Chapter I: Part 1

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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 Yucatan Peninsula has received considerable attention by ornithologists. The most valuable contribution is Paynter's "The Ornithogeography of the Yucatan 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 Yucatan 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 Escarcega, 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 Piste, Yucatan, by Luis V. Polanco. The field party benefited also from arrangements and helpful suggestions made by Eduardo C. Welling of Merida 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 Macias Arellano, Departamento de la Fauna Silvestre, Direccion General de Caza, Mexico, D.F., generously provided the necessary permits for collecting vertebrates.

PHYSICAL FEATURES

The Yucatan 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 Yucatan and the sparsely settled Territory of Quintana Roo, plus parts of British Honduras and the Peten 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 Yucatan 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 deg. to 98 deg. 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 Yucatan. 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 Yucatan 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 Yucatan not in the Scrub zone, northern Campeche, and a thin strip a few kilometers wide in Quintana Roo along the Yucatan-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 Champoton, Campeche, Isla Cozumel and Puerto Juarez, Quintana Roo, and Piste, Yucatan.

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 Escarcega, 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 Yucatan 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 Chichen-Itza 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

Champoton.--Lat. 19 deg. 21' N, long. 90 deg. 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_.

Escarcega.--Lat. 18 deg. 37' N, long. 90 deg. 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 deg. 43' N, long. 91 deg. 41' W, sea level to two
meters. An island in the mouth of Laguna de Terminos. 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 deg. 35' N, long. 88 deg. 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 deg. 27' N, long. 86 deg. 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 deg. 12' N, long. 86 deg. 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.

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

Puerto Juarez.--Lat. 21 deg. 10' N, long. 86 deg. 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.

Yucatan

Piste.--Lat. 20 deg. 42' N, long. 88 deg. 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 Chichen-Itza.

Sisal.--Lat. 21 deg. 10' N, long. 90 deg. 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, Direccion General de Caza, Mexico, 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 Champoton. 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 Nuevo 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 Champoton, 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 Mexico. 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 Yucatan 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 Champoton.

_Chondrohierax uncinatus uncinatus_ (Temminck): Hook-billed Kite.--A pair was seen 5 km. S Champoton 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 Yucatan and Campeche in winter and allocated the specimens to the nominate form.

At Piste, 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 x 5 mm., 215.0 gm. (July
10), 5 km. S Champoton; [Male], 40405, nestling, 117.6 gm. (July
24), Piste.

_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 Escarcega; [Male], 40413, 279
gm. (July 17) 1 km. N, 13 km. W Escarcega; [Male], 40407, testis 5
x 2 mm., 254.7 gm. (July 23), Piste: [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 Escarcega 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 x 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 Champoton, 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 x 9 mm., 408.5 gm. (July 16), 7-1/2 km. W Escarcega. 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 x 5 mm., 119.6 gm. (August
18), and [Male], 40419, testis 11 x 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 x 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 x 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 x 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 x 1 mm., 57.5 gm., heavy fat
(August 9), [Female], 40444, ovary granular 6 x 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_ (Mueller): 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 x 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 Escarcega, 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 x 5
mm. (July 15), 6-{7-1/2} km. W Escarcega; [Male], 40453, testis 15
x 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 Escarcega, probably because of the tall forest and lack of clearings there.

Specimens (5): [Male], 40461, testis 10 x 5 mm., 40.9 gm. (August
10), 2 km. WSW Sisal; [Male], 40460, testis 6 x 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 x 5 mm., 50.0 gm (July 8), [Male], 40469,
testis 10 x 5 mm., 65.5 gm. (July 8), [Female], 40470, ova to 3
mm., 51.6 gm. (July 8) and [Male], 40471, testis 9 x 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 Chapoton; [Male],
40473, testis 8 x 5 mm., 53.0 gm. (July 17), 1 km. N, 13 km. W
Escarcega; [Female], 40465, ova to 21 mm., 51.8 gm. (July 28);
Pueblo Nuevo X-can; [Male], 40466, testis 8 x 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 x 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 Escarcega 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 Escarcega; [Female],
40477, ovary 12 x 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 x 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 x 8 mm., 144.7 gm. (July
29), Pueblo Nuevo X-can.

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

Specimens (2): [Male], 40481, testis 3 x 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 Champoton. 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 x 2 mm., 229.1 gm.,
molting--extensive body molt, 6th primaries ensheathed (July 9),
and [Female], 40484, ovary 13 x 9 mm. (inactive), 209.0 gm.,
molting--extensive body molt, wing molt complete (July 11), 5 km. S
Champoton; [Male], 40485, testis 5 x 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 Escarcega where large flocks were seen every evening. A specimen of _A. albifrons_ was taken south of Champoton where this species occurred in large flocks with _A. xantholora_. One specimen was taken from a small flock near Chichen-Itza.

Specimens (5): [Male], 40487, testis 8 x 4 mm., 210.0 gm. (July
10), 5 km. S. Champoton; [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 Escarcega; [Female], 40486, ovary inactive, 176.0 gm.
(July 27), 2 km. E Chichen-Itza.

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

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

_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 Champoton, Piste, 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 x 6 mm., 99.6 gm. (July 14),
and [Female], 40494, 90.0 gm. (July 14), 7-1/2 km. W Escarcega;
[Male], 40492, testis 5 x 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 Piste 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), Piste; [Male], 40498, testis 11 x 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 x 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 x 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 x 4 mm.), was taken at night on July 16 from a mist net stretched across a small trail 1 km. N, 13 km. W Escarcega.

_Nyctibius griseus mexicanus_ Nelson: Mexican Potoo.--One specimen was taken at night 7-1/2 km. W Escarcega 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 Escarcega;
[Female], 40504, ovary 13 x 4 mm. (inactive), 265 gm. (August 16),
and [Male], 40503, testis 5 x 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 x 3 mm., 57.3 gm. (August
1), 5 km. WSW Puerto Juarez; [Female], 40507, ovary 4 x 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 Piste on July 21. Therefore the reproduction period seems to be longer than Paynter's (1955a:141) data suggested.

Specimens (5): [Male], 40512, testis 7 x 3 mm., 75 gm. (July 10), 5
km. S Champoton; [Female], 40508, juv. (remiges and rectrices
ensheathed basally), 44.2 gm. (July 21), Piste; sex? 40510, 55.5
gm. (August 8), and [Male], 40509, testis 3 x 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 x 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 x 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 Escarcega 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), Piste; [Female], 40529, ovary inactive, 2.4 gm.
(July 26), 3-1/2 km. N Piste.

_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
Escarcega; [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): Yucatan 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 x 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 x 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 Escarcega; [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 Yucatan 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 Champoton, Campeche, 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 Champoton and Escarcega. 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 Chichen-Itza; adults with enlarged gonads and brood patches and juveniles were taken at Piste as late as July 21.

Specimens (19): [Male], 40565, brood patch, 59.4 gm. (July 9),
[Male], 40564, testis 8 x 4 mm., brood patch, 68.0 gm. (July 9),
[Male], 40566, 74 gm. (July 9), [Female], 40567, juv. (July 9),
[Male], 40568, testis 5 x 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 Champoton; [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),
Piste. Eight nestlings (40569-76) that were taken from burrows at 5
km. S Champoton 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 Champoton 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 Champoton 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
Champoton.

_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 x 2 mm., 155 gm. (July 16),
7-1/2 km. W Escarcega; [Male], 40582, testis 10 x 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 x 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 Escarcega, 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 x 3 mm., 414.5 gm. (July 14), [Female], 40590, ovary 11
mm., 347.4 gm. (July 15), [Male], 40591, testis 5 x 3 mm., 371 gm.
(July 15), [Male], 40593, testis 6 x 3 mm., 422.2 gm. (July 16) and
[Male], 40592, 401.5 gm. (July 16), 6-7-1/2 km. W Escarcega;
[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 x 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 Escarcega.

_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 x 3 mm. (enlarged oviduct), 76.4 gm. (July 10), 1 km. S
Puerto Real, Isla del Carmen; [Male], 40599, testis 6 x 8 mm.,
101.3 gm. (July 10), and [Male], 40600, 86.0 gm. (July 11), 5 km. S
Champoton; [Male], 40603, testis 5 x 3 mm. (July 14), and [Female],
40604, ovary 6 x 4 mm. (ova to 1 mm.), brood patch (July 16), 7-1/2
km. W Escarcega; sex? 40596, molting, much visceral fat, 79.0 gm.
(July 22), Piste; [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): Yucatan 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 x 4 mm. (July 10); [Female],
40607, 39.5 gm. (July 10), 5 km. S Champoton; [Male], 40609, testis
inactive, 35.8 gm., moderate visceral fat (July 17), 1 km. N, 13
km. W Escarcega; [Female], 40606, ovary 6 x 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), Piste; 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 x 1 mm., 35.7 gm., molting--5th primaries and middle pair of rectrices ensheathed (July 17), 1 km. N, 13 km. W Escarcega.

_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 x 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), Piste; [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 x 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 x 1 mm., 26.6 gm., molting--6th
primaries ensheathed, middle pair of rectrices are new (July 17), 1
km. N, 13 km. W Escarcega.

_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 x 5 mm. (inactive), 26 gm. (August 14), 4 km. NNE Felipe Carrillo Puerto.