or
sink-holes, which are called _cenotes_ locally. Many _cenotes_ support
small "islands" of unique vegetation, the composition of which somewhat
resembles the rain forest of the southern part of the peninsula.
Temporary water-holes and shallow lakes (_aguadas_) are sparsely
scattered throughout the southern half of the peninsula. There are no
rivers of importance; most that are present are in the southernmost
region.

The climate of northern Yucatán is hot and dry, and the absence of high
mountainous ridges to intercept the moisture-bearing clouds from the
Atlantic accounts for less rain than would be expected. The
southernmost part of the peninsula receives a maximum of 200
centimeters of rain annually. The amount decreases toward the north to
an average of about 45 centimeters. Almost all of the rain falls from
May to October. Daily temperatures range from 78° to 98° F. in the
shade; cool sea winds prevail day and night throughout most of the
year. The hottest months are May and June. In winter, fierce northers,
_temporales_ or _nortes_, occasionally sweep across this open region,
bringing rain and cooler temperatures, lasting several days.

The areas adjacent to British Honduras and Guatemala receive sufficient
rainfall to support forests containing mahogany (_Swietenia_);
sapodilly (_Achras_); several valuable cabinet woods; logwood
(_Haematozylon_) and other dyewoods. As one proceeds northward the
flora and fauna change gradually from that of the wet tropics to that
of the dry tropics.

Paynter's (1955a) system of vegetational zones on the peninsula is
useful to ornithologists. He recognized three zones: Scrub, Deciduous
Forest, and Rain Forest. The Scrub zone occupies Isla Holbox and Isla
Mujeres and the arid northern coast of Yucatán. The zone extends only a
few miles inland and consists of low-tropical thorn forest of mesquite
(_Prosopsis_), _Mimosa_, _Yucca_, _Agave_, and mangrove (_Rhizophora_)
wherever standing water occurs. Sisal in Yucatán and Isla Mujeres of
Quintana Roo are in this Scrub zone.

The Deciduous Forest zone is a vast area of low, semiarid, secondary
forest occupying all of the state of Yucatán not in the Scrub zone,
northern Campeche, and a thin strip a few kilometers wide in Quintana
Roo along the Yucatán-Quintana Roo border and a similar narrow band
along the eastern coast. The island of Cozumel is also included in this
zone. Collections were made in the Deciduous Forest at Champotón,
Campeche, Isla Cozumel and Puerto Juárez, Quintana Roo, and Pisté,
Yucatán.

The Rain Forest zone occupies the remainder of the peninsula and
includes most of the territory of Quintana Roo, and the southern half
of Campeche. Collections were made in this zone at Escárcega, Campeche,
and at Felipe Carrillo Puerto and Pueblo Nuevo X-can, Quintana Roo.
Isla del Carmen cannot be accurately assigned to any of these three
zones because most of the island has been planted in coconut palms. It
is an area of high rainfall and may once have supported rainforest.

In the present report the term "second growth" refers to areas that
have been recently cut over. In these areas, the forest is
characteristically low and in a stage of transition. In the Rain Forest
zone "second growth" areas usually contain species of deciduous trees.

Paynter (1955a) has given an excellent descriptive summary of the
topography, climate, and phytogeography of the Yucatán Peninsula and
there is little need to go into further detail here. During summer, the
rainy season, the Deciduous Forest is much more luxuriant in appearance
than in winter when most of the trees have lost their leaves. Also, the
numerous _cenotes_ in this zone support a limited growth of evergreen
trees. For example, the large Cenote Seco about two kilometers east of
Chichén-Itzá contains elephant ear (_Caladium_), mamey (_Mammea_), figs
(_Ficus_), and other large trees the trunks of which are some 10 meters
below the surface of the surrounding tableland. These plants project
five to 10 meters above the surrounding low forest. The floor of this
_cenote_ is near the watertable but not below it.




GAZETTEER


The specimens of birds reported herein were collected at the localities
shown on the accompanying map (Fig. 1). These localities are listed
below in alphabetical order according to states.


    Campeche

    Champotón.--Lat. 19° 21´ N, long. 90° 43´ W, sea level to five
    meters. A fishing village on the Gulf of Mexico. Collections were
    made principally at our camp five kilometers south of the town. Low
    deciduous forest, second growth, and _milpas_.

    Escárcega.--Lat. 18° 37´ N, long. 90° 44´ W, elevation 65 meters. A
    village in southwestern Campeche. Field work was carried out
    principally in the vicinity of an agricultural experiment station
    seven and a half kilometers west of the town. Second growth and
    moderately tall rainforest.

    Isla del Carmen.--Lat. 18° 43´ N, long. 91° 41´ W, sea level to two
    meters. An island in the mouth of Laguna de Términos. Collections
    were made at our camp on the northeastern end of the island, about
    one kilometer southwest of Puerto Real. Coconut plantations and
    mangrove swamp.


    Quintana Roo

    Felipe Carillo Puerto.--Lat. 19° 35´ N, long. 88° 02´ W, elevation
    30 meters. A village in east-central Quintana Roo. Field work was
    centered at Rancho San Miguel, about four kilometers north-northeast
    of the village. Mostly second growth rainforest with scattered
    large patches of tall trees (to 30 meters). Several large _milpas_
    were present on the ranch some of which had been recently cleared.
    Our camp was at a large aguada bordered on one side by an extensive
    marsh with tall dense grass.

    Isla Cozumel.--Lat. 20° 27´ N, long. 86° 26´ W, sea level to 10
    meters. A large island, 15 kilometers east of the mainland.
    Collections were made on the northwestern part of the island from
    one to five kilometers north-northeast of the village of San Miguel
    in low, dense deciduous forest.

    Isla Mujeres.--Lat. 21° 12´ N, long. 86° 43´ W, sea level to 30
    meters. A small, narrow island about eight kilometers from the
    coast at the northeastern end of the peninsula. Field work was done
    on the beach at the northern end of the island, in low deciduous
    forest in the middle of the island, and in low deciduous forest and
    cactus (_Opuntia_) association on a high rocky bluff on the
    southern end of the island.

[Illustration: FIG. 1. A map of the Yucatán Peninsula of
Mexico showing localities referred to in the text.]

    Pueblo Nuevo X-can.--Lat. 21° 52´ N, long. 87° 26´ W, elevation 10
    meters. A village five kilometers east of X-can, Yucatán, in
    rainforest with dense underbrush. Specimens were obtained from the
    immediate vicinity of the village.

    Puerto Juárez.--Lat. 21° 10´ N, long. 86° 49´ W, sea level. A small
    port on the Caribbean Coast with alternating sand beach and
    limestone shore. Mangrove swamps extend a short distance inland at
    various points. Specimens were collected in rainforestlike
    vegetation at a small _cenote_, in low deciduous forest, and at our
    camp along a large, cleared airstrip four kilometers west-southwest
    of the village.


    Yucatán

    Pisté.--Lat. 20° 42´ N, long. 88° 28´ W, elevation 10 meters. A
    village in dense, low deciduous forest with many nearby _milpas_.
    Collections were made in a wide area in the vicinity of the
    village, including nearby Chichén-Itzá.

    Sisal.--Lat. 21° 10´ N, long. 90° 00´ W, sea level. A small village
    on the north-western coast of the peninsula. Collections were made
    on the beach, in the low scrub vegetation behind the beach, and in
    the mangrove swamps and nearly-dry lagoons further inland, from
    three to 13 kilometers west-southwest of the village.




ANNOTATED LIST OF SPECIES


Catalogue numbers in the following accounts are those of the Museum of
Natural History, The University of Kansas. With the exception of a
synoptic collection presented to the Departamento de la Fauna
Silvestre, Dirección General de Caza, México, D.F., all of the
specimens mentioned are in the museum at the University of Kansas.

Unless otherwise indicated, specimens taken were not molting. For birds
undergoing postnuptial or postjuvenal molt, the degree of advancement
of the molt is indicated by the numbers of primaries and rectrices that
are new or partly ensheathed. Information on the condition of the
testes refers to the left testis unless otherwise noted.

Scientific and vernacular names follow Friedmann _et al._ (1950) and
Miller _et al._ (1957) except for specimens of species or genera that
have been more thoroughly treated systematically since the publication
of the Mexican Checklist, for example, _Columbina_, _Centurus_ and
_Platypsaris_, by Johnston (1962), Selander and Giller (1963), and
Webster (1963), respectively. The trinomial is used whenever
subspecific identities could be made with a reasonable degree of
certainty. The specimens of several kinds were in extremely worn
plumage or in molt and meaningful judgments concerning such characters
as relative darkness or paleness of plumages could not be made.

Specimens are listed in each account according to the temporal order in
which they were collected.

_Bulbulcus ibis_ Linnaeus: Cattle Egret.--Our specimen is one of three
individuals seen feeding near cattle at Rancho San Miguel on August 13
and 14.

    Specimen (1): [Male], 40401, testis 6 x 2 mm., 289.5 gm. (August
    14), 4 km. NNE Felipe Carrillo Puerto.

_Casmerodius albus_ (Linnaeus): American Egret.--We took one egret from
a flock of about 20 that flew low over our campsite on the morning of
July 12.

    Specimen (1): [Female], 40402, ovary inactive, 10 x 5 mm., 607.5
    gm. (July 12), 5 km. S Champotón. Mallophaga: _Ciconiphilus
    obscurus._

_Cochlearius cochlearius_ (Linnaeus): Boat-billed Heron.--Three
individuals were seen on a small point of land immediately south of the
village on the west coast of Isla Mujeres on the afternoon of August 1.
One was foraging in a small cove about one mile south of the village on
the morning of August 2. Paynter (1955a) did not list the species for
Isla Mujeres; our observations seem to constitute the first records for
the island.

_Mycteria americana_ Linnaeus: Wood Ibis.--A flock of about 15 flew
over our camp 4 km. NNE Felipe Carrillo Puerto on August 14.

_Sarcoramphus papa_ (Linnaeus): King Vulture.--Our specimen was one of
two individuals seen at a cenote.

    Specimen (1): [Male] 40403, testes inactive, 8 lbs. (July 29), 1
    km. N Pueblo Nuévo X-can. Mallophaga: _Colpocephalum megalops_.

_Carthartes burrovianus_ Cassin: Yellow-headed Vulture.--We saw several
Yellow-headed Vultures on Isla del Carmen on July 6, 7, 8, and 9. _C.
burrovianus_ was more abundant than either _Carthartes aura_ or
_Coragyps atratus_ in the vicinity of Champotón, where we confirmed
field identifications by taking a specimen. Until Wetmore (1950)
clarified the status of _C. burrovianus_ in southern Mexico and Central
America, the species had gone unnoticed or misidentified as _C. aura_.
The Mexican Checklist (Friedmann, Griscom, and Moore, 1950) omitted _C.
burrovianus_ from the avifauna of México. Blake (1953) included
Tabasco, Chiapas, and Veracruz within the range of the species, but
Paynter (1955a) omitted it from his list of birds of the Yucatán
Peninsula. Our specimen seemingly constitutes the first record from the
peninsula.

    Specimen (1): [Male], 40404, testes inactive, 1-3/4 lb. (July 9), 2
    km. S Champotón.

_Chondrohierax uncinatus uncinatus_ (Temminck): Hook-billed Kite.--A
pair was seen 5 km. S Champotón on July 8 and 9. Both birds were in
adult plumage and appeared to be mated, although we found no nest. The
male is referable to _C. u. uncinatus_ on the basis of the narrow white
ventral bands, most of which are 0.3 millimeter or less in width. None
of the bars exceeds 0.5 millimeter in width. Paynter (1955a) discussed
in detail the contradictions in the literature concerning the
geographic range of this subspecies, and referred a male in his
collection taken in February, 1952, to _C. u. aliquonis_. Traylor
(1941) collected a large series of this species in Yucatán and Campeche
in winter and allocated the specimens to the nominate form.

At Pisté, on July 23, a nestling approximately half-grown was brought
in by a local boy. The rectrices were partly ensheathed and the feather
count extensively downy.

    Specimens (2): [Male], 40406, testis 9 × 5 mm., 215.0 gm. (July
    10), 5 km. S Champotón; [Male], 40405, nestling, 117.6 gm. (July
    24), Pisté.

_Buteo magnirostris gracilis_ (Ridgway): Roadside Hawk.--This was the
only hawk seen on Isla Cozumel.

    Specimens (2): [Male], 40411, testis 5 mm., 207.3 gm. (August 10),
    4 km. N San Miguel; [Female], 40412, 242 gm. (August 10), 3-1/2 km.
    N San Miguel.

_Buteo magnirostris conspectus_ (Peters): Roadside Hawk.--This species
was the commonest hawk on the peninsula and was seen at all localities
except Isla Mujeres and Sisal.

    Specimens (5): [Male], 40409 (July 12), and [Female], 40410, ova to
    1 mm., 249 gm. (July 16), 7-1/2 km. W Escárcega; [Male], 40413, 279
    gm. (July 17) 1 km. N, 13 km. W Escárcega; [Male], 40407, testis 5
    × 2 mm., 254.7 gm. (July 23), Pisté: [Female], 40408, ovary
    inactive, 279.0 gm. (July 28), Pueblo Nuevo X-can.

_Buteo brachyurus_ Vieillot: Short-tailed Hawk.--Our one specimen, a
male (40414) weighing 342 gm. and in white-bellied phase, was taken by
a native 6 km. W Escárcega on July 14. The testes were inactive.

_Buteo nitidus plagiatus_ (Schlegel): Gray Hawk.--Our specimen is one
of two subadults sighted near a large milpas, on Rancho San Miguel.

    Specimen (1): [Male], 40415, testis 5 × 3 mm., 364 gm. (August 15),
    4 km. NNE Felipe Carillo Puerto. Mallophaga: _Craspedorrhy_ sp.

_Buteogallus anthracinus_ (Lichtenstein): Common Black Hawk.--Five
individuals were seen on August 23 along a stretch of five miles of
highway about 30 mi. SW Champotón, Campeche. The species was identified
from the description given in Blake (1953). The hawks were perched on
dead limbs in full view, 50 to 100 feet from the highway, which at this
locality parallels the beach, sometimes only a few yards from the
water.

_Ortalis vetula intermedia_ Peters: Chachalaca.--Chachalacas were heard
or seen at all localities on the mainland except Sisal.

Specimens (3): [Female], 40416, 423 gm. (July 13), [Female], 40417, 432
gm. (July 15), and [Female], 40418, ovary 12 × 9 mm., 408.5 gm. (July
16), 7-1/2 km. W Escárcega. Mallophaga: _Amyrisidea spicula_, July 16.

_Colinus nigrogularis persiccus_ Van Tyne and Trautman: Black-throated
Quail.--These quail were abundant in the arid scrub west of Sisal.
Several coveys of half-grown chicks were seen and specimens taken were
in full breeding condition. On a two-mile walk on August 18, in the
coastal scrub about 5 km. W Sisal, a pair of quail was seen about every
100 paces.

    Specimens (4): [Female], 40422, ovum in oviduct 30 x 22 mm., 147.5
    gm. (August 10), [Female], 40420, ovum in oviduct 27 mm., 151.7 gm.
    (August 18), [Male], 40421, testis 9 × 5 mm., 119.6 gm. (August
    18), and [Male], 40419, testis 11 × 6 mm., 145.7 gm. (August 18),
    all from southwest of Sisal.

_Laterallus ruber_ (Sclater and Salvin): Little Red Rail.--Two
specimens were taken about 3-1/2 km. N San Miguel, Isla Cozumel, in
tall grass. One bird was shot when flushed; the other was caught in a
Museum Special mousetrap. I follow Brodkorb (1943) and Paynter (1955a)
who did not recognize subspecies in this species.

    Specimens (2): [Female], 40424, ovary 9 × 3 mm., 41.5 gm. (August
    8), and [Male], 40423, testis 6 mm., 40.0 gm. (August 11), Isla
    Cozumel.

_Porphyrula nartinica_ (Linnaeus): Purple Gallinule.--A female was
taken in the tall grass where red rails were found on Isla Cozumel.

    Specimen (1): [Female], 4025, ovary 14 x 7 mm., 169 gm. (August
    10), 3-1/2 km. N San Miguel.

_Haematopus ostralegus_ Linnaeus: Oyster-catcher.--Two individuals were
seen along the beach about 6 km. W Sisal on August 10 and 11.

_Charadrius alexandrinus tenuirostris_ (Lawrence): Snowy Plover.--This
was one of the commonest shorebirds on the beaches and mudflats west of
Sisal. Several immature birds were taken, along with a pair of
half-grown chicks, indicating the species was breeding, or recently had
bred, there. No previous record of this species breeding on the
peninsula has been found.

    Specimens (6): [Female], 40431, ovary inactive, 38.2 gm. (August
    7), 4 mi. S Sisal; [Male], 40426 testis minute, 35.4 gm. (August
    9), [Female], 40427, half-grown chick, 25.4 gm. (August 9), [Male],
    40428, half-grown chick, 21.2 gm. (August 9), [Female], 40430,
    imm., 38.0 gm., little fat (August 10), [Female], 40429, ovary
    inactive, 35.7 gm., little fat, molting--1st through 6th primaries
    and middle pair of rectrices are new (August 10), all from 13 km.
    WSW Sisal. Mallophaga: _Actornithophilus ochraceus_, August 9;
    _Quadraceps assimilis major_, August 7.

_Charadrius wilsonia wilsonia_ Ord: Wilson Plover.--A flock of about 11
was seen on the beach north of the village on Isla Mujeres on August 1.
Two specimens were collected on the leeward side of the island about
three kilometers south of the village on August 2. The only evidence of
breeding was slightly enlarged testes in one male. Two individuals were
sighted on the east coast of the mainland at Puerto Juarez on August 4.
The species was common 3 to 13 km. west-southwest of Sisal; specimens
taken there may have been migrants.

    Specimens (5): [Male], 40435, testis 3 × 1 mm., 59.0 gm. (August
    2), and [Female], 40436, ovary inactive, 49.3 gm. (August 2), Isla
    Mujeres; [Female], 40434, ovary inactive, 53.6 gm. (August 7),
    [Male], 40433, testis 1 mm., 54.5 gm. (August 9), and [Male],
    40432, imm., 53.7 gm., little fat (August 11), 3-13 km. WSW Sisal.
    Mallophaga: _Quadraceps assimilis major_, August 2 and August 11.

_Actitis macularia_ (Linnaeus): Spotted Sandpiper.--A total of six
individuals was seen on Isla Mujeres; each was alone. The species was
common at Sisal where it was often seen in small mixed flocks with
Snowy Plovers and Wilson Plovers.

    Specimens (3): [Male], 40437, testis 2 × 1 mm., 33.8 gm. (August
    9), [Male], 40438, imm., 28.2 gm. (August 10), and sex? 40439,
    imm., 31.0 gm. (August 10), 13 km. WSW Sisal. Mallophaga:
    _Quadraceps ravus_; August 10.

_Catoptrophorus semipalmatus inornatus_ (Brewster): Willet.--A flock of
15 or 20 individuals was seen almost every day of our stay on the beach
8-13 km. WSW of Sisal. Measurements of two of the specimens are large
and they are clearly referable to _C. s. inornatus_.

    Specimens (3): [Male], 40441, testis 3 mm., 242.3 gm., wing 205
    mm., tail 80 mm., tarsus 66 mm., culmen (from feathers) 60 mm.
    (August 9), [Female], 40440, ovary inactive, 240.5 gm., wing 204
    mm., tail 77 mm., tarsus 69 mm., culmen (from feathers) 59 mm.
    (August 11), and [Male], 40442, imm., 221.1 gm. (August 11) 8-13
    km. WSW Sisal. Mallophaga: _Austrominopon sachlebeni_, August 9;
    _Quadraceps carrikeri_, August 11.

_Arenaria interpres_ (Linnaeus): Turnstone.--Six individuals were
sighted on Isla Mujeres on August 1 and one individual was sighted 4
km. W Sisal on August 11.

_Crocethia alba_ (Pallas): Sanderling.--This species was relatively
common at Sisal where several flocks of 30 to 40 birds were seen. One
specimen (40444) shows an unusual pattern of molt; replacement of outer
primaries has preceded that of the inner.

    Specimens (4): [Male], 40445, testis 3 × 1 mm., 57.5 gm., heavy fat
    (August 9), [Female], 40444, ovary granular 6 × 3 mm., 56.7 gm.,
    molting (August 11), [Male], 40443, 35.5 gm. (August 11), and
    [Female], 40446, imm., 54.1 gm. (August 11), 6-1/2-13 km. WSW
    Sisal. Mallophaga: _Lunaceps holophaeus actophilus_, August 11;
    _Carduiceps zonarius_, August 11.

_Ereunetes pusillus_ (Linnaeus): Semipalmated Sandpiper.--The only
individual seen was taken from a mixed flock of Sanderlings and Wilson
Plovers.

    Specimen (1): [Male], 40447, testis minute, 24.4 gm. (August 11), 8
    km. WSW Sisal.

_Himantopus mexicanus_ (Müller): Black-necked Stilt.--A lone individual
was sighted on Isla Mujeres on August 2. A pair was on the mudflats
among mangroves at Sisal, of which the male was taken on August 7.
Although Paynter (1955a) indicated that this species probably breeds on
the peninsula, there are no definite breeding records. Our specimen had
only slightly enlarged testes, but its close association with a female
suggested that the pair may have been mated.

    Specimen (1): [Male], 40448, testis 7 × 3 mm., 189.4 gm., little
    fat (August 7), 5 mi. SW Sisal.

_Larus atricilla_ Linnaeus: Laughing Gull.--This species was seen
regularly along the coasts of the peninsula.

    Specimen (1): [Female], 40449, ovary 7 mm. (inactive), 253 gm.
    (August 7), 4-3/10 mi. W Sisal. Mallophaga: _Quadraceps_ sp.

_Sterna albifrons antillarum_ (Lesson): Least Tern.--A flock of about
20 individuals was seen on Isla Mujeres; two individuals were shot and
appear to be the first specimens from the island.

    Specimens (2): [Female], 40451, ovary slightly enlarged, 49.0 gm.
    (August 2); sex? 40450, 41.8 gm. (August 2), Isla Mujeres.

_Thalasseus sandvicensis_ (Latham): Cabot Tern.--Lone individuals were
seen several times flying along the coast southwest of Sisal.

    Specimen (1): [Male], 40452, 186 gm. (August 11), 13 km. WSW Sisal.
    Mallophaga: _Saemundssonia brevicernis_.

_Patagioenas flavirostris flavirostris_ (Wagler): Red-billed Pigeon.--This
species was seen at all stations except on the islands and in the arid
scrub at Sisal. It was especially abundant at Escárcega, Felipe
Carrillo Puerto, and Puerto Juarez. The male in breeding condition
suggests that the breeding season extends into the summer.

    Specimens (5): [Female], 40455, ovary inactive (July 13), [Female],
    40456, ovary inactive, (July 13), and [Male], 40457, testis 7 × 5
    mm. (July 15), 6-{7-1/2} km. W Escárcega; [Male], 40453, testis 15
    × 6 mm., 225.5 gm. (August 16), and [Female], 40454, ovary
    inactive, 228 gm. (August 16), 4 km. NNE Felipe Carrillo Puerto.
    Mallophaga: _Columbicola_ sp., July 15.

_Zenaida aurita yucatanensis_ Salvadori: Zenaida Dove.--This species
was common at Sisal.

    Specimens (3): [Female], 40459, imm., 136.5 gm., little fat (August
    11), 8 km. SW Sisal; [Female], 40399, 151.2 gm. (August 7), 1-1/2
    mi. S Sisal; [Female], 40400, 163.3 gm. (August 18), 2 km. WSW
    Sisal. Mallophaga: _Columbicola macrouras_, August 7.

_Zenaida asiatica_ Linnaeus: White-winged Dove.--Birds of this species
were ubiquitous in the scrub west of Sisal between 10 a.m. and 4 p.m.
but inconspicuous at other times. Apparently the birds were from nests,
roosts, and watering sites in the taller forest inland.

_Columbina passerina pallescens_ (Baird): Common Ground Dove.--This
species was common at almost all collecting localities, but was always
outnumbered by the Ruddy Ground Dove. The species was not seen in the
vicinity of Escárcega, probably because of the tall forest and lack of
clearings there.

    Specimens (5): [Male], 40461, testis 10 × 5 mm., 40.9 gm. (August
    10), 2 km. WSW Sisal; [Male], 40460, testis 6 × 3 mm. (August 9),
    and [Female], 40464, ova to 4 mm., 37 gm. (August 9), {3-1/2}-4 km.
    N San Miguel, Isla Cozumel; [Female], 40463, imm., molting, 35.5
    gm. (August 15), 4 km. NNE Felipe Carrillo Puerto.

_Columbina talpacoti rufipennis_ (Bonaparte): Ruddy Ground Dove.--This
dove was common at all localities visited. All specimens were in
breeding condition.

    Specimens (9): [Female], 40472, ova to 3 mm., 45.4 gm. (July 8),
    [Male], 40468, testis 10 × 5 mm., 50.0 gm (July 8), [Male], 40469,
    testis 10 × 5 mm., 65.5 gm. (July 8), [Female], 40470, ova to 3
    mm., 51.6 gm. (July 8) and [Male], 40471, testis 9 × 5 mm., 57.5
    gm. (July 8), all from the vicinity of Puerto Real Isla del Carmen;
    [Female], 40467, 57.7 gm., (July 10), 5 km. S Chapotón; [Male],
    40473, testis 8 × 5 mm., 53.0 gm. (July 17), 1 km. N, 13 km. W
    Escárcega; [Female], 40465, ova to 21 mm., 51.8 gm. (July 28);
    Pueblo Nuevo X-can; [Male], 40466, testis 8 × 4 mm., 46.6 gm.
    (August 16), 4 km. NNE Felipe Carrillo Puerto.

_Claravis pretiosa_ (Ferrari-Perez): Blue Ground Dove.--This species
was seen only at Pueblo Nuevo X-can where a breeding pair was taken on
July 29; this record extends the known breeding season by one month
(see Paynter, 1955b).

    Specimens (2): [Male], 40475, testis 10 × 5 mm., 65.0 gm. (July
    29), and [Female], 40474, ova to 9 mm., 68.3 gm. (July 29), Pueblo
    Nuevo X-can.

_Leptotila verreauxi fulviventris_ Lawrence: White-fronted Dove.--My
only records of this species are the two specimens listed below. Both
birds had slightly enlarged ovaries and the one from west of Escárcega
was molting. Paynter (1955a) recorded breeding from late January to
late April.

    Specimens (2): [Female], 40476, ova to 2 mm., molting--5th and 6th
    primaries ensheathed (July 14), 7-1/2 km. W Escárcega; [Female],
    40477, ovary 12 × 5 mm., 162 gm. (August 14), 4 km. NNE Felipe
    Carrillo Puerto.

_Leptotila jamaicencis gaumeri_ (Lawrence): Caribbean Dove.--Two were
collected on Isla Cozumel and the several white-fronted doves seen on
Isla Mujeres probably were of this species.

    Specimens (2): [Male], 40478, testis 9 × 5 mm., 175 gm.,
    molting--4th primaries ensheathed (August 9), and [Female], 40479,
    imm., 116.7 gm., molting--2nd primaries ensheathed (August 10),
    3-1/2 km. N San Miguel.

_Oreopeleia montana montana_ (Linnaeus): Ruddy Quail-dove.--My only
record is of a male, in full breeding condition, which extends the
known breeding period almost two months.

    Specimen (1): [Male], 40480, testis 19 × 8 mm., 144.7 gm. (July
    29), Pueblo Nuevo X-can.

_Artinga astec astec_ (Souancé): Aztec Parakeet.--This species was most
common in deciduous forest and scrub at Champotón, Pisté, Puerto
Juarez, and especially Felipe Carrillo Puerto. Parakeets were extremely
wary and only two were collected.

    Specimens (2): [Male], 40481, testis 3 × 2 mm., 75.0 gm.,
    molting--extensive body molt, 8th primaries ensheathed, middle pair
    of rectrices are new (August 16), and [Female], 40482, ovary
    inactive, 72.4 gm. (August 16), 4 km. NNE Felipe Carrillo Puerto.

_Amazona xantholora_ (Gray): Yellow-lored Parrot.--The species was
abundant in the vicinity of Champotón. Large flocks congregated near
camp; the birds began to assemble about an hour before dark. One was
shot from a flock that flew over our camp and another was taken at
night from its roost in a small tree about 10 feet above a trail. One
small flock of _Amazona_ was seen 4 km. NNE Felipe Carrillo Puerto. All
specimens were molting.

    Specimens (3): [Male], 40483, testis 5 × 2 mm., 229.1 gm.,
    molting--extensive body molt, 6th primaries ensheathed (July 9),
    and [Female], 40484, ovary 13 × 9 mm. (inactive), 209.0 gm.,
    molting--extensive body molt, wing molt complete (July 11), 5 km. S
    Champotón; [Male], 40485, testis 5 × 2 mm., 210.9 gm.,
    molting--extensive body molt, 7th primaries ensheathed (August 16),
    4 km. NNE Felipe Carrillo Puerto.

_Amazona albifrons nana_ Miller: White-fronted Parrot.--This species
was common west of Escárcega where large flocks were seen every
evening. A specimen of _A. albifrons_ was taken south of Champotón
where this species occurred in large flocks with _A. xantholora_. One
specimen was taken from a small flock near Chichén-Itzá.

    Specimens (5): [Male], 40487, testis 8 × 4 mm., 210.0 gm. (July
    10), 5 km. S. Champotón; [Female], 40488, ovary inactive, 205.5
    gm., molting (July 12), [Male], 40489, 232.5 gm., molting (July
    13), and [Female], 40490, ovary inactive, 206.1 gm. (July 14),
    7-1/2 km. W Escárcega; [Female], 40486, ovary inactive, 176.0 gm.
    (July 27), 2 km. E Chichén-Itzá.

_Coccyzus americanus americanus_ (Linnaeus): Yellow-billed Cuckoo.--A
female taken at Pisté substantiates Paynter's (1955a) suggestion that
the species breeds on the peninsula.

    Specimen (1): [Female], 40491, ovary 12 × 9 mm., 58.7 gm.,
    well-developed brood patch (July 22), Pisté.

_Coccyzus minor_ (Gmelin): Mangrove Cuckoo.--In view of the paucity of
recent records of this species from the mainland of the peninsula, it
is noteworthy that several individuals were seen flying to and from the
beach and mangroves late one evening about 4 km. W Sisal.

_Piaya cayana thermophila_ Sclater: Squirrel Cuckoo.--This species was
seen at our camps near Champotón, Pisté, Pueblo Nuevo X-can, and Puerto
Juarez. The slightly enlarged (probably regressing) testes of males
examined seem to be the only evidence of breeding activity in the
species on the peninsula.

    Specimens (3): [Male], 40493, testis 8 × 6 mm., 99.6 gm. (July 14),
    and [Female], 40494, 90.0 gm. (July 14), 7-1/2 km. W Escárcega;
    [Male], 40492, testis 5 × 2 mm., 97.5 gm., molting (August 14), 4
    km. NNE Felipe Carrillo Puerto.

_Crotophaga sulcirostris sulcirostris_ Swainson: Grove-billed
Ani.--Three half-grown juveniles were taken at Pisté and a pair in
breeding condition was taken at Pueblo Nuevo X-can. These seem to be
the first breeding records from the peninsula.

    Specimens (5): [Male], 40495, juv., 39.9 gm. (July 21), [Male],
    40496, juv., 39.5 gm. (July 21), and [Female], 40497, juv., 30.0
    gm. (July 21), Pisté; [Male], 40498, testis 11 × 4 mm., 72.2 gm.
    (July 28), and [Female], 40499, ova to 7 mm., 70.0 gm. (July 28),
    Pueblo Nuevo X-can.

_Crotophaga ani_ Linnaeus: Smooth-billed Ani.--The female taken on Isla
Cozumel had a slightly enlarged ovary and had been banded (USFWS band
no. 524-96303) on the island in 1961 as an adult.

    Specimen (1): [Female], 40500, ovary 11 × 7 mm., 86 gm., molting
    (August 4), 3-1/2 km. N San Miguel.

_Glaucidium brasilianum ridgwayi_ Sharpe: Streaked Pygmy Owl.--A female
(40501) was taken by a local boy at Pueblo Nuevo X-can on July 29
weighed 62 gm. and the ovary (7 × 3 mm.) was inactive.

_Ciccaba virgata centralis_ Griscom: Squamulated Owl.--Our only
specimen, a female (40502) weighing 288.7 gm. and having an inactive
ovary (13 × 4 mm.), was taken at night on July 16 from a mist net
stretched across a small trail 1 km. N, 13 km. W Escárcega.

_Nyctibius griseus mexicanus_ Nelson: Mexican Potoo.--One specimen was
taken at night 7-1/2 km. W Escárcega where it was found sitting on the
limb of a large dead tree. A light but steady rain was falling at the
time. On the night of August 16 along a stretch of newly-constructed
road 4-16 km. NNE Felipe Carrillo Puerto, 27 potoos were seen, their
large and brilliant, amber-colored eyes first appearing in the
headlights several hundred yards ahead of our vehicle. All of the birds
were perched between 30 and 60 feet above the ground on dead limbs of
large trees, and all were perched on the same side of the road facing
the light of a full moon. None was less than 200 meters from the next;
few flew at the approach of our vehicle. In addition to one specimen
taken along the road, another was taken from a fence post in a _milpa_
on the same night. It was approached close enough to be shot with a 22
caliber pistol loaded with dust-shot. All specimens had thick layers of
subcutaneous and visceral fat and their gonads were small and seemingly
inactive.

    Specimens (3): sex? 40505 (July 13) 7-1/2 km. W Escárcega;
    [Female], 40504, ovary 13 × 4 mm. (inactive), 265 gm. (August 16),
    and [Male], 40503, testis 5 × 3 mm., 320.5 gm. (August 16) 4 km.
    NNE Felipe Carrillo Puerto.

_Chordeiles acutipennis micromeris_ Oberholser: Trilling Nighthawk.--This
species was common in the arid coastal scrub west of Sisal, where
hundreds could be seen flying every evening. They were common also at
Puerto Juarez, but uncommon at Felipe Carrillo Puerto.

    Specimens (2): [Male], 40506, testis 5 × 3 mm., 57.3 gm. (August
    1), 5 km. WSW Puerto Juarez; [Female], 40507, ovary 4 × 3 mm.
    (inactive), 37.0 gm. (August 16), km. NNE Felipe Carrillo Puerto.

_Nyctidromus albicollis yucatanensis_ Nelson: Parauque.--This species
was especially common in the vicinity of Felipe Carrillo Puerto and on
Isla Cozumel, and was seen at every collecting locality. A flightless,
juvenal female was obtained by local boys at Pisté on July 21.
Therefore the reproduction period seems to be longer than Paynter's
(1955a:141) data suggested.

    Specimens (5): [Male], 40512, testis 7 × 3 mm., 75 gm. (July 10), 5
    km. S Champotón; [Female], 40508, juv. (remiges and rectrices
    ensheathed basally), 44.2 gm. (July 21), Pisté; sex? 40510, 55.5
    gm. (August 8), and [Male], 40509, testis 3 × 1 mm., 73.5 gm.,
    molting--outermost two pairs of primaries ensheathed (August 10);
    3-1/2 km. N San Miguel, Isla Cozumel; [Male], 40511, 72.9 gm.
    (August 15), 4 km. NNE Felipe Carrillo Puerto.

_Caprimulgus salvini badius_ (Bangs and Peck): Salvin's Whip-poor-will.--My
only record of this species is provided by a female (40513) taken 3-1/2
km. N San Miguel, Isla Cozumel, on August 8. The specimen weighed 58
grams, had an inactive ovary (6 × 4 mm.), and was molting (8th and 9th
primaries ensheathed).

_Chateura vauxi gaumeri_ Lawrence: Vaux Swift.--This species was seen
at almost every locality visited. The only specimens obtained were
brought in by a boy at Pueblo Nuevo X-can on July 30; he said he
captured them in his house. Two of them were adults and four were
fully-feathered young-of-the-year.

    Specimens (6): [Male], 40516, testis 4 × 2 mm., [Female], 40519,
    ovary inactive, [Male], 40514, juv., 12.6 gm., [Male], 40515, juv.,
    [Female], 40517, juv., and [Female], 40518, juv. (July 30) Pueblo
    Nuevo X-can.

_Campylopterus curvipennis pampa_ (Lesson): Saber-wing.--A female
(40522), shot 7-1/2, km. W Escárcega on July 16, seems to provide the
first record of breeding (ovum 6 mm. in oviduct) by this species on the
peninsula. A non-breeding female (40521) that weighed 5.0 gms. was
taken 4 km. NNE Felipe Carrillo Puerto on August 14.

_Chlorostilbon canivetii canivetii_ (Lesson): Canivet Emerald.--This
bird was seen at all localities at which we collected on the mainland.

    Specimens (4): [Female], 40530, ovary moderately active, 3.0 gm.
    (July 22), [Male], 40525, 2.1 gm. (July 23), and sex? 40526, 2.9
    gm. (July 25), Pisté; [Female], 40529, ovary inactive, 2.4 gm.
    (July 26), 3-1/2 km. N Pisté.

_Chlorostilbon canivetii forificatus_ Ridgway: Canivet Emerald.--The
specimen is slightly larger than those taken on the mainland and is
clearly referable to _C. c. forificatus_, a subspecies endemic to Isla
Cozumel.

    Specimen (1): [Female], 40534, ovary inactive, 2.8 gm. (August 8),
    3-1/2 km. N San Miguel, Isla Cozumel.

_Amazilia candida candida_ (Bourcier and Mulsant): White-bellied
Emerald.--This species seemed to be the commonest hummingbird at most
localities on the mainland. However, it was not seen along the coasts.

    Specimens (5): [Male], 40535, testis 3 mm., 2.9 gm. (July 12), and
    [Male], 40536, testis 2 mm., 3.6 gm. (July 14), 7-1/2 km. W
    Escárcega; [Male], 40531, testis 2 mm., 4.3 gm. (July 28), [Male],
    40532, 3.8 gm. (July 28), and [Female], 40533, ovary inactive, 3.9
    gm. (July 29), Pueblo Nuevo X-can.

_Amazilia rutila_ (DeLattre): Cinnamomeous Hummingbird.--In addition to
the two localities from which specimens were taken, several individuals
were seen near the airstrip at Puerto Juarez.

    Specimens (2): [Female], 40538, ovary inactive, 4.1 gm. (July 30),
    1-1/2 km. S, 1 km. E Pueblo Nuevo X-can; [Male], 40539, testis 2
    mm. (August 14), 4 km. NNE Felipe Carrillo Puerto.

_Amazilia yucatanensis_ (Cabot): Yucatán Hummingbird.--Many of these
hummingbirds were seen among the coco palms on Isla del Carmen. A
female taken on August 14 with a moderately enlarged ovary may indicate
that the breeding season extends well into the summer.

    Specimens (4): [Male], 40540, testis 2 mm., 4.7 gm. (July 7),
    [Female], 40541, ovary inactive, 3.0 gm. (July 8), and [Male],
    40543, 3.0 gm. (July 8); 1 km. SW Puerto Real, Isla del Carmen;
    [Female], 40542, ovary 6 × 2 mm. (ova to 1 mm.), 2.9 gm. (August
    14), 4 km. NNE Felipe Carrillo Puerto.

_Trogon citreolus melanocephala_ Gould: Citreoline Trogon.--This
species was heard or seen at all localities where deciduous forest was
present.

    Specimens (7): [Female], 40557, ovary 14 × 8 mm. (ova to 2 mm.),
    brood patch, 72.5 gm. (July 16), and [Male], 40558, 66.5 gm. (July
    16), 7-1/2 km. W Escárcega; [Male], 40553, 74.0 gm. (August 1),
    [Female], 40552, 74 gm. (August 1), [Female], 40554, ova to 3 mm.
    (August 2), and [Male], 40555, 76.2 gm. (August 2), 4 km. WSW
    Puerto Juarez; [Female], 40556, 76.4 gm. (August 15), 4 km. NNE
    Felipe Carrillo Puerto.

_Chloroceryle americana septentrionalis_ (Sharpe): Green Kingfisher.--My
only specimen is a male (40559) shot near a large aguada at Rancho San
Miguel, 4 km. NNE Felipe Carrillo Puerto on August 16. The specimen
weighed 40.5 gm.

_Ceryle torquata_ (Linnaeus): Ringed Kingfisher.--Paynter (1955a:154)
noted that this "species has not been recorded from Yucatán but it is
undoubtedly present, at least in the sheltered lagoon behind the
barrier bar." A single individual was seen in one of these lagoons on
August 9 and 10.

_Eumomota superciliosa superciliosa_ (Sandbach): Turquoise-browed
Motmot.--On July 9 this species was nesting in a large "colony" 5 km. S
Champotón, Campéche, in a large abandoned gravel pit having vertical
banks about 10 feet high. The pit was an irregular semicircle with an
approximate radius of 100 yards and was bordered by a road on one side
and elsewhere by low scrub vegetation. The pit was one of several found
in the area and formerly was used as a source of limestone gravel used
in constructing the road between Champotón and Escárcega. The exposed
limestone substratum was overlaid with chalky soil six to eight feet
deep.

Motmots were nesting in burrows dug in the layer of surface soil. A
total of 101 burrows seemed to be in use or to have been used in 1962.
Nine appeared to be unused and 24 burrows evidently were abandoned
before they were finished. The depths of 12 burrows selected at random
were 34, 32, 37, 25, 28, 44, 36, 36, 24, 37, 22, and 43 inches, and
averaged 33.4 inches. In cross-section the burrows varied from round
(three inches in diameter) to oval (three inches high and four inches
wide). The inner ends of the burrows were enlarged with a depression in
the floor, where the eggs were laid.

The long axes of most burrows were straight and perpendicular to the
face of the bank in which they were dug; two burrows nevertheless were
curved laterally, and one was U-shaped, having two entrances that
opened about 12 inches apart.

Eggs and nestlings were found lying on the bare soil at the inner ends
of the burrows; no nesting material was found.

The contents of 10 burrows that were excavated are summarized in Table
1. Three nests contained no eggs or young. One of these was freshly
dug. The other two empty burrows apparently had been recently occupied
by nestlings and contained the foul smelling remains of fecal material,
hundreds of beetle wings, and other undigestible parts of insects. The
manure was teeming with large fly larvae.

  TABLE 1. Contents of 10 burrows of Turquoise-browed Motmots.

  Burrow     Fresh    Eggs     Nestlings    Post-fledgling
   1           *
   2                   4
   3                             3
   4                             4
   5                   1         3
   6                             4
   7                             1
   8                   x
   9                                            *
  10                                            *

  * Nothing.
  x Broken egg shells.

Three burrows contained nestlings; one had four young with pin
feathers, one a chick fully feathered, and one three newly hatched
young and one egg.

In burrow 2, three eggs had advanced embryos and one was infertile; in
burrow 3, the eggs had small embryos; and in burrow 4, the eggs
appeared fresh. Burrows 3 and 4 were occupied by adult birds that did
not flush during the excavation of their burrows. They were easily
caught by hand and later prepared as specimens. One was a male and the
other a female; each had a brood patch.

Possibly females of this species raise more than one brood in a single
nesting season, but I have no direct evidence of this. Such an
hypothesis is suggested by the different stages of nestings found in
the burrows. Moreover, there were more than twice as many burrows as
motmots in the area. The largest number of individuals counted at any
time near the colony was 20 adults (about an hour after sunrise).
Assuming that all of these birds had mates, the maximum number of
adults present could have numbered about 40.

There is another bit of evidence for double broods. Because of fouling
of the burrow that accompanies the raising of a brood of young, it
seems improbable that a burrow would be used immediately for a second
nesting attempt. Consequently digging a second burrow would be
necessary, if a second brood is raised.

Most of my observations are in keeping with Skutch's detailed report
(1947) of the species in Central America. According to him, eggs are
laid in April and May in Honduras and Guatamala, although he did not
state that breeding does not occur in other months. The observations in
Campeche in early July suggest that breeding can occur over an extended
period; Paynter (1955a:158) found the species to be in various stages
of reproductive activity in April on the peninsula.

Skutch suggested that the motmots he observed in Central America were
solitary nesters, and nest in "groups" only where suitable nesting
sites are scarce. In Campeche, many suitable, seemingly identical, but
unused, nesting sites were available within a few hundred yards of the
site of the actual nesting "colony." Moreover, most of the burrows were
only a few feet apart and no agonistic behavior was witnessed. It seems
that this motmot is characterized by colonial nesting habits in
Campeche, even where abundant sites for individual nesting efforts are
available.

The species was abundant around the _cenotes_ at Chichén-Itzá; adults
with enlarged gonads and brood patches and juveniles were taken at
Pisté as late as July 21.

    Specimens (19): [Male], 40565, brood patch, 59.4 gm. (July 9),
    [Male], 40564, testis 8 × 4 mm., brood patch, 68.0 gm. (July 9),
    [Male], 40566, 74 gm. (July 9), [Female], 40567, juv. (July 9),
    [Male], 40568, testis 5 × 3 mm., 68.3 gm. (July 10), [Male], 40578,
    59.5 gm. (July 11), and [Female], 40577, ova to 2 mm., brood patch,
    65.2 gm. (July 11), all from 5 km. S Champotón; [Male], 40560, 43.6
    gm. (July 20), [Female], 40562, brood patch, 55 gm. (July 21), sex?
    40561, 64 gm. (July 21), and [Female], 40563, juv. (July 22),
    Pisté. Eight nestlings (40569-76) that were taken from burrows at 5
    km. S Champotón on July 11 had the following weights: 42.4 gm.,
    39.7 gm., 38.5 gm., 12.2 gm., 40.0 gm., 30.7 gm., 26.8 gm., 19.0
    gm. Mallophaga: _Philopterus_ sp., July 9.

_Momotus momota lessonii_ Lesson: Blue-crowned Motmot.--For convenience,
the specimens from 5 km. S Champotón are assigned to _M. m. lessonii_
on the basis of measurements (wing 139 mm., tail 240 mm., culmen [from
feathers] 41.0 mm.) taken on one specimen (40579), which are within the
limits of the subspecies as described by Ridgway (1914). Two other
specimens from that locality were prepared as skeletons and their
weights are essentially the same as those Paynter (1955a) recorded for
_M. m. lessonii_. According to Paynter, there is a southward clinal
increase in size in this species between the smaller _M. m. exiguus_ in
the northern part of the peninsula and _M. m. lessonii_ in the extreme
southern part. A more extensive series of specimens from the vicinity
of Champotón probably would reveal a population intermediate in size
between the typical representatives of the two races.

    Specimens (3): [Female], 40579, 105 gm. (July 10), [Female], 40581,
    98.9 gm. (July 11), [Male], 40580, 102.5 gm. (July 11), 5 km. S
    Champotón.

_Pteroglossus torquatus erythrozonus_ Ridgway: Collared Aracari.--A
male taken at Pueblo Nuevo X-can on July 27 and a female from 4 km. NNE
Felipe Carrillo Puerto on August 15 had slightly enlarged gonads, which
probably were regressing. Apparently these are the first indications of
breeding activity for this species on the peninsula.

    Specimens (5): [Male], 40586, testis 4 × 2 mm., 155 gm. (July 16),
    7-1/2 km. W Escárcega; [Male], 40582, testis 10 × 5 mm., 169.1 gm.
    (July 27), and [Female], 40583, ovary inactive, 137.3 gm. (July
    29), Pueblo Nuevo X-can; [Female], 40584, ovary 10 × 6 mm., 169.5
    gm. (August 15), and sex? 40585, 148.9 gm. (August 16), 4 km. NNE
    Felipe Carrillo Puerto.

_Rhamphastos sulfuratus sulfuratus_ Lesson: Keel-billed Toucan.--This
species was especially common west of Escárcega, where it was most
often seen in small flocks of less than 10 birds. Presumably breeding
had already occurred; four specimens had inactive gonads.

    Specimens (7): [Female], 40589, 367.3 gm. (July 12), [Male], 40588,
    testis 8 × 3 mm., 414.5 gm. (July 14), [Female], 40590, ovary 11
    mm., 347.4 gm. (July 15), [Male], 40591, testis 5 × 3 mm., 371 gm.
    (July 15), [Male], 40593, testis 6 × 3 mm., 422.2 gm. (July 16) and
    [Male], 40592, 401.5 gm. (July 16), 6-7-1/2 km. W Escárcega;
    [Female], 40587, 395.5 gm. (July 28), Pueblo Nuevo X-can.

_Piculus rubiginosus yucatanensis_ (Cabot): Red-capped Green
Woodpecker.--Specimen (1): [Female], 40594, ovary inactive (7 × 4 mm.),
extensive body molt, 67.7 gm. (August 17), 4 km. NNE Felipe Carrillo
Puerto. Mallophaga: _Penerirmus_ sp.

_Drycopus lineatus similis_ (Lesson): Lineated Woodpecker.--Specimen
(1): [Male], 40595, molting, 141.2 gm. (July 15), 7-1/2 km. W
Escárcega.

_Centurus aurifrons dubius_ (Cabot): Golden-fronted Woodpecker.--The
gonads were moderately enlarged in several of the specimens taken in
the first half of July. The plumage was much worn in all specimens and
some were in early stages of molt. Apparently the breeding season on
the peninsula extends to at least mid-July. The specimen from Isla
Cozumel is assigned to _C. a. dubius_, following the systematic
treatment by Selander and Giller (1963).

    Specimens (10): sex? 40602, 75.0 gm. (July 8), and [Female], 40601,
    ovary 6 × 3 mm. (enlarged oviduct), 76.4 gm. (July 10), 1 km. S
    Puerto Real, Isla del Carmen; [Male], 40599, testis 6 × 8 mm.,
    101.3 gm. (July 10), and [Male], 40600, 86.0 gm. (July 11), 5 km. S
    Champotón; [Male], 40603, testis 5 × 3 mm. (July 14), and [Female],
    40604, ovary 6 × 4 mm. (ova to 1 mm.), brood patch (July 16), 7-1/2
    km. W Escárcega; sex? 40596, molting, much visceral fat, 79.0 gm.
    (July 22), Pisté; [Female], 40597, 73.7 gm. (July 28), Pueblo Nuevo
    X-can; [Female], 40598, 79.6 gm. (August 15), 4 km. NNE Felipe
    Carrillo Puerto; [Male], 40605, testis inactive, molting, much
    visceral fat (August 8), 3.5 km. N San Miguel, Isla Cozumel.

_Centurus pygmaeus_ (Peters): Yucatán Woodpecker.--Paynter (1955a:166)
reported evidence of breeding in this species on April 3 and May 23; a
male having enlarged testes was taken on July 10.

    Specimens (5): [Male], 40608, testis 6 × 4 mm. (July 10); [Female],
    40607, 39.5 gm. (July 10), 5 km. S Champotón; [Male], 40609, testis
    inactive, 35.8 gm., moderate visceral fat (July 17), 1 km. N, 13
    km. W Escárcega; [Female], 40606, ovary 6 × 4 mm. (inactive), 37.0
    gm. (August 14), 4 km. NNE Felipe Carrillo Puerto; [Male], 40610,
    testis inactive, heavy visceral and subcutaneous fat, 41.6 gm.,
    (August 10), 3-1/2 km. N San Miguel, Isla Cozumel.

_Phloeoceastes guatemalensis guatemalensis_ (Hartlaub): Guatemalan
Ivory-billed Woodpecker.--Specimens (4): [Male], 40611, right testis 2
mm., left testis vestigial, 203.7 gm. (July 23), Pisté; 40612, sex? 212
gm., (July 28), and [Female], 40613, 218.1 gm. (July 30), Pueblo Nuevo
X-can; [Female], 40614, 189.2 gm. (August 15), 4 km. NNE Felipe
Carrillo Puerto.

_Dendrocincla anabatina_ (Sclater): Tawny-winged Woodhewer.--Specimen
(1): [Male], 40615, testis 2 × 1 mm., 35.7 gm., molting--5th primaries
and middle pair of rectrices ensheathed (July 17), 1 km. N, 13 km. W
Escárcega.

_Dendrocincla homochroa homochroa_ (Sclater): Ruddy Woodhewer.--May 20
seems to be the only previous date of record for breeding in this
species (Paynter, 1955a:171); our specimen extends the known season
nearly three months.

    Specimen (1): [Female], 40616, ovary 13 × 6 mm. (ova to 2 mm.),
    brood patch, 35.1 gm. (August 16), 4 km. NNE Felipe Carrillo
    Puerto.

_Sittasomus griseicapillus_ (Vieillot): Olivaceous Woodcreeper.--
Specimens (2): [Male], 40617, juv., 11.2 gm. (July 26), Pisté;
[Female], 40618, ovary inactive, 10.5 gm. (August 15), 4 km. NNE Felipe
Carrillo Puerto.

_Xiphorhynchus flavigaster_ (Swainson): Ivory-billed Woodcreeper.--
According to Paynter (1955a:173), indications of breeding have been
observed in specimens of this species taken between March 27 and June
5. A male taken on August 15 had moderately enlarged (probably
regressing) testes and was well into the molt.

    Specimen (1): [Male], 40619, testis 5 × 3 mm., 51.5 gm.,
    molting--5th primaries and middle pair of rectrices ensheathed
    (August 15), 4 km. NNE Felipe Carrillo Puerto.

_Lepidocolaptes souleyetii_ (Des Murs): Streak-headed Woodhewer.--This
appears to be the second specimen recorded from the peninsula (see
Traylor, 1941).

    Specimen (1): [Male], 40621, testis 3 × 1 mm., 26.6 gm., molting--6th
    primaries ensheathed, middle pair of rectrices are new (July 17), 1
    km. N, 13 km. W Escárcega.

_Synallaxis erythrothorax_ Sclater: Rufous-breasted Spinetail.--Specimen
(1): [Male], 40622, imm. skull, 16.1 gm. (August 16), 4 km. NNE Felipe
Carrillo Puerto.

_Thamnophilus doliatus_ (Linnaeus): Barred Antshrike.--Specimen (1):
[Female], 40623, ovary 8 × 5 mm. (inactive), 26 gm. (August 14), 4 km.
NNE Felipe Carrillo Puerto.

_Formicarius analis_ (d'Orbigny and Lafresnaye): Black-chinned
Antthrush.--Specimen (1): [Male], 40624, 56.0 gm. (July 29), Pueblo
Nuevo X-can.

_Pachyramphus major itzensis_ Nelson: Mexican Becard.--Previous records
of breeding in this species are provided by a female obtained on July
12 (Paynter, 1955a:182) and a male taken on June 9 (Paynter, 1955b).

    Specimen (1): [Male], 40625, testis 9 × 5 mm., 22.1 gm. (July 21),
    Pisté.

_Platypsaris aglaiae_ (Lafresnaye): Rose-throated Becard.--All
specimens have extensively worn plumage.

    Specimens (3): [Male], 40628, 33.5 gm. (July 10), 5 km. S
    Champotón; [Female], 40626, ovary 6 × 3 mm., brood patch, 34.0 gm.
    (July 20), [Female], 40627, ovary inactive, 33.9 gm. (July 26);
    3-1/2 km. N and 6-1/2 km. W Pisté.

_Tityra semifasciata personata_ Jardine and Selby: Masked Tityra.--
Previously, breeding information for this species has been available
only for March (Paynter, 1955a:184). Adults were observed feeding young
fledglings 7-1/2 km. W Escárcega on July 15, and a juvenile was taken.
Gonads of males were in full breeding condition.

    Specimens (5): [Male], 40630, testis 13 × 6 mm., 81.3 gm. (July
    14), sex? 40631, juv., 55.5 gm. (July 15), [Male], 40632, testis 9
    × 5 mm., 73 gm., molting--1st and 2nd primaries ensheathed (July
    15), and [Female], 40633, 84.7 gm. (July 16), 7-1/2 km. W
    Escárcega; [Female], 40629, ova to 1 mm., 80.0 gm. (July 23),
    Pisté.

_Erator inquisitor fraserii_ (Kaup): Black-capped Tityra.--Breeding has
been recorded by Paynter (1955a:185) on April 26. A moderately enlarged
testis (probably regressing) was noted in the specimen from Pisté, on
July 21.

    Specimens (2): [Female], 40635, 51.8 gm. (July 15), 7-1/2 km. W
    Escárcega; [Male], 40634, testis 6 mm., 51 gm., molting--6th
    primaries ensheathed (July 21), Pisté.

_Pipra mentalis mentalis_ Sclater: Red-capped Manakin.--The specimens
here reported seem to be the first from the peninsula in which
reproductive activity has been recorded.

    Specimens (2): [Male], 40637, testis 5 × 3 mm., 14.0 gm. (July 29),
    Pueblo Nuevo X-can; [Male], 40636, testis 5 × 2 mm., 14.6 gm.
    (August 3), 4 km. WSW Puerto Juarez.

_Pyrocephalus rubinus_ (Boddaert): Vermillion Flycatcher.--This species
was seen only in the arid scrub 2-13 km. WSW of Sisal. Breeding
seemingly had ended by early August, as evidenced by four adults that
showed no gonadal activity and were in advanced stages of molt.

    Specimens (5): [Female], 40638, juv., 12.1 gm. (August 7), 1-1/2
    mi. S Sisal; [Female], 40640, ovary inactive, 14.1 gm.,
    molting--6th primaries ensheathed (August 10), [Female], 40641,
    ovary inactive, 13.9 gm., molting--7th primaries ensheathed (August
    10), and [Male], 40642, testis 2 mm., 14.6 gm., molting--5th
    primaries ensheathed (August 10), 13 km. WSW Sisal; [Female],
    40639, testis 1 mm., 14.0 gm., molting--7th primaries ensheathed
    (August 18), 2 km. SW Sisal.

_Tyrannus melancholicus chloronotus_ Berlepsch: Tropical Kingbird.--Most
specimens were molting. A male and two females from Pisté taken on July
21 and a female from Pueblo Nuevo X-can (July 29) had slightly enlarged
(probably regressing) gonads. Three immatures were collected and adults
were seen feeding young fledglings at Pisté. There seems to be no other
breeding records from the peninsula.

    Specimens (10): [Female], 40650, 42 gm., (July 10), 5 km. S
    Champotón; [Female], 40752, ovary inactive, 43.4 gm., molting--4th
    primaries ensheathed (July 14), and [Male], 40651, imm., 42.5 gm.
    (July 15), 6-7-1/2/# km. W Escárcega; [Female], 40645, ovary
    slightly enlarged (8 × 3 mm.), 47.5 gm. (July 21), [Female], 40643,
    ova to 1 mm., 39.3 gm. (July 21), [Male], 40644, testis 10 × 7 mm.,
    43.1 gm., starting to molt--1st primaries ensheathed (July 21), and
    [Female], 40646, imm., (July 26), Pisté; [Female], 40648, ova to 1
    mm., 37.4 gm. (July 29), Pueblo Nuevo X-can; [Male], 40647, imm.,
    38.4 gm. (August 14), and [Female], 40649, 44.4 gm., molting--only
    outer 3 pairs of rectrices present and are ensheathed basally, 6th
    and 7th primaries ensheathed (August 15), 4 km. NNE Felipe Carrillo
    Puerto.

_Myiodynastes luteiventris luteiventris_ Sclater: Sulfur-bellied
Flycatcher.--The latest breeding record given by Paynter (1955a:191) is
for the last week in June. A male taken on July 31 had enlarged testes.
None of the following specimens was in the process of molt.

    Specimens (4): [Female], 40655, 44.5 gm. (July 10), 5 km. S
    Champotón; [Female], 40656, ovary slightly enlarged (8 × 4 mm.),
    47.0 gm. (July 15), 7-1/2 km. W Escárcega; [Female], 40654, testis
    10 × 4 mm., 39 gm. (July 31), Pueblo Nuevo X-can.

_Megarhynchus pitangua mexicanus_ (Lafresnaye): Boat-billed Flycatcher.--I
know of no previous breeding record for this species on the peninsula. The
female obtained on July 25 was observed feeding young.

    Specimens (2): [Female], 40658, 57.6 gm. (July 11), 5 km. S
    Champotón; [Female], 40657, ovary 10 × 5 mm., 59.8 gm. (July 25),
    Cenote Seco, 2 km. E Chichén-Itzá.

_Myiozetetes similis texensis_ (Giraud): Vermilion-crowned Flycatcher.
--Paynter (1955a:192) reported this species breeding in mid-May. A male
taken on July 17 west of Escárcega had enlarged (probably regressing)
testes and indicates breeding later than May.

    Specimens (3): [Male], 40660, testis 6 × 3 mm., 32.0 gm. (July 17),
    and sex? 40661, 33.8 gm., molting--5th primaries ensheathed (July
    17), 1 km. N, 13 km. W Escárcega; [Male], 40659, imm., testis 2 × 1
    mm., 27.6 gm. (July 29), Pueblo Nuevo X-can.

_Pitangus sulphuratus guatimalensis_ (Lafresnaye): Great Kiskadee.--
Apparently our specimens, which were in the late stages of breeding,
are the first evidence of reproduction for the species on the
peninsula.

    Specimens (4): [Female], 40663, ova to 1 mm., 50.7 gm. (July 9),
    and [Male], 40664, right testis 12 mm., 65.0 gm., body feathers in
    early stages of molt (July 9), 5 km. S Champotón; [Male], 40665,
    testis 5 mm., 61.9 gm., molting--middle pair of rectrices are new,
    6th primaries ensheathed (July 15), 7-1/2 km. W Escárcega; sex?
    40662, 59.5 gm. (August 14), 4 km. NNE Felipe Carrillo Puerto.
    Mallophaga: _Philopterus_ sp.

_Myiarchus tyrannulus cooperi_ Baird: Wied Flycatcher.--This species
was especially common among the coco palms on Isla del Carmen and Isla
Cozumel.

    Specimens (5): [Male], 40667, 36.7 gm. (July 8), [Male], 40668,
    36.6 gm. (July 8), sex? 40669, 39.4 gm. (July 8), and [Female],
    40670, 37.3 gm. (July 8), all from 1 km. SW Puerto Real, Isla del
    Carmen; [Female], 40666, ovary inactive, 34.9 gm. (August 10), 3
    km. N San Miguel, Isla Cozumel.

_Myiarchus tuberculifer platyrhynchus_ Ridgway: Olivaceous Flycatcher.
--Breeding specimens of this species have been known previously from
April and May (Paynter, 1955a:196); records listed beyond extend the
season nearly three months.

    Specimens (7): [Female], 40673, ova to 5 mm. (July 10), and
    [Female], 40674, ovary 7 × 3 mm. (ova to 1 mm.) (July 11), 5 km. SW
    Champotón; [Female], 40745, ovary inactive, 17.5 gm., starting to
    molt--1st, 2nd, and 3rd primaries ensheathed (July 16), 7-1/2 km. W
    Escárcega; [Female], 40671, imm., 16.1 gm. (July 20) Cenote Seco, 2
    km. E Chichén-Itzá; [Male], 40746, 18.2 gm. (July 22), Pisté;
    [Female], 40672, ovary inactive, 17.7 gm., molting--5th and 6th
    primaries and 1st secondaries ensheathed (August 15), 4 km. NNE
    Felipe Carrillo Puerto; [Male], 40675, left testis 13 mm., right
    testis 10 mm., 17.5 gm. (August 8), 3-1/2 km. N San Miguel, Isla
    Cozumel.

_Contopus cinereus_ (Spix): Tropical Pewee.--The regressing gonads of
the male taken on July 21 in an early stage of molt suggests breeding
on the peninsula.

    Specimens (2): [Male], 40676 testis 6 × 3 mm., 11.5 gm., starting
    to molt--1st and 2nd primaries ensheathed (July 21), 6-1/2 km. W
    Pisté; [Male], 40677, testis 1 mm., 12.6 mm., molting--4th, 5th,
    and 6th primaries and 2nd secondaries ensheathed (August 14), 4 km.
    NNE Felipe Carrillo Puerto.

_Tolmomyias sulphurescens_ (Spix): Sulphury Flat-Billed Flycatcher.--
Paynter (1955a:201) presented breeding records for this species from
mid-April to late June. My specimens seem to indicate that breeding
extends at least into July.

    Specimens (6): [Female], 40683, juv., 14.0 gm. (July 21), [Male],
    40684, juv. (remiges and rectrices ensheathed basally), 14.0 gm.
    (July 21), and [Male], 40682, testis 8 × 4 mm., 13.7 gm. (July 26),
    Pisté and 3-1/2 km. N Pisté; [Male], 40685, testis 7 × 4 mm., 15.3
    gm., molting--1st and 2nd primaries ensheathed (July 28), and
    [Female], 40686, ovary inactive (July 28), Pueblo Nuevo X-can;
    [Male], 40687, imm., 16.0 gm. (August 15), 4 km. NNE Felipe
    Carrillo Puerto. Mallophaga: _Philopterus_ sp. July 28; _Myrsidea_
    sp. July 28.

_Myiopagis veridicata_ (Vieillot): Yellow-crowned Elaenia.--The only
previous breeding record is of a male that was taken on April 29. My
only specimen has nearly fully enlarged testes.

    Specimen (1): [Male], 40688, testis 7 × 4 mm., 13.1 gm. (July 17),
    1 km. N, 13 km. W Escárcega.

_Progne subis subis_ (Linnaeus): Purple Martin.--A large migrant flock
of several thousand individuals of this species was present for several
days in August at Rancho San Miguel.

    Specimens (3): [Female], 40723, ovary inactive, 48.6 gm. (August
    14), [Female], 40724, 51.8 gm. (August 17), and [Female], 40725,
    imm. skull, 52.1 gm. (August 17), 4 km. NNE Felipe Carrillo Puerto.

_Petrochelidon fulva citata_ Van Tyne: Cave Swallow.--Throughout our
stay at Pisté, large numbers of Cave Swallows were seen flying in and
out of the small opening of a well-like _cenote_ in the center of the
village. Specimens were easily collected in a mist net placed across
the opening. No young Cave Swallows were taken and gonads of adults
were in various stages of reproductive activity. A few individuals
taken were beginning to molt. Probably the swallows were nesting in the
_cenote_ although the nests were inaccessible to view. Previous
breeding records are for April (Paynter, 1955a:209).

    Twenty-two specimens were collected, of which the following were
    taken at Pisté, July 21-25: [Male], 40693, testis 6 × 3 mm., 18.4
    gm.; [Male], 40696, 16.4 gm.; [Female], 40697, 18.2 gm.; [Male],
    40695, 15.0 gm.; [Female], 40690, ovary inactive, 18.4 gm.,
    molting--2nd primaries ensheathed; [Male], 40692, testis 5 × 3 mm.,
    17.9 gm.; [Female], 40698, 18.3 gm.; [Female], 40702, ovary 7 × 3
    mm., 18.9 gm.; [Female], 40703, ovary 6 × 3 mm., 17.5 gm.; [Male],
    40713, testis 3 mm., 18.4 gm.; [Female], 40704, 16.5 gm.; [Male],
    40705, 20.3 gm.; [Male], 40699, testis 2 mm., 18.6 gm.,
    molting--2nd primaries ensheathed; [Female], 40700, ovary 5 × 3
    mm., 18.5 gm., molting--1st primaries ensheathed; [Female], 40701,
    ovary 5 × 3 mm., 16.5 gm., molting--1st primaries ensheathed;
    [Male], 40707, testis 7 × 5 mm., 19.9; [Male], 40708, testis 4 × 3
    mm., 18.4 gm.; [Female], 40709, ovary 4 × 3 mm., 18.0 gm.; sex?
    40711, 18.3 gm., molting--1st and 2nd primaries ensheathed.

    Additional specimens are: [Female], 40718, 16.5 gm., molting--3rd
    primaries ensheathed (August 16), and [Female], 40719, 18.5 gm.,
    molting 1st primaries ensheathed (August 16), 4 km. NNE Felipe
    Carrillo Puerto; [Male], 40689, testis 1 mm., 16.2 gm.,
    molting--2nd primaries ensheathed (August 10), 13 km. WSW Sisal.
    Mallophaga: _Philopterus excisus_, July 21; _Myrsidea_ sp. July 21
    and 25.

_Stelgidopteryx ruficollis_ Audubon: Rough-winged Swallow.--Previous
records indicate that three subspecies of this species occur on the
Yucatán Peninsula (Paynter, 1955a:209). One of these, _S. r. ridgwayi_,
is resident. _S. r. serripennis_, representing the breeding population
occurring from British Columbia and New Hampshire over much of the
United States to central California, central Texas, and the Gulf
states, has been taken on the peninsula in winter. Paynter referred two
specimens taken in late September and three January-taken specimens to
_S. r. stuarti_, the highland race that breeds from the mountains of
southern Veracruz to Guatamala.

Allan R. Phillips had identified two immature individuals (40694 and
40712) from Pisté as _S. r. stuarti_; one specimen from Puerto Juarez
also is an immature and is nearly identical to those from Pisté. Two
adults from Pisté (40691 and 40710) are noticeably darker dorsally than
the immatures but are molting extensively and their identification to
subspecies is equivocal. Two other adults (40706 and 40715) were
prepared as skeletons.

Although mid-July seems early for _S. r. stuarti_ to be present on the
peninsula it is not too surprising since the three specimens positively
identified are immature birds and young possibly arrive earlier than do
adults. But, the immature specimens possibly are atypical individuals
of the resident population of _S. r. ridgwayi_.

Except for the immature individual from 5 km. WSW Puerto Juarez, all
specimens were taken in mist nets over the _cenote_ at Pisté where
_Petrochelidon fulva_ also was obtained.

    Specimens (7): [Male], 40694, imm., 16.2 gm., [Female], 40691,
    ovary inactive, 16.4 gm., molting--general body molt, 5th primaries
    and middle pair of rectrices ensheathed, [Female], 40712, imm.,
    14.5 gm., [Female], 40706, 14.8 gm., [Male], 40715, 16.4 gm.,
    [Male], 40710, 18.5 gm., molting--general body molt, 1st primaries
    and middle pair of rectrices ensheathed, all from Pisté, July 21
    and 25; [Male], 40720, imm., 15.5 gm. (August 1), 5 km. WSW Puerto
    Juarez.

_Hirundo rustica erythrogaster_ Boddaert: Barn Swallow.--Specimen (1):
[Female], 40721, imm., 7.3 gm. (August 18), apparently an early
migrant, 2 km. WSW Sisal.

_Iridoprocne albilinea_ (Lawrence): Mangrove Swallow.--Specimen (1):
[Female], 40722, imm. (July 7), Puerto Real, Isla del Carmen.

_Cissilopha yucatanica_ (Dubois): Yucatán Jay.--Heretofore, breeding
activity has been recorded only in March (Paynter, 1955a:217). All
specimens in my collection have extensively worn plumage and were
beginning to molt.

    Specimens (6): [Male], 40726, left testis 9 × 7 mm., right testis 4
    × 2 mm., brood patch, 122.3 gm., molting--1st and 2nd primaries
    ensheathed (July 10), 5 km. S Champotón; [Male], 40727, testis 5 ×
    3 mm., brood patch, 125.6 gm., molting--1st and 2nd primaries
    ensheathed (July 11), 5 km. SW Champotón; [Female], 40728, 109.8
    gm. (July 13), and sex? 40729, 109.5 gm. (July 15), 7-1/2 km. W
    Escárcega; [Female], 40730, imm., 110.3 gm. (July 21), Pisté;
    [Female], 40731, ovary inactive, brood patch refeathering, 121 gm.,
    molting--2nd and 3rd primaries ensheathed (August 16), 4 km. NNE
    Felipe Carrillo Puerto.

_Cyanocorax yncas maya_ (van Rossem): Green Jay.--There are records of
breeding by this species on the peninsula for April 28 and 29, and June
4 (Paynter, 1955a:215, 216).

    Specimens (4): [Male], 40740, testis 5 × 3 mm., 81.2 gm. (July 16),
    7-1/2 km. W Escárcega; [Female], 40739, juv., 62.3 gm. (July 21),
    [Male], 40737, 64.5 gm. (July 21), and [Female], 40738, 64.1 gm.
    (July 21), Pisté.

_Psilorhinus morio_ (Wagler): Brown Jay.--Specimens (3): [Female],
40742, 203.5 gm. (July 13), [Male], 40743, juv., 170 gm. (July 14),
7-1/2 km. W Escárcega; [Male], 40741, juv., 193.7 gm. (August 14), 4
km. NNE Felipe Carrillo Puerto.

_Thryothorus lucovicianus albinucha_ (Cabot): Carolina Wren.--This wren
formerly was considered to be a species (_T. albinucha_). In the light
of evidence presented by Lowery and Berrett (1963), it is advisable to
follow Paynter (1955a:219) and consider _albinucha_ to be a subspecies
of _T. ludovicianus_. The only previous evidence of breeding by this
species on the peninsula was a male having slightly enlarged gonads
taken by Paynter (1955a:219) on March 9.

    Specimen (1): [Male], 40754, juv., 16.8 gm. (August 14), 4 km. NNE
    Felipe Carrillo Puerto.

_Thryothorus maculipectus canobrunneus_ (Ridgway): Spotted-breasted
Wren.--According to Paynter (1955a:220) this species breeds from
mid-March to May 23. Gonads were moderately active in our specimens as
early as mid-July.

    Specimens (4): [Female], 40758, ovary (6 × 3 mm.) granular (July
    14), and [Male], 40757, testis 5 × 3 mm., 15.3 gm. (July 14), 7-1/2
    km. W Escárcega; [Female], 40755, ovary 6 × 3 mm. (ova to 1 mm.),
    12.7 gm. (July 21), Pisté; [Male], 40756, ovary 4 × 3 mm., 16.8 gm.
    (August 3), 4 km. WSW Puerto Juarez.

_Troglodytes musculus_ (Naumann): Southern House Wren.--Specimen (1):
[Female], 40760, juv. (August 2), 4 km. WSW Puerto Juarez.

_Troglodytes beani_ (Ridgway): Cozumel Wren.--Specimens (2): [Female],
40761, 13.3 gm. (August 9), and [Male], 40762, imm., 13.6 gm. (August
9), 3-1/2 km. N San Miguel, Isla Cozumel.

_Campylorhynchus yucatanicus_ (Hellmayr): Yucatán Wren.--This species
was abundant in the coastal scrub west of Sisal where some breeding
activity was noted. A few individuals were carrying nest material and
several were feeding young. There were many old and abandoned nests and
apparently the breeding season was nearly over. The only previous
breeding record is for March 19 when a newly completed nest was found
(Paynter, 1955a:218).

    Specimens (4): [Male], 40750, imm., 32.4 gm. (August 7), 1-1/2 mi.
    SW Sisal; [Female], 40751, imm., 31.2 gm. (August 18), 2 km. WSW
    Sisal; [Female], 40752, ovary 7 × 3 mm., 40 gm. (August 9), 4.3 km.
    WSW Sisal; [Female], 40753, 31.0 gm. (August 11), 6-1/2 km. WSW
    Sisal.

_Melanoptila glabrirostris cozumelana_ (Paynter): Black Catbird.--
Apparently the only previous record of breeding by this species was
Paynter's (1955b) mention of a male from Quintana Roo with enlarged
gonads on June 26. The three adults in the collection here reported on
were in nearly full reproductive activity.

    Specimens (4): [Male], 40764, imm., 40.5 gm. (August 8), [Female],
    40767, testis 8 × 4 mm., 42.0 gm., heavy fat (August 8), [Female],
    40765, ovary active (oviduct enlarged), brood patch, 35.2 gm.
    (August 10), and [Male], 40766, testis 9 × 6 mm., 35 gm. (August
    10), from 2-1/2-3-1/2 km. N San Miguel, Isla Cozumel.

_Mimus gilvus_ (Vieillot): Tropical Mockingbird.--The only breeding
record heretofore is by Paynter (1955a:226) of newly-fledged juveniles
taken on May 26 and 29. Gonads in our adults were moderately active;
feathers were extremely worn, but molting was not evident.

    Specimens (4): [Male], 40771, testis 9 × 6 mm., 51.0 gm. (July 9),
    5 km. S Champotón; [Female], 40770, ovary moderately active (ova to
    2 mm.), brood patch, 42 gm., moderate fat (August 9), 3-1/2 km. N
    San Miguel, Isla Cozumel; [Female], 40768, imm., 45.2 gm., moderate
    fat (August 18), 2 km. WSW Sisal; [Male], 40769, testis 10 × 5 mm.,
    51.8 gm. (August 9), 13 km. WSW Sisal. Mallophaga: _Myrsidea_ sp.,
    July 9.

_Toxostoma guttatum_ (Ridgway): Cozumel Thrasher.--Our specimen had
enlarged testes and seems to represent the first record of breeding
activity in the species.

    Specimen (1): [Male], 40772, testis 7 × 4 mm., 49.5 gm. (August
    10), 3-1/2 km. N San Miguel, Isla Cozumel.

_Turdus grayi_ Bonaparte: Clay-colored Robin.--Four adults were in full
breeding condition.

    Specimens (6): [Male], 40780, testis 13 × 8 mm., brood patch (July
    10), 5 km. S Champotón; [Female], 40781, ova to 8 mm., 79.6 gm.
    (July 15), 5 km. SW Escárcega; [Female], 40776, 61.3 gm. (July 21),
    Pisté; [Female], 40777, imm., 63.4 gm. (July 20), 6½ km. W Pisté;
    [Male], 40779, testis 14 × 8 mm., brood patch, 68.5 gm. (July 30),
    and [Male], 40778, testis 13 × 11 mm., 71.5 gm. (July 28), Pueblo
    Nuevo X-can.

_Polioptila caerulea_ (Linnaeus): Blue-gray Gnatcatcher.--A fledgling
taken at Pisté was barely flying with remiges and rectrices ensheathed
basally. Previous breeding records are for April 11 and 27 (Paynter,
1955a:231). A male taken on August 10 on Isla Cozumel had nearly
completed molting into winter plumage.

    Specimens (8): [Female], 40788, fledgling, 5.0 gm. (July 20), 6-1/2
    km. W Pisté; [Male], 40787, testis 2 × 1 mm., 5.6 gm. (July 21),
    [Male], 40785, juv., 5.8 gm. (July 22), and [Female], 40786, 5.6
    gm. (July 22), Pisté; [Female], 40791, juv., 5.6 gm. (August 8),
    [Male], 40790, juv., 5.8 gm. (August 8), [Female], 40789, 5.7 gm.
    (August 9), and [Male], 40792, 5.3 gm., molting--7th primaries
    ensheathed (August 10), from {2-1/2}-{3-1/2} km. N San Miguel, Isla
    Cozumel.

_Polioptila albiloris_ Lawrence: White-lored Gnatcatcher.--This species
was abundant in the arid scrub along the coast in the vicinity of
Sisal.

    Specimens (2): [Male], 40783, testis 1 mm., 6.2 gm. (August 7),
    1-1/2 mi. S Sisal; [Male], 40784, testis 1 mm., 5.8 gm. starting to
    molt--1st and 2nd primaries ensheathed (August 10), 13 km. WSW
    Sisal.

_Ramphocaenus rufiventris_ (Bonaparte): Long-billed Gnatwren.--Specimen
(1): [Female], 40793, imm. skull, 9.8 gm. (July 15), 7-1/2 km. W
Escárcega.

_Cyclarhis gujanensis insularis_ Ridgway: Rufous-browed Pepper-shrike.
--Specimen (1): [Male], 40794, testis 2 mm., 37.8 gm., molting--4th
primaries ensheathed (August 9), 4 km. N San Miguel, Isla Cozumel.

_Vireo bairdii_ (Ridgway): Cozumel Vireo.--Specimens (4): [Female],
40795, ovary inactive, 12.7 (August 8), [Male], 40796, testis 2 mm.,
12.6 gm., molting--3rd and 4th primaries ensheathed (August 10),
[Female], 40797, ovary inactive, 12.5 gm., molting--3rd primaries
ensheathed (August 10), and [Male], 47098, imm., 13.1 gm. (August 10),
from 2-1/2-3-1/2 km. N San Miguel, Isla Cozumel.

_Vireo pallens semiflavus_ (Salvin): Mangrove Vireo.--Paynter
(1955a:236) noted breeding by this species from April 7 through June.

    Specimens (2): [Female], 40800, ova to 3 mm., oviduct enlarged
    (July 8), Isla del Carmen; [Female], 40799, ovary inactive, 11.1
    gm., molting--4th primaries ensheathed (August 2), Isla Mujeres.

_Vireo flavoviridus flavoviridus_ (Cassin): Yellow-green Vireo.--Paynter's
(1955a:238) data indicate breeding in this species from late May
through June; our records indicate that the species breeds at least
through July.

    Specimens (12): [Male], 40812, testis 10 × 4 mm., 17.1 gm.,
    molting--1st, 2nd, and 3rd primaries ensheathed (July 17), and
    [Male], 40813, testis 7 × 4 mm., 18.2 gm. (July 17), 1 km. N, 13
    km. W Escárcega; [Female], 40803, ovary 9 × 5 mm., ova to 1 mm.,
    brood patch (July 21), [Male], 40805, testis 11 × 6 mm., 18.5 gm.
    (July 21), [Male], 40804, 18 gm. (July 21), and [Female], 40802,
    ovary slightly enlarged, molting--2nd and 3rd primaries ensheathed
    (July 21), all from Pisté; [Male], 40806, 17.5 gm., molting--1st
    primaries ensheathed (July 21), 6-1/2 km. W Pisté; [Female], 40808,
    ovary 5 × 3 mm., 17.4 gm. (July 28), [Male], 40807, testis 5 × 3
    mm., 17.7 gm., molting--3rd and 4th primaries ensheathed (July 28),
    [Male], 40809, testis 2 × 1 mm., 17.5 gm. (July 29), and [Male],
    40810, testis 3 × 2 mm., 18.7 gm., molting--1st, 2nd, 3rd, and 4th
    primaries ensheathed (July 30), from Pueblo Nuevo X-can; [Male],
    40811, testis 3 × 1 mm., 18.7 gm., molting--4th, 5th, and 6th
    primaries and middle pair of rectrices ensheathed (August 14), 4
    km. NNE Felipe Carrillo Puerto. Mallophaga: _Philopterus_ sp.
    July 21.

_Vireo magister_ (Lawrence): Yucatán Vireo.--Breeding on the peninsula
has not been recorded previously. A male, beginning to molt, taken on
August 10 on Isla Cozumel had enlarged testes, which were apparently
regressing.

    Specimens (3): [Female], 40814, ovary inactive, 17.7 gm. (August
    2), Isla Mujeres; sex? 40815, 19.5 gm. (August 9), and [Male],
    40816, testis 6 × 3 mm., 20.2 gm., molting--1st, 2nd, and 3rd
    primaries ensheathed (August 10), 3-1/2 km. N San Miguel, Isla
    Cozumel.

_Cyanerpes cyaneus carneipes_ (Sclater): Blue Honeycreeper.--Paynter
(1955a:283) collected specimens that were breeding in April. Testes
were fully enlarged in two August-taken specimens and courtship rituals
were observed in two pairs seen on August 3 at Puerto Juarez.

    Specimens (3): [Male], 40817, 15.5 gm. (July 21), 6-1/2 km. W
    Pisté; [Male], 40818, testis 12 × 6 mm., 12.1 gm. (August 3), 4 km.
    WSW Puerto Juarez; [Male], 40819, testis 8 × 6 mm., 11.6 gm.
    (August 14), 4 km. NNE Felipe Carrillo Puerto.

_Coereba flaveola caboti_ (Ridgway): Bananaquit.--Specimen (1):
[Female], 40820, ovary inactive, 5 × 3 mm., 11.0 gm., molting--1st and
2nd primaries ensheathed, 3rd and 4th primaries missing (August 10),
3-1/2 km. N San Miguel, Isla Cozumel.

_Dendroica petechia rufivertex_ (Ridgway): Yellow (Golden) Warbler.
--Specimens (5): [Female], 40831, ovary inactive, 8.0 gm. (August 8),
sex?, 40832, imm. (fresh, first winter plumage), 10 gm. (August 8),
[Female], 40830, ovary inactive, 10.0 gm., molting--4th and 5th
primaries ensheathed (August 9), [Female], 40833, ovary inactive, 8.5
gm. (August 9), and [Female], 40834, ovary inactive, 7.8 gm. (August
10), all from 3-1/2-4 km. N San Miguel, Isla Cozumel.

_Dendroica petechia bryanti_ (Ridgway): Yellow (Mangrove) Warbler.--
Previous records of breeding by this species are available for March 29
and 30 and May 16 (Paynter, 1955a:247). Breeding apparently continues
at least into July. An adult male with moderately enlarged testes
(probably regressing) was taken on July 7 at Zacatel, Campeche, and a
juvenile was obtained 13 km. WSW Sisal on August 10. The male at
Zacatal was in mangroves alongside the ferry landing (for the ferry
from Isla del Carmen) and seems to be the first specimen of this
subspecies recorded for the state.

    Specimens (7): [Male], 40829, testis 4 × 2 mm., 11.1 gm.,
    molting--1st, 2nd, and 3rd primaries ensheathed (July 7), Zacatal,
    Campeche; [Male], 40823, imm., 10.0 gm. (August 9), [Male], 40824,
    testis 1 mm., 13.0 gm., molting--4th and 5th primaries and middle
    three rectrices ensheathed (August 9), [Male], 40826, juv., 10.1
    gm. (August 10), [Male], 40827, imm. (fresh, first winter plumage),
    10.2 gm. (August 10), sex?, 40825, 10.3 gm. (August 10), and
    [Male], 40828, testis 2 mm., molting--7th, 8th, and 9th primaries,
    2nd, and 3rd secondaries and outer pair of rectrices ensheathed
    (August 11), all from 13 km. WSW Sisal.

_Seiurus motacilla_ (Vieillot): Louisiana Waterthrush.--Our specimen,
apparently an early migrant, was taken near the aguada at Rancho San
Miguel.

    Specimen (1): [Male], 40835, testis minute, 19.9 gm. (August 14), 4
    km. NNE Felipe Carrillo Puerto.

_Tangavius aeneus aeneus_ (Wagler): Red-eyed Cowbird.--A male having
enlarged testes taken on August 14 seems to be the first record of
breeding in the species for the peninsula.

    Specimens (2): [Male], 40838, testis 11 × 7 mm., 66.9 gm. (August
    14), and [Female], 40839, ovary 6 mm., 60 gm. (August 15), 4 km.
    NNE Felipe Carrillo Puerto.

_Cassidix mexicanus_ (Gmelin): Boat-tailed Grackle.--Specimen (1):
[Male], 40840, 223.3 gm. (July 9), 1 km. SW Puerto Real, Isla del
Carmen.

_Dives dives dives_ (Deppe): Sumichrast Blackbird.--This species
previously has been known to breed in May (Paynter, 1955a:263). The
specimens from July had moderately active ovaries.

    Specimens (2): [Female], 40842, ovary 8 × 4 mm., 92 gm. (July 11),
    5 km. SW Champotón; [Female], 40841, ovary 11 × 5 mm., 88.6 gm.
    (July 21), Pisté.

_Icterus prosthemelas_ (Strickland): Black-cowled Oriole.--Specimens
(2): [Female], 40843, ovary 5 × 3 mm., 28.8 gm., molting--extensive
body molt, 1st, 2nd, and 3rd primaries ensheathed (August 3), 4 km. WSW
Puerto Juarez; [Male], 40844, testis 2 × 1 mm., 31.0 gm., molting 1st,
2nd, 3rd, and 4th primaries ensheathed (August 16), 4 km. NNE Felipe
Carrillo Puerto.

_Icterus mesomelas_ (Wagler): Yellow-tailed Oriole.--Our specimens
extend the known breeding season; previous records are for April and
May (Paynter, 1955a:265).

    Specimens (4): [Male], 40848, testis 11 × 5 mm. (July 14), 7-1/2
    km. W Escárcega; [Male], 40846, juv. (rectrices and remiges
    ensheathed basally), 30.3 gm. (July 29), and [Male], 40847, testis
    12 mm., 38.0 gm. (July 29), Pueblo Nuevo X-can; [Female], 40845,
    ovary 6 × 3 mm., 32.5 gm. (August 4), 4 km. WSW Puerto Juarez.

_Icterus auratus_ Bonaparte: Orange Oriole.--Paynter (1955a:266)
reported breeding specimens taken in April and May. Two males taken in
late July had fully enlarged testes.

    Specimens (2): [Male], 40849, testis 10 × 6 mm., 32.5 gm. (July
    28), Pueblo Nuevo X-can; [Male], 40850, testis 11 × 7 mm., 33.0 gm.
    (July 30), 1-1/2 km. S, 1 km. E Pueblo Nuevo X-can.

_Icterus gularis_ (Wagler): Black-throated Oriole.--Breeding in this
species was reported by Paynter (1955a:267) only for the month of
April. Breeding was apparently nearing an end in late July at Pisté,
where several juveniles were taken. Adult males had moderately enlarged
testes.

    Specimens (8): [Male], 40858, testis 5 × 3 mm., 67.2 gm. (July 20),
    6-1/2 km. W Pisté; [Male], 40853, 59.0 gm. (July 21), [Female],
    40851, imm., 49.9 gm. (July 21), [Male], 40852, 56.4 gm. (July 21),
    [Female], 40855, imm., 49.9 gm. (July 22), [Female], 40856, ovary
    inactive, 50.0 gm. (July 22), [Male], 40854, testis 6 × 4 mm., 63.8
    gm. (July 22), and [Male], 40857, juv. (all rectrices and remiges
    ensheathed basally), 30.4 gm. (July 27), all from Pisté.

_Icterus cucullatus_ Nelson: Hooded Oriole.--This species has not
heretofore been recorded as breeding on Isla Cozumel; testes were
nearly fully enlarged but probably regressing in the only specimen
taken there. It had been banded (USF&WS no. 601-87003) on the island in
1961 as an adult. According to Paynter (1955a:269) there are no
breeding records for this species on the mainland later than April,
March 25 being the earliest date. The species was observed nesting on
Isla del Carmen and adult males taken there and 5 km. S Champotón in
early July were in full breeding condition.

    Specimens (6): [Male], 40863, testis 11 × 7 mm., 26.3 gm. (July 8),
    [Female], 40864, 31.4 gm. (July 8), and [Male], 40862, testis 11 ×
    5 mm., 24.7 gm. (July 8), 1 km. SW Puerto Real, Isla del Carmen;
    [Male], 40860, 26.5 gm. (July 9), and [Male], 40861, testis 10 × 5
    mm., 20.9 gm. (July 11); 5 km. S Champotón; [Male], 40859, testis 8
    × 5 mm., molting--7th primaries ensheathed, 27.0 gm. (August 8),
    3.5 km. N San Miguel, Isla Cozumel.

_Tanagra affinis affinis_ Lesson: Lesson Euphonia.--Specimens (2):
[Female], 40866, 8.8 gm. (July 22), Pisté; [Male], 40865, testis 3 × 2
mm., 10.0 gm. (August 3), 4 km. WSW (Aeropuerto) Puerto Juarez.

_Tanagra lauta lauta_ Bangs and Penard: Thick-billed
Euphonia.--According to Paynter (1955a:272), the only breeding record
previously available is that of a male having slightly enlarged testes
on February 12. Males taken on July 15 and on August 14 had fully
enlarged testes; the gonads of several other specimens were apparently
regressing, two specimens had begun to molt, and juveniles were molting
into first winter plumage.

    Specimens (9): [Male], 40874, testis 7 × 4 mm. (July 15), and
    [Female], 40875, ova to 1 mm. (July 15), 7-1/2 km. W Escárcega;
    [Male], 40869, testis 6 × 4 mm., 14.5 gm. (August 14), [Male],
    40870, testis 2 mm., 14.5 gm., molting--5th primaries ensheathed
    (August 14), [Male], 40867, imm., 12.6 gm. (August 14), [Female],
    40868, imm., 14.4 gm. (August 14), [Male], 40871, testis 2 mm.,
    14.4 gm., molting--2nd, 3rd, and 4th primaries ensheathed (August
    14), [Female], 40872, ovary granular, 7.8 gm. (August 14), and
    [Female], 40873, ovary granular, 13.0 gm. (August 15), all taken 4
    km. NNE Felipe Carrillo Puerto.

_Thraupis abbas_ (Deppe): Yellow-winged Tanager.--Paynter (1955a:273)
reported breeding in this species in late April and late June. Gonads
in our specimens were moderately active.

    Specimens (2): [Male], 40877, testis 6 × 4 mm., 43.0 gm.,
    molting--1st and 2nd primaries ensheathed (July 15), 1 km. N, 13
    km. W Escárcega; [Female] 40876, ovary 7 × 4 mm., (ova to 1 mm.),
    42.1 gm. (July 29), Pueblo Nuevo X-can.

_Spindalis zena benedicti_ Ridgway: Stripe-headed Tanager.--Two males
in advanced molt but with enlarged gonads were taken on August 9 and 10
and seem to be the first records indicating breeding in this species on
Isla Cozumel.

    Specimens (3): [Male], 40878, testis 9 × 7 mm., 32 gm.,
    molting--5th primaries and middle pair of rectrices ensheathed
    (August 9), [Male], 40880, testis 5 × 3 mm., 30.0 gm.,
    molting--3rd, 4th, 5th primaries and middle two pairs of restrices
    ensheathed (August 10), and [Female], 40879, ovary inactive, 28.1
    gm., molting--remiges are new; secondary coverts ensheathed (August
    10), 3-1/2 km. N San Miguel, Isla Cozumel.

_Piranga roseogularis_ (Cabot): Rose-throated Tanager.--Breeding has
been previously recorded from March 17 through May 11 (Paynter,
1955a:276). Our only specimen, a male in advanced molt, had enlarged
(regressing) testes.

    Specimen (1): [Male], 40881, testis 7 × 5 mm., 24.2 gm.,
    molting--4th and 5th primaries ensheathed (August 15), 4 km. NNE
    Felipe Carrillo Puerto.

_Habia gutturalis_ (Sclater): Red-throated Ant-tanager.--The only
breeding records previously available for this species on the peninsula
are for May 18 (Paynter, 1955a:280) and June 25 (Paynter, 1955b).
Specimens taken between July 14 and August 2 were in full breeding
condition. A male (40882) and female (40883) taken 7-1/2 km. W
Escárcega were known to be mated. Plumages in all specimens are worn
and for that reason specimens were not identified to subspecies.

    Specimens (6): [Male], 40882, testis 14 × 9 mm., 38.9 gm. (July
    14), [Female], 40883, ovary 5 × 5 mm., 29.0 gm. (July 14), and
    [Male], 40887, testis 10 × 7 mm. (July 16), 7-1/2 km. W Escárcega;
    [Male], 40885, juv. (rectrices and remiges ensheathed basally)
    (July 28), and [Female], 40886, ovary moderately active, 30.5 gm.,
    molting--2nd primaries ensheathed (July 28), Pueblo Nuevo X-can;
    [Male], 40884, testis 15 × 8 mm. (August 2), 4 km. WSW Puerto
    Juarez.

_Saltator atriceps_ (Lesson): Black-headed Saltator.--Previously,
breeding has been noted in this species in February, March, and April
(Paynter, 1955a:284). A male taken on July 16 was in full breeding
condition.

    Specimens (3): [Male], 40895, testis 15 × 9 mm., 80.4 gm. (July
    16), and [Female], 40896, 73.5 gm. (July 17), 7-1/2 km. W
    Escárcega; [Male], 40894, 71.6 gm. (July 29), Pueblo Nuevo X-can.

_Saltator coerulescens_ (Vieillot): Gray Saltator.--The only previous
breeding record for this species is for April 26. Our one specimen, No.
40897, a juvenal male barely able to fly, taken on July 21 at Pisté,
weighed 43.8 grams.

_Richmondena cardinalis_ (Linnaeus): Cardinal.--The only record of
breeding previously reported is of a male with enlarged testes taken on
June 4 (Paynter, 1955a:287). Adult males with enlarged testes were
obtained on July 11 and August 10, and three juveniles were taken
southwest of Sisal on August 10, 16, and 18.

    Specimens (7): [Male], 40903, testis 9 × 7 mm., 39.7 gm. (July 11),
    and [Female], 40904, 34.0 gm. (July 11), 5 km. S Champotón; [Male],
    40898, testis 7 × 4 mm., 33.8 gm. (August 10), and [Female], 40899,
    juv. (rectrices and remiges ensheathed basally), 32.8 gm. (August
    10), 13 km. WSW Sisal; [Male], 40900, fledgling, 18.4 gm. (August
    18), 2 km. WSW Sisal; [Female], 40901, ovary granular, 37.4 gm.,
    molting--1st primaries ensheathed (August 15), and [Male], 40902,
    imm., 34.0 gm. (August 16), 4 km. NNE Felipe Carrillo Puerto.

_Cyanocompsa parellina_ (Bonaparte): Blue Bunting.--Specimens (2):
[Male], 40906, imm. (July 15), and [Male], 40905, testis 10 × 7 mm.,
15.2 mm. (July 15), 7-1/2 km. W Escárcega.

_Tiaris olivacea pusilla_ (Swainson): Yellow-faced Grassquit.--The only
records of breeding, thus far, are by Paynter (1955a:291) for March 12
and June 14. A male (40907) taken 4 km. NNE Felipe Carrillo Puerto on
August 14 had fully enlarged testes (8 × 5 mm.).

_Tiaris olivacea intermedia_ (Ridgway): Yellow-faced Grassquit.--Although
females taken on Isla Cozumel exhibited no reproductive activity, two
males had moderately enlarged testes. These seem to be the first
records of breeding in this subspecies, which is endemic to Isla
Cozumel.

    Specimens (5): [Male], 40908, testis 6 z 4 mm., 10.5 gm. (August
    8), [Female], 40912, ovary inactive, 9.5 gm. (August 8), [Female],
    40909, ovary inactive, 10.4 gm. (August 9), [Male], 40910, testis 5
    × 3 mm., 11.5 gm., molting--1st primaries ensheathed (August 9),
    and [Male], 40911, 11.5 gm. (August 10), all from {2-1/2}-{3-1/2}
    km. N San Miguel, Isla Cozumel.

_Sporophila torquiola morelleti_ (Bonaparte): White-collared Seedeater.
--Breeding is known for this species in May and a male collected on
September 2 was in breeding condition (Paynter, 1955a:293). Our records
seem to be the first for the summer. Specimens taken in July and August
were breeding.

    Specimens (7): [Female], 40918, 9.2 gm. (July 8), 1 km. SW Puerto
    Real, Isla del Carmen; [Male], 40919, testis 7 × 6 mm., 8.2 gm.
    (July 15), 7-1/2 km. W Escárcega; [Female], 40913, ovary inactive,
    7.9 gm. (August 4), 4 km. WSW Puerto Juarez; [Male], 40914, testis
    minute, 7.8 gm. (August 14), [Female], 40915, ova to 6 mm. (August
    15), [Female], 40917, ovary moderately active, 7.0 gm. (August 16),
    and [Male], 40916, testis 7 × 5 mm., 7.6 gm. (August 16), 4 km. NNE
    Felipe Carrillo Puerto.

_Volatinia jacarina splendens_ (Vieillot): Blue-black Grassquit.--The
only previous record of breeding is a male having slightly enlarged
testes taken on June 1 (Paynter, 1955a:293). Our specimens showed
various stages of reproductive activity when taken on July 10.

    Specimens (6): [Male], 40926, 8.9 gm. (July 10), and [Male], 40925,
    testis 2 × 1 mm., 8.5 gm. (July 10), 1 km. S Puerto Real, Isla del
    Carmen; [Male], 40924, testis 4 × 2 mm. (July 10), [Male], 40922,
    testis 6 × 4 mm., 8.3 gm. (July 10), [Female], 40923, ova to 2 mm.,
    10.3 gm. (July 10), and [Male], 40921, 8.2 gm. (July 10), 5 km. S
    Champotón.

_Arremonops rufivirgata verticalis_ Ridgway: Olive Sparrow.--Apparently
the only previous record of breeding was the laying female on June 14
reported by Paynter (1955a: 294). Males collected in July and August
had enlarged testes; a juvenile, barely able to fly, was taken on
August 14. Two specimens were beginning to molt.

    Specimens (9): [Female], 40932, ova to 1 mm., 20.8 gm. (July 21),
    and [Male], 40933, testis 8 × 6 mm., 21.2 gm. (July 21), Pisté;
    [Female], 40930, ovary moderately active, 23.2 gm. (July 26), and
    [Male], 40931, imm., 22.7 gm. (July 26), 3-1/2 km. N Pisté; [Male],
    40934, testis 6 × 4 mm., 24.5 gm., molting--1st and 2nd primaries
    ensheathed (August 14), [Male], 40935, juv. (remiges and rectrices
    ensheathed basally), 17.7 gm. (August 14), [Female], 40936, imm.,
    25.0 gm (August 14), [Female], 40937, ovary granular, 22.6 gm.,
    molting--2nd primaries ensheathed (August 15), and [Male], 40938,
    testis 7 × 5 mm. (August 15), 4 km. NNE Felipe Carrillo Puerto.

_Arremonops chloronota chloronota_ (Salvin): Green-backed Sparrow.--
Evidence presented by Monroe (1963) indicates that _A. chloronota_ and
_A. conirostris_ are not conspecific. Specimens collected in breeding
condition in July seem to be the first breeding records of this species
on the peninsula.

    Specimens (7): [Female], 40942, ova to 3 mm., 29.6 gm. (July 11), 5
    km. S Champotón; [Male], 40944, testis 10 × 6 mm., 27.0 gm. (July
    14), [Male], 40943, testis 5 × 3 mm., 23.1 gm. (July 14), and
    [Male], 40945, testis 7 × 4 mm., 25.5 gm. (July 15), 5-{7-1/2} km.
    W Escárcega; sex? 40939, 22.9 gm. (July 20), 6-1/2 km. W Pisté;
    [Male], 40940, imm., 21.5 gm. (August 4), 4 km. WSW Puerto Juarez;
    [Female], 40941, 26.5 gm., extensive body molt, (August 15), 4 km.
    NNE Felipe Carrillo Puerto.

TABLE 2. An Alphabetical List of Species of Mallophaga Removed from
Birds Collected on the Yucatán Peninsula in 1962.

  ========================================================================
                                   |                        |KU Catalogue
            MALLOPHAGA             |         Hosts          |Nos. of
                                   |                        |specimens
                                   |                        |  of hosts
  ------------------------------------------------------------------------
  _Actornithophilus ochraceus_     |Snowy Plover            |40426, 40431
  _Amyrisidea spicula_             |Chachalaca              |Specimen not
                                   |                        |preserved
  _Austromenopon sachlebeni_       |Willet.                 |40441
  _Carduiceps zonarius_            |Sanderling              |40443, 40444
  _Ciconiphilus obscurus_          |American Egret          |40402
  _Colpocephalum foetens_          |Black Vulture           |Specimen not
                                   |                        |preserved
  _Colpocephalum megalops_         |King Vulture            |40403
  _Columbicola macrourae_          |Zenaida Dove            |40399
  _Columbicola_ sp.                |Red-billed Pigeon       |40457
  _Craspedorrhy_ sp.               |Gray Hawk               |40415
  _Lunaceps holophaeus actophilus_ |Sanderling              |40444
  _Myrsidea_ sp.                   |Tropical Mockingbird    |40771
  _Myrsidea_ sp.                   |Cave Swallow            |40690, 40704
  _Myrsidea_ sp.                   |Sulphury Flat-billed    |
                                   |  Flycatcher            |40685
  _Philopterus excisus_            |Cave Swallow            |40697
  _Philopterus_ sp.                |Sulphury Flat-billed    |
                                   |  Flycatcher            |40682, 40686
  _Philopterus_ sp.                |Great Kiskadee          |40664
  _Philopterus_ sp.                |Turquoise-browed Motmot |Specimen not
                                   |                        |preserved
  _Philopterus_ sp.                |Yellow-green Vireo      |40804
  _Penerirmus_ sp.                 |Red-capped Green        |
                                   |  Woodpecker            |40594
  _Quadraceps assimilis major_     |Snowy Plover            |40431
  _Quadraceps assimilis major_     |Wilson Plover           |40432, 40436
  _Quadraceps carrikeri_           |Willet                  |40442
  _Quadraceps ravus_               |Spotted Sandpiper       |40438
  _Quadraceps_ sp.                 |Laughing Gull           |40449
  _Saemundssonia brevicornis_      |Cabot Tern              |40452




SUMMARY


Locality records are given for each of 136 species of birds represented
by 493 specimens and sight records are given for eight additional
species.

The Yellow-headed Vulture is reported apparently for the first time
from the peninsula. The specimens of the Streak-headed Woodhewer and
the Louisiana Waterthrush are the second ones of each species taken on
the peninsula. The Purple Martin taken on August 14, the Barn Swallow
on August 18, and the Louisiana Waterthrush on August 14 represent
earliest known autumn dates for these transients.

Evidence for breeding is given for 20 species for the first time and
extensions of the known breeding seasons are presented for 41 species.

Fourteen genera, representing about 19 species, of Mallophaga are
reported for 20 different species of bird hosts.

At Pisté and Puerto Juarez, species of birds such as the Blue
Honeycreeper and the Red-capped Manakin, normally thought of as
characteristic of more humid areas, were found breeding in numbers near
_cenotes_. However, they were not seen to venture far into the
surrounding deciduous forest. The availability of suitable habitat
brought on by the rainy season and the regular occurrence of _cenotes_
helps to explain the presence of such species far outside the Rain
Forest zone.




LITERATURE CITED


BLAKE, E. R.

1953. Birds of Mexico a guide for field identification. Univ. of
Chicago Press, Chicago, xxix + 644 pp.


BRODKORB, P.

1943. Birds from the gulf lowlands of southern Mexico. Misc. Publ.,
Mus. Zool., Univ. Michigan., 55:1-88, January 30.


FRIEDMANN, H., GRISCOM, L., and MOORE, R. T.

1950. Distributional check-list of the birds of Mexico Part I. Pac.
Coast Avif., 29:1-202, June 30.


JOHNSTON, R. F.

1962. The taxonomy of pigeons. Condor, 64:69-74, January 30.


LOWERY, G. H., JR. and BERRETT, D. G.

1963. A new Carolina Wren (Aves: Troglodytidae) from southern Mexico.
Occas. Papers Mus. Zool., Louisiana St. Univ., 24:1-3, December 20.


MILLER, A. H., FRIEDMANN, H., GRISCOM, L.,
and MOORE, R. T.

1957. Distributional check-list of the birds of Mexico Part II. Pac.
Coast Avif., 33:1-436, December 20.


MONROE, B. L., JR.

1963. Notes on the avian genus _Arremonops_ with description of a new
subspecies from Honduras. Occas. Papers Mus. Zool., Louisiana St.
Univ., 28:1-12.


PAYNTER, R. A., JR.

1955a. The ornithogeography of the Yucatán Peninsula. Bull. Peabody
Mus. Nat. Hist., 9:1-347.

1955b. Additions to the ornithogeography of the Yucatán Peninsula.
Postilla, no. 22, 4 pp. (unpaged).


RIDGWAY, R.

1914. Birds of North and Middle America: a descriptive catalogue ...
Bull. U.S. Nat. Mus., 50:xx+1-882, 35 pls., April 8.


SELANDER, R. K. and GILLER, D. R.

1963. Species limits in the woodpecker genus _Centurus_ (Aves). Bull.
Amer. Mus. of Nat. Hist., 124:215-273.


SKUTCH, A.

1947. Life history of the turquoise-browed motmot. Auk, 64:201-217,
April.


STORER, R. W.

1961. Two collections of birds from Campeche, Mexico. Occas. Papers
Mus. Zool., Univ. Michigan, 621:1-20, August 15.


TRAYLOR, M. A., JR.

1941. Birds from the Yucatán Peninsula. Publ. Field Mus. Nat. Hist.,
Zool. Ser., 24:195-225.


WEBSTER, J. D.

1963. A revision of the rose-throated becard. Condor, 65:383-399, 3
figs., 8 tables, September 27.


WETMORE, A.

1950. The identity of the American vulture described as _Cathartes
burrovianus_ by Cassin. Jour. Wash. Acad. Sci., 40:415-417.


_Transmitted July 11, 1967._