Produced by Chris Curnow, Joseph Cooper, Diane Monico, and
the Online Distributed Proofreading Team at
http://www.pgdp.net
UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY
Volume 12, No. 7, pp. 309-345, pls. 5-8.
June 18, 1962
Vertebrates from the Barrier Island
of Tamaulipas, Mexico
BY
ROBERT K. SELANDER, RICHARD F. JOHNSTON,
B. J. WILKS, AND GERALD G. RAUN
UNIVERSITY OF KANSAS
LAWRENCE
1962
UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY
Volume 12, No. 7, pp. 309-345, pls. 5-8.
June 18, 1962
Vertebrates from the Barrier Island
of Tamaulipas, Mexico
BY
ROBERT K. SELANDER, RICHARD F. JOHNSTON,
B. J. WILKS, AND GERALD G. RAUN
UNIVERSITY OF KANSAS
LAWRENCE
1962
UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY
Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Theodore H. Eaton, Jr.
Volume 12, No. 7, pp. 309-345
Published June 18, 1962
UNIVERSITY OF KANSAS
Lawrence, Kansas
PRINTED BY
JEAN M. NEIBARGER, STATE PRINTER
TOPEKA, KANSAS
1962
29-3002
Vertebrates from the Barrier Island of Tamaulipas, Mexico
BY
ROBERT K. SELANDER, RICHARD F. JOHNSTON, B. J. WILKS, and
GERALD G. RAUN
Lying between the Gulf of Mexico and the Laguna Madre de Tamaulipas is
a narrow barrier island extending from the delta of the Rio Grande
south for 140 miles to within 185 miles of Tampico, Tamaulipas (Plate
5). This island, like most of coastal Tamaulipas, has been all but
neglected by zoological collectors. Consequently, little is known of
the kinds, distribution, and seasonal status of the vertebrates
occurring there. The present paper is a report on land vertebrates
collected and observed on the northern part of the barrier island of
Tamaulipas from July 6 to 10, 1961. Our collection, which has been
deposited in the Museum of Natural History, The University of Kansas,
consists of 63 reptiles, 33 mammals, and 97 birds (58 skins, 19
skeletons, and 20 alcoholics).
Acknowledgments
We are especially indebted to Dr. Charles H. Simpson of Sinton, Texas,
who generously placed at our disposal his truck, a four-wheel drive
"Land Rover," without which travel on the island would have been
difficult. We also acknowledge a loan of field equipment provided by
Dr. Clarence Cottam, Director of the Welder Wildlife Research
Foundation, Sinton, Texas.
Financial support for the present research was provided by grants from
the National Science Foundation to The University of Texas (G 15882)
and to The University of Kansas (G 10043).
Permits to collect vertebrates in Mexico were supplied by Ing. Luis
Macias Arellano, El Director General, Departamento de Conservacion de
la Fauna Silves, Mexico, D. F.
We are indebted to Dr. Richard H. Manville for arranging a loan of
specimens of _Geomys personatus tropicalis_ in the United States
National Museum. Dr. Marshall Johnston kindly identified specimens of
plants from the barrier island. Several bones of birds and mammals were
identified by Dr. Pierce Brodkorb and Dr. E. L. Lundelius. Mr. J. Knox
Jones identified some of the mammalian material, and Dr. W. E. Duellman
verified the identifications of the lizards; we thank all of these men
for their willing assistance.
The Ecological Setting
The barrier island of Tamaulipas geologically and ecologically
resembles Padre Island, of the Gulf coast of lower Texas, north of the
mouth and delta of the Rio Grande. South of the delta, the island in
Tamaulipas is a narrow strip of sand less than a mile in average width
and is broken by a series of narrow inlets or "passes" through which
water from the Gulf of Mexico mingles with that of the Laguna Madre de
Tamaulipas. The passes are subject to recurrent opening and closing.
North of the mouth of the Rio Soto la Marina, eight passes are
designated by local fishermen, but only three, the Third, Fourth, and
Fifth, were open at the time of our visit.
The Laguna Madre de Tamaulipas is described by Hildebrand (1958) in
connection with a preliminary study of the fishes and invertebrates
there. The average depth is probably less than 70 cm. and the waters
are hypersaline. In the time of the recent drought in Texas and
northeastern Mexico, salinity varied from 108 to 117 parts per thousand
in the northern part of the laguna near Arroyo del Tigre (measurements
taken in March, 1955) to from 39 to 48 parts per thousand in the
southern part near Punta Piedras (measurements taken in October and
November, 1953, and in March, 1954). Discussions of the geologic
history, ecology, and zoogeography of the lagoons of the Gulf coast of
the United States are given by Hedgpeth (1947; 1953).
Localities in coastal Tamaulipas mentioned in the text of this paper
are shown on Plate 5.
The principal animal habitats are found in three vegetational
associations (plates 6 and 7). On flats and low dunes lying between,
and partly sheltered by, larger active dunes, small clumps of _Croton
punctatus_ and a sedge (_Fimbristylis castanea_) are the only
conspicuous plants. Near the western edge of the dunes, _Ipomoea
pescaprae_ var. _emarginata_ is mixed with _Croton_, and there are
scattered clumps of shrubby wolf-berry (_Lycium carolinianum_ var.
_quadrifidum_), and mesquite (_Prosopis juliflora_).
The dunes are relatively stabilized on the western side of the island,
and there we found moderately dense stands of mesquite trees reaching
heights of from eight to 10 feet. Prickly-pear cactus (_Opuntia
lindheimeri_) was common in those stands of mesquite, and we saw an
occasional yucca tree. A fairly dense ground cover was formed by
blanket-flower (_Gaillardia pulchella_), marsh-elder (_Iva_ sp.),
_Flaveria oppositifolia_, _Enstoma exaltatum_, and _Croton capitatus_
var. _albinoides_.
A more open, xeric expression of the mesquite-cactus vegetation occurs
on exposed, low clay dunes (see description by Price, 1933) located on
alkaline flats bordering the laguna. At the time of our visit, most of
the mesquites in these stands were dead or dying, the cactus was
abundant, and the ground cover, which was sparse, included drop-seed
(_Sporobolus virginicus_), ragweed (_Ambrosia psilostachya_), and
_Commicarpus scandens_.
On alkaline flats flooded by hypersaline waters of the laguna following
heavy rains, _Batis maritima_ is found in the lower areas, but on the
slightly elevated areas there is low and almost continuous cover of
_Monanthochloe littoralis_, in which can be found _Batis_, _Borrichia
fructescens_, _Salicornia_ sp., _Iva_ sp., and sea-lavender (_Limonium
carolinianum_).
Near Third Pass, sea oats (_Uniola paniculata_), evening primrose
(_Oenothera_ sp.), and cordgrass (_Spartina_ sp.) are present on the
dunes, and on alkaline flats we collected _Conocarpus erectus_,
_Leucaena_ sp., and _Cassia fasciculata_ var. _ferrisiae_.
Itinerary
We reached Washington Beach from Matamoros on July 6, and drove to a
point approximately 33 miles south on the beach, where we made Camp 1
on the east side of large dunes 400 yards from the surf. From this camp
we worked the beach and dunes and also visited alkaline flats adjacent
to the Laguna Madre. On the afternoon of July 8, we drove south along
the beach and established Camp 2 on the south side of the Third Pass,
approximately 73 miles south of Washington Beach. We had intended to go
farther south but were unable to cross the Fourth Pass, an inlet three
miles south of the Third Pass. We left the barrier island on the
afternoon of July 10, after driving north from Camp 2 to the mouth of
the Rio Grande, 11 miles north of Washington Beach.
Mexican fishermen camped at the Fourth Pass told us that, had we been
able to cross the Fourth Pass, it would have been possible to drive
south on the beach all the way to La Pesca, a fishing village near the
mouth of the Rio Soto la Marina, approximately 150 miles south of
Washington Beach.
Summary of Previous Work in the Area
The ornithologist H. E. Dresser (1865-1866) worked in southern Texas
and at Matamoros, Tamaulipas, in 1863, and on one occasion reached the
mouth of the Rio Grande ("Boca Grande"). He did not visit the barrier
island or the Laguna Madre de Tamaulipas.
In their extensive travels through Mexico, E. W. Nelson and E. A.
Goldman made collections at three localities in the coastal region of
Tamaulipas but did not reach the barrier island (Goldman, 1951).
Goldman collected at Altamira, near Tampico, from April 2 to 24, 1898,
and from May 15 to 20 of the same year both he and Nelson made
headquarters at Altamira. Nelson and Goldman also collected in the
vicinity of Soto la Marina, 25 miles from the coast, from March 1 to
10, 1902, and, from February 13 to 15, they visited Bagdad, described
by Goldman (1951:260) as "a village at very low elevation on the Rio
Grande about 6 miles above the mouth of the river."
In March, 1950, C. von Wedel and E. R. Hall collected four species of
mammals and one bird on the barrier island at Boca Jesus Maria (Eighth
Pass). A report of this work published by Hall (1951) contains
descriptions of three new subspecies of mammals from the island.
A few records of birds from the southern end of the barrier island and
from other parts of coastal Tamaulipas were reported by Robins, Martin,
and Heed (1951). In 1953, R. R. Graber and J. W. Graber made
ornithological studies in the vicinity of Tampico and also reached the
western edge of the Laguna Madre de Tamaulipas. Several papers on this
work have appeared (Graber and Graber, 1954_a_, 1954_b_; Graber, 1955),
but a comprehensive account of their observations and specimens was not
published. Finally, J. R. Alcorn collected some sandpipers 20 miles
southeast of Matamoros, on August 21, 1954, obtaining the first record
of the Semipalmated Sandpiper (_Ereunetes pusillus_) in Tamaulipas
(Thompson, 1958).
Accounts of Species
Catalogue numbers in the following accounts are those of the Museum of
Natural History, The University of Kansas.
_Reptiles_
=_Gopherus berlandieri_= Agassiz: Texas Tortoise.--A pelvic girdle and
complete shell with a few attached scutes (63494) were found in
stabilized dunes at Camp 1 on July 7, and tracks were seen in the same
area. Fragments of two other shells (63493, 63495) were found on sand
flats between active dunes at Camp 1.
=_Holbrookia propinqua propinqua_= Baird and Girard: Keeled Earless
Lizard.--This lizard was abundant on dunes and in pebble-strewn
blow-out areas between dunes at Camp 2, but it occurred in smaller
numbers in the less stabilized dunes of sparser vegetation at Camp 1.
Breeding was in progress at both localities, as evidenced by the
presence of eggs in the oviducts of several females, by the heightened
coloration of both sexes, and by mating behavior.
The mating behavior of this species has not been described in the
literature, and the following observations, made by Raun at Camp 2 on
July 8, may be of interest. A male was seen to circle a female as the
latter remained motionless with tail curved upward and to the side,
exposing a patch of bright pink-orange color on the ventral surface of
the tail. At times the male approached the female from the rear and
slightly to the side, biting the dorsal part of her neck and
simultaneously attempting to effect intromission. The female several
times reacted to this approach by running forward a few steps, thereby
freeing her neck from the grasp of the male. When the male did not
attempt to approach again, the female appeared to invite copulation by
moving in front of him with tail elevated and the colored ventral
surface prominently displayed. At the time of copulation, the male
mounted from the rear on the right side of the female, grasped her
neck, and circled his tail beneath her tail; at the same time the
hindquarters of the female were arched upward.
To confirm the presumed sexes of the two individuals under observation,
both were collected while in copulation. Examination of the
still-coupled specimens showed that both hemipenes of the male were
everted and the left one had been inserted.
Apparently the pink-orange subcaudal patch of females is present only
in the mating season. It was not present on specimens of this species
taken by Raun and Wilks on Padre Island, Texas, in autumn, and it is
not mentioned in taxonomic descriptions by Axtell (1954) and Smith
(1946).
Measurements of adult specimens in our series indicate that females are
of smaller average size than males, and, as previously noted by Smith
(1946:132), females of this species have disproportionately shorter
tails than do males (Table 1).
_Holbrookia propinqua_ was previously collected on the barrier island
by Axtell (1954:31; see also Axtell and Wasserman, 1953:2), who took
specimens at Boca Jesus Maria, at a locality six to seven miles south
of Boca Jesus Maria, and at a point 20 miles east-southeast of
Matamoros. Axtell (_loc. cit._) also lists specimens in the Museum of
Zoology, University of Michigan, from Tepehuaje and from one mile north
of Miramar Beach (Tampico).
Specimens (56): 3 [M] [M] adult, 1 [M] subadult, 63433-436, Camp 1,
July 7. 33 [M] [M] adult, 63437-440, 63443-445, 63447, 63448,
63450-456, 63458, 63460, 63462, 63463, 63465-468, 63470-478; 13 [F]
[F] adult, 63441, 63446, 63449, 63457, 63459, 63469, 63479-485; 6 juv.,
63442, 63461, 63464, 63486-488; Camp 2, July 9-July 10.
TABLE 1.--MEASUREMENTS IN MILLIMETERS OF ADULT SPECIMENS OF _Holbrookia
propinqua_ FROM THE BARRIER ISLAND OF TAMAULIPAS
=======+===========+=============+==========+===============
| Number | | | Ratio:
SEX | of | Snout-vent | Tail | snout-vent
| specimens | length | length | to tail
-------+-----------+-------------+----------+---------------
Male | 33 | 56.0+-0.5[A] | 77.0+-0.7 | 0.731+-0.001
| | (49-62) | (69-85) | (0.682-0.817)
-------+-----------+-------------+----------+---------------
Female | 14 | 50.9+-0.5 | 62.2+-0.9 | 0.825+-0.001
| | (47-53) | (57-68) | (0.735-0.877)
-------+-----------+-------------+----------+---------------
[Footnote A: Mean +- standard error; range indicated in parentheses.]
=_Cnemidophorus gularis_= Baird and Girard: Whip-tailed Lizard.--At
both camps we found this species in the same general habitat in which
_Holbrookia_ occurred, but in numbers decidedly fewer than the latter.
Specimens (4): 2 [F] [F] adult, 63489, 63490, Camp 1, July 7. 1 [M]
adult, 63491, 1 [F] adult, 63492, Camp 2, July 9.
We failed to take specimens of snakes on the barrier island, but tracks
of snakes were noted on two occasions in dunes near Camp 1; one trail
led into a burrow of a kangaroo rat.
_Birds_
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 recording the number of primaries of the
old plumage that have not been dropped. For example, the designation "4
P old" signifies that all primaries except the distal four have been
molted.
Table 2 presents results of a strip census of birds along the strand,
made by three of us from the moving truck on the morning of July 10.
Birds characteristically found on sand near the surf were thus
conveniently counted in accurate fashion. Birds not ordinarily found on
the strand could not be treated this way; most were considerably less
abundant than the eight most numerous species listed in Table 2.
Over-all, the numbers of individuals listed are a good index of
abundance of the Great Blue Heron and of the common charadriiform birds
on the beach in early July. The Black Tern is an exception, however,
and this is discussed in the account of that species on page 327.
TABLE 2.--BIRDS[A] RECORDED ALONG 17 MILES OF BEACH[B] ON THE BARRIER
ISLAND OF TAMAULIPAS
=====================+=============+================
Species | Number | Birds per mile
---------------------+-------------+----------------
Great Blue Heron | 9 | 0.5
Oyster-catcher | 1 | 0.1
Black-bellied Plover | 20 | 1.2
Wilson Plover | 53 | 3.1
Willet | 43 | 2.5
Sanderling | 55 | 3.2
Laughing Gull | 136 | 8.0
Black Tern | 19 | 1.1
Caspian Tern | 82 | 4.8
Least Tern | 221 | 13.0
Royal Tern | 301 | 17.7
Cabot Tern | 122 | 7.2
+-------------+----------------
| Total: 1062 | Total: 62.4
---------------------+-------------+----------------
[Footnote A: Common Tern, Forster Tern, and Long-billed Curlew also
seen but not counted.]
[Footnote B: Between 56 and 73 miles south of Washington Beach, 11:00
to 11:45 a. m., July 10, 1961.]
=_Pelecanus erythrorhynchus_= Gmelin: American White Pelican.--A flock
of approximately 300 individuals was seen resting at the edge of the
Laguna Madre near Camp 2 on July 9. When disturbed by gunshots, the
birds circled high over the laguna and flew to the west. Among bones
found on sand flats at Camp 1 are a left tarsometatarsus and a pedal
phalanx of an American White Pelican.
Supposedly the only breeding colony of this species on the northern
Gulf coast is one in the Laguna Madre near Corpus Christi (Peterson,
1960:8), but the possibility of one or more such colonies existing in
northeastern Tamaulipas has been suggested by Amadon and Eckelberry
(1955:68) on the basis of their observations of individuals seen
soaring near the coast 15 to 20 miles south of Brownsville on April 15
and June 5, 1952. According to Hildebrand (1958:153, and personal
communication, August 14, 1961), small colonies of white pelicans do
breed in some years on two small islands, in the Laguna Madre of
Tamaulipas, located at 25 deg. 26' North and 93 deg. 30' West.
In Veracruz the species is recorded as a winter visitant and transient
(Loetscher, 1952:22; Amadon and Eckelberry, 1955:68). Coffey (1960:289)
reports the following observations for Veracruz and Tamaulipas: a flock
of 52 between Tlacotalpan and Alvarado, May 29, 1951; 80 near
Cacaliloa, April 20, 1958; 180 birds north of Alvarado, April 24, 1958;
four at Altamira, May 28, 1955; flocks of three, 13, and 37 "south" of
Matamoros, May 20, 1951; 72 at Lomas del Real, November 20, 1956.
=_Pelecanus occidentalis_= Gmelin: Brown Pelican.--Three individuals
flew north over the surf near Camp 1 on July 7, and a lone bird was
seen diving into the Gulf a short distance beyond the surf near Camp 2
on July 9. Birds seen by us probably were of the population named _P.
o. carolinensis_, which is resident along the Gulf coast (Mexican
Check-list, 1950:21).
=_Phalacrocorax_= sp.: Cormorant.--From 80 to 100 adult and juvenal
cormorants were on the laguna at Camp 2 on July 8 and 9. Probably they
were Common Cormorants (_P. olivaceus_), but, because specimens were
not taken, we cannot eliminate the possibility that some (or all) were
Double-crested Cormorants (_P. auritus_). The former breeds in coastal
lowlands of eastern Mexico, whereas the latter is known in eastern
Mexico only as a winter visitant and has not been recorded in
Tamaulipas (Mexican Check-list, 1950:24).
=_Fregata magnificens_= Mathews: Magnificent Man-o'-war Bird.--An
observation of a lone bird circling high over the laguna at Camp 2 on
July 9 seemingly constitutes the third record of this species in
Tamaulipas. Previous records were reported by Robins, Martin, and Heed
(1951:336), who found "large numbers" in the Barra Trinidad region (8
miles north of Moron) on April 27 to 29, 1949, and mentioned an
immature male taken at Tampico on April 23, 1923; this specimen has
been identified by P. Brodkorb as _F. m. rothschildi_.
=_Ardea herodias_= Linnaeus: Great Blue Heron.--Our records of this
heron are limited to the following observations: four individuals on
the beach and seven in the laguna at Camp 1, July 7; one on the beach
52 miles south of Washington Beach, July 8; one 74 miles south of
Washington Beach, July 8; two at Third Pass, July 8; 41 standing on
mud-flats at the edge of the laguna near Camp 2, July 9; nine on the
beach 56 to 73 miles south of Washington Beach, July 10; one on the
beach 42 miles south of Washington Beach, July 10.
The status of the Great Blue Heron in coastal Tamaulipas remains to be
determined. The subspecies _A. h. wardi_ (considered a synonym of _A.
h. occidentalis_ by Hellmayr and Conover, 1948) is resident and breeds
on the Gulf coast of Texas and is to be expected as a resident in
Tamaulipas (Mexican Check-list, 1950:27). The species may breed south
to Veracruz, where Loetscher (1955:22) reports it is "regular at nearly
all seasons, chiefly on the coastal plain"; he records an observation
near Tamos on July 1. The subspecies _A. h. herodias_ and _A. h.
treganzai_ winter through much of Mexico and have been recorded in
Tamaulipas (Mexican Check-list, 1950:27).
=_Florida caerulea_= (Linnaeus): Little Blue Heron.--We saw a white
(immature) individual feeding with Reddish Egrets along an inlet at
Camp 2 on July 8.
=_Dichromanassa rufescens rufescens_= (Gmelin): Reddish Egret.--This
egret was recorded only about the inlet at Camp 2, where 15 individuals
were feeding, either singly or in small groups, on July 8 and 9. We
noted frequent use of the "Open Wing" method of foraging, as described
by Meyerriecks (1960:108).
Specimen: [F] juv., 38899, ovary inactive, 587 gm., Camp 2, July 8.
This specimen is referable to the nominate subspecies, which is
resident along the Gulf coast. Our record seems to be the first for the
species in Tamaulipas.
=_Leucophoyx thula_= (Molina): Snowy Egret.--Ten individuals of this
species were feeding in association with Reddish Egrets in the inlet at
Camp 2 on July 9.
=_Hydranassa tricolor_= (P. L. S. Mueller): Tricolored Heron.--An
observation of one individual flying along the margin of the laguna
near Camp 2 is our only record of this species.
=_Nycticorax nycticorax_= (Linnaeus): Black-crowned Night Heron.--This
heron was found only at the edge of the laguna near Camp 2; ten
individuals were noted on July 8, and 20 were seen perched in a clump
of mesquite trees on July 9. Perhaps half the birds seen were in
juvenal plumage. A juvenile was shot and examined on July 9 but was not
preserved as a specimen.
There appears to be no definite evidence of breeding by this species in
Tamaulipas (Mexican Check-list, 1950:32), but such may be expected
because the species breeds locally in Texas (Peterson, 1960:19) and in
Veracruz.
=_Ajaia ajaja_= (Linnaeus): Roseate Spoonbill.--On July 9 at Camp 2,
38 spoonbills flew up from the edge of the laguna where they had been
resting near a large flock of white pelicans.
=_Cathartes aura_= (Linnaeus): Turkey Vulture.--One Turkey Vulture was
seen flying east at a point 2 miles west of Washington Beach on July
10. It is noteworthy that we saw no Yellow-headed Vultures (_C.
burrovianus_), a species recently recorded in the region of Tampico
north to Lomas del Real (Graber and Graber, 1954_a_).
=_Colinus virginianus texanus_= (Lawrence): Bob-white.--This species
was seen only in or near clumps of mesquite near Camp 1, where three
covies (7, 13, and 18 individuals) were flushed on July 7. Specimen:
[M] juv., 38900, testis 3 mm., 100 gm., 6 P old, Camp 1, July 7.
=_Porzana carolina_= (Linnaeus): Sora Rail.--On sand flats at Camp 1 we
found a left humerus and several other post-cranial skeletal elements
that have been identified by Dr. Pierce Brodkorb as belonging to this
species. All the bones are of Recent age. We have no other record of
the Sora Rail on the barrier island, but in all probability it occurs
as a migrant and winter visitant along margins of the laguna.
=_Haematopus ostralegus_= Linnaeus: Oyster-catcher.--One individual was
seen at Camp 2 on July 8, three were noted at the same locality on July
9, and one was present on the beach 72 miles south of Washington Beach
on July 10. The only previous records of this species in Tamaulipas are
a specimen ([M], 29348) taken by E. R. Hall 10 miles west and 88 miles
south of Matamoros on March 20, 1950 (herewith reported for the first
time), and three seen on the beach near Tepehuaje on May 9, 1949
(Robins, Martin, and Heed, 1951).
=_Squatarola squatarola_= (Linnaeus): Black-bellied Plover.--Plovers of
this species were uncommon but regular on the beach; frequently two
individuals were seen together, sometimes in association with one or
more Willets. Specimens (4): [M], 38915, testis 4 mm., 231 gm.; [M],
38914, testis 4 mm., 221 gm.; [M], 38916, testis 3 mm., 209 gm., Camp
1, July 7. Male, 38917, testis 4 mm., 186 gm., Camp 2, July 9. The
specimens were molting (3-4 P old) into winter plumage and showed
little or no subcutaneous fat.
Our specimens and records probably pertain to nonbreeding individuals
summering on the coast, as the species is known to do in Texas (Hagar
and Packard, 1952:9) and elsewhere in its range (Eisenmann, 1951:182;
Haverschmidt, 1955:336; A.O.U. Check-list, 1957:174). In any event,
our dates (July 6 to 10) are unusually early for autumnal migrants;
they do not reach Texas until August (Peterson, 1960:94), and Loetscher
(1955:26) gives August 7 as the earliest date for southbound migrants
in Veracruz.
=_Charadrius hiaticula semipalmatus_= Bonaparte: Ringed Plover.--We
have a single record, an adult male (38913, testis 2 x 1 mm., heavy
fat, 47.0 gm., 4 P old) taken on a sandbar at Camp 2 on July 9. The
bird was feeding in company with a flock of Sanderlings.
There is no previous record of the Ringed Plover in Tamaulipas. In
Texas, Hagar and Packard (1952:8) indicate that the first autumnal
migrants reach the central Gulf coast in the last week of July. In
coastal Mexico, the species has previously been recorded from August 23
to May 12 (Mexican Check-list, 1950:91). Therefore, the present record
must represent an exceptionally early southbound migrant, or, more
probably, a nonbreeding, summering individual. According to the A.O.U.
Check-list (1957:166), nonbreeding birds are found in summer in coastal
areas south to California, Panama, and Florida. Many individuals spend
the northern summer along the coast of Surinam (Haverschmidt,
1955:336).
=_Charadrius wilsonia wilsonia_= Ord: Wilson Plover.--This small plover
breeds commonly on the beach and on alkaline flats adjacent to the
laguna. Previous evidence of breeding in Tamaulipas consisted only of a
report of a male with brood patches and an enlarged testis taken near
Tamos on May 30, 1947 (Loetscher, 1955:26).
We saw many pairs of adults and a large number of well-grown juveniles,
and, at a point 4 miles south of Washington Beach, we collected a brood
of three small juveniles that had only recently hatched. The breeding
season apparently was drawing to a close, for several adults in our
collection were in postnuptial molt and showed marked gonadal
regression. From July 6 to 9, a few small groups of birds were noted,
but large groups were not seen until July 10, when several flocks of up
to 60 individuals were found along the coast 3 to 7 miles south of
Washington Beach.
Specimens (12): [M], 38904, testis 4.5 x 2 mm., 58 gm., 3 P old, brood
patches refeathering; [M], 38905, testis 5 x 2 mm., 59 gm., 4 P old,
brood patches refeathering; [M] juv., 38903, 6.2 gm.; 2 sex?, 38901,
38902, 5.7 and 6.2 gm., 4 miles south of Washington Beach, July 6.
Male, 38907, testis 5 x 2 mm., 56 gm., 7 P old, brood patches
refeathering; [F], 38906, ova to 1 mm., 61 gm., 3 P old, brood patches
refeathering; [F] juv., 38908, ovary inactive, 54 gm., in body molt;
Camp 1, July 6. Male, 38910, testis 6 x 3 mm., 60 gm., 4 P old; [F],
38909, ova to 1 mm., 57 gm., 4 P old, brood patches refeathering; Camp
1, July 8. Male, 38911, testis 2 x 1 mm., 55 gm.; juv., 38912, no
weight or sex recorded; Camp 2, July 9.
=_Numenius americanus parvus_= Bishop: Long-billed Curlew.--Lone
individuals and groups of two to five were noted occasionally along the
beach each day. In total, some 30 to 50 birds were counted, but some
individuals may have been recorded more than once on different days.
Specimens (2): [M], 38918, testis 4 mm., some fat, 459 gm., Camp 2,
July 9; [F], 38933, ova to 1 mm., no weight recorded, Camp 2, July 8.
Our assumption that some or all individuals seen by us were
nonbreeding, summering birds is supported by the fact that our
specimens are referable to the small, northwestern subspecies, _N. a.
parvus_, rather than to _N. a. americanus_; the latter breeds south in
the eastern United States to south-central Texas (A.O.U. Check-list,
1957:181). Loetscher (1955:27) saw a flock of 39 curlews near Tamos on
June 30, and he notes that nonbreeding birds are fairly common at all
seasons in Veracruz. Similarly, the species is present throughout the
year on the central Gulf coast of Texas (Hagar and Packard, 1952:8).
Authors of the Mexican Check-list (1950:94) do not mention the
possibility that birds of this species recorded in Mexico in July are
summering rather than migrating. Twelve supposed migrants seen along
Laguna Chila (Cacalilao), Veracruz, by Coffey (1960:291) on May 31,
1957, may have been summering birds.
=_Limosa fedoa_= (Linnaeus): Marbled Godwit.--Three were seen in
shallow waters of the laguna at Camp 2 on July 9. Specimen: [M], 38919,
testis 6 x 2 mm., fat, 305 gm., 6 P old, Camp 2, July 9. Probably our
records were of nonbreeding birds, which are known to occur in summer
elsewhere in Mexico (Mexican Check-list, 1950:94), sparingly in Texas
(Hagar and Packard, 1952:8), and in South Carolina (A.O.U. Check-list,
1957:205). Apparently the only record for this species in Veracruz is
one seen on May 11, 1954, east of Cacalilao (Coffey, 1960:292).
=_Tringa melanoleuca_= (Gmelin): Greater Yellowlegs.--Three birds were
seen on alkaline flats at Camp 1 on July 7, and two were noted at Camp
2 on July 9. There is one previous report of this species in
Tamaulipas, and, since it has been recorded as a migrant and winter
resident in Mexico between July 26 and April 26 (Mexican Check-list,
1950:95), our records seem to pertain to unusually early autumnal
migrants or, possibly, to nonbreeding, summering birds. Other
mid-summer records are available from Tamos on June 30 and July 1, and
the species is "to be expected every month of the year" in Veracruz
(Loetscher, 1955:27). Sight records for Veracruz in May (Coffey,
1960:291) may well pertain to summering birds. There are
northern-summer records for this species from Texas (Hagar and Packard,
1952:8), Surinam (Haverschmidt, 1955:367), and other areas within the
winter range of this yellowlegs (A.O.U. Check-list, 1957:190).
=_Catoptrophorus semipalmatus semipalmatus_= Gmelin: Willet.--The
Willet was common on the island. We found evidence of breeding and also
saw large flocks of birds that were either nonbreeders summering in the
area or early, postbreeding migrants from more northerly places. All
along the beach and at the edge of the laguna at both camps we found
Willets in twos or threes, often accompanied by one or two
Black-bellied Plovers. On July 10 a small juvenile was captured; two
adults in breeding plumage evidenced obvious concern at this action. On
July 6 a flock of 30 birds flew east over Camp 1, and a flock of 90 was
seen flying south over Camp 1 on July 7.
Specimens (7): [M], 38922, testis 6 x 1 mm., 264 gm., breeding plumage;
[F], 38923, ova to 2 mm., 269 gm., breeding plumage; [F], 38924, ova to
1 mm., 280 gm., 3 P old; [F], 38925, ova to 1 mm., 319 gm.; [M], 38921,
testis 7 x 2 mm., 211 gm., breeding plumage; Camp 1, July 7. Male,
38927, fat light, 231 gm., 4 P old, Camp 2, July 9. Juvenile, sex not
recorded, 38920, 43.0 gm., 1 mile south of Washington Beach, July 10.
Two of our specimens, both males, are in worn breeding plumage and
evidence no molt; another specimen, a female, is also in breeding
plumage but is molting on the breast. The remaining two adult skins in
our series are three-quarters through the molt and are for the most
part in fresh winter feather.
Dresser (1866:37) took an unspecified number of specimens of the Willet
at the "Boca Grande" in July and August, but actual breeding in
Tamaulipas was first established by C. R. Robins, who found a
"scattered colony of breeding Willets" and took a female with an egg in
the oviduct on May 9, 1949, near Tepehuaje (Sutton, 1950:135). Sutton
(_op. cit._) has discussed the characters of this specimen and of birds
from Cameron County, Texas. The specimen from Tepehuaje reportedly is
closer to _C. s. inornatus_ than to _C. s. semipalmatus_ both in size
and color, and birds from Cameron County are intermediate between the
two subspecies in size but like _C. s. inornatus_ in color.
TABLE 3.--MEASUREMENTS IN MILLIMETERS OF SPECIMENS OF CATOPTROPHORUS
SEMIPALMATUS FROM THE BARRIER ISLAND OF TAMAULIPAS
=============+======+======+========+========+========
SEX AND | | | | | Weight
CATALOGUE | Wing | Tail | Full | Tarsus | in
NUMBER | | | culmen | | grams
-------------+------+------+--------+--------+--------
[M] 38921[A] | 197 | 80.6 | 61.0 | 59.0 | 211
[M] 38922[A] | 198 | 74.4 | 61.9 | 57.9 | 264
[M] 38927 | 194 | 75.5 | 60.4 | 56.4 | 231
[F] 38923[A] | 201 | 71.0 | 59.0 | 55.4 | 269
[F] 38924 | 199 | 71.0 | 61.3 | 59.0 | 280
-----------+------+------+--------+--------+--------
[Footnote A: Specimens in worn breeding plumage.]
Measurements of our five adults from the barrier island are presented
in Table 3 for comparison with those of _C. s. semipalmatus_ and _C. s.
inornatus_ given by Ridgway (1919:316-319). Like the specimens from
Cameron County examined by Sutton (_op. cit._), our birds are
intermediate in size between average-sized individuals of the two named
subspecies. In color and pattern, we find that our specimens in
breeding plumage fall within the range of variation of _C. s.
semipalmatus_ as exemplified by five specimens in nearly identical
states of wear and fading in the Museum of Natural History.
On the basis of the evidence presently available, we are reluctant to
follow Sutton (1950:136) in assigning breeding birds from the Gulf
coastal region to _C. s. inornatus_, a name otherwise applied to a
population of birds breeding inland, in northwestern North America
south to central Utah and Colorado and east to South Dakota (and
formerly to western and southeastern Minnesota and Iowa; see A.O.U.
Check-list, 1957:190). The intermediate characters of birds breeding in
coastal Texas and Tamaulipas probably represent not the results of
actual genetic intermixing of the two named populations but, rather, an
adaptive response of the eastern coastal stock (_C. s. semipalmatus_)
to environmental modalities distinct from those operating elsewhere
within the range of the eastern coastal population or on the inland
population. Accordingly, we tentatively use the name _C. s.
semipalmatus_ for our Tamaulipan specimens, realizing that the patterns
of geographic variation in the species do not lend themselves well to
taxonomic treatment by the trinomial nomenclatural system. The need
for a comprehensive analysis of geographic variation in this species,
based, if possible, on proper segregation of age classes along the
lines followed by Pitelka (1950) for _Limnodromus_, is obviously
indicated.
PLATE 5
[Illustration: Map of coastal Tamaulipas, showing the barrier island
and localities mentioned in text. Stippled areas are extensively
marshy.]
PLATE 6
[Illustration: FIG. 1.--_Croton_ and _Fimbristylis_ on stabilized
dunes; the Laguna Madre and surrounding alkaline flats and clay dunes
are visible in the background. Habitat of Road-runner, Ord kangaroo
rat, and keeled lizard.]
[Illustration: FIG. 2.--Active dune near Camp 1. Other active dunes can
be seen in the background, in the right foreground is a clump of
_Croton_, and in the left foreground is a small clump of
_Fimbristylis_. Habitat of Road-runner, Ord kangaroo rat, and keeled
lizard.]
=_Arenaria interpres morinella_= (Linnaeus): Turnstone.--Approximately
40 individuals were noted along the beach from July 6 to 10, mostly in
small groups; the largest flock included 15 individuals. Specimens (5):
[M], 38931, testis 4 x 1 mm., moderately fat, 107 gm., 4 P old; [M],
38932, testis 3 x 1 mm., moderately fat, 103 gm., molting; 75 miles
south of Washington Beach, July 8. Male, 38928, testis 2 mm., 111 gm.,
3 P old; [M], 38929, testis 3 mm., moderately fat, 106 gm., 6 P old;
[M], 38930, testis 2.5 mm., moderately fat, 108 gm., 6 P old; Camp 2,
July 9.
The only previous record of the Turnstone in Tamaulipas is an
observation of an unspecified number at Tepehuaje on May 9, 1949
(Robins, Martin, and Heed, 1951). The dates of our records suggest that
nonbreeding birds summer along the coast of Tamaulipas. The species is
present in small numbers in summer along the central Gulf coast of
Texas (Hagar and Packard, 1952:8). Loetscher (1955:26-27) does not
report records for Veracruz in summer, but records of the species in
Yucatan on May 31, 1952 (Paynter, 1955:101), and on June 16, 1900
(Mexican Check-list, 1950:79), probably represent summering
nonbreeders. Probably also in the same class are supposed "migrants"
seen at Coatzacoalcos on May 17, 1954, and June 4, 1955 (Coffey,
1960:290).
Inasmuch as Haverschmidt (1955:368) reports that nonbreeding birds
summering in Surinam only occasionally assume breeding plumage, it is
noteworthy that our specimens were molting from nuptial (summer) to
winter plumage. None of the nonbreeding northern shorebirds observed by
Eisenmann (1951:183) in Panama in summer were in nuptial plumage.
=_Crocethia alba_= (Pallas): Sanderling.--This sandpiper was noted each
day along the beach, occasionally singly but more frequently in groups
ranging from 10 to 50 individuals. Specimens (7): [M], 38936, testis 2
mm., light fat, 49 gm., 5 P old, Camp 1, July 7. Female, 38937, ova to
1 mm., fat, 58 gm., 4 P old; [M], 38939, fat, no weight recorded, 6 P
old, breeding plumage; 3 [M] [M], 38940-38942, fat, no weight recorded,
4-5 P old; Camp 2, July 9.
With one exception as noted, our specimens are in worn, nonbreeding
plumage and are replacing their old feathers with new ones
fundamentally the same in color and pattern; the exceptional specimen
is molting from worn breeding plumage into nonbreeding plumage. Only
one other individual in breeding feather was seen on the island.
According to the Mexican Check-list (1950:99), the Sanderling has been
recorded in Mexico from August to May 19. In Texas, Peterson (1960:107)
reports that it is a migrant, April to June and July to November, and
that it winters along the coast. We suspect that many of the birds
present in Texas in June and July, together with those recorded by us
in Tamaulipas in July, are nonbreeding, summering individuals.
Haverschmidt (1955:368) reports northern-summer records from Surinam,
and, according to the A.O.U. Check-list (1957:208), nonbreeding birds
occur in summer extensively through winter range of the species,
including the Gulf coast of the United States.
=_Micropalama himantopus_= (Bonaparte): Stilt Sandpiper.--Two birds in
worn winter plumage were taken as they foraged together at the edge of
the laguna near Camp 2 on July 9. Specimens (2): [M], 38934, testis 2.5
mm., heavy fat, 116 gm., 4 P old; [M], 38935, testis 3 mm., fat, 111
gm., 4 P old.
Our specimens probably were nonbreeding birds summering between the
breeding range in arctic America and the winter range in northern South
America. The A.O.U. Check-list (1957:202) does not mention nonbreeding,
summering records of this species. The 251 birds seen by Coffey
(1960:292) at Cacalilao, Veracruz, on May 11, 1954, were probably
migrants.
=_Recurvirostra americana_= Gmelin: American Avocet.--This species was
seen only in three large flocks flying south along the beach, as
follows: 56 birds 72 miles south of Washington Beach, July 8; 38 birds
73 miles south of Washington Beach, July 8; 29 birds 72 miles south of
Washington Beach, July 10. All birds were in winter plumage.
All these birds were possibly autumnal migrants, but the dates are
early; the species has not previously been recorded on migration in
Mexico before August (Mexican Check-list, 1950:101). The species is
known to breed in San Luis Potosi (Mexican Check-list, _loc. cit._) and
along the lower coast of Texas ("rarely to Brownsville"; A.O.U.
Check-list, 1957:209); avocets thus may also breed in coastal
Tamaulipas.
=_Larus argentatus_= Pontoppidan: Herring Gull.--A first-year bird was
observed near Camp 2 on July 8, and two subadult individuals were seen
on the beach between the Third and Fourth passes on July 8.
=_Larus atricilla_= Linnaeus: Laughing Gull.--This gull was common all
along the beach. Many individuals were in full breeding feather and
many subadult birds were also present. Specimens (6): [M] subadult,
38944, testis 5 x 1 mm., 325 gm., molting; [F], 38945, ovary small, 309
gm., in molt, brood patches refeathering; sex?, 38943, 315 gm., in
molt; sex? subadult, 38946, 327 gm., in molt; Camp 1, July 7. Female
subadult (second-year), 38947, 305 gm., in molt, Camp 2, July 8.
Female, 38926, ova to 2.5 mm., 313 gm., 8 P old, Camp 2, July 10.
The Mexican Check-list (1950:105) refers to the Laughing Gull as a
common winter resident on both coasts of Mexico from August 7 to May
17, but Loetscher (1955:29) found it locally common throughout the year
on the coast of Veracruz, and he mentioned seeing birds a short
distance south of Tampico in June and July. The status of this gull in
Tamaulipas remains to be determined; probably it will be found breeding
locally, but many of the birds summering in eastern Mexico are most
likely nonbreeders (A.O.U. Check-list, 1957:226).
=_Chlidonias niger surinamensis_= (Gmelin): Black Tern.--On July 6, 7,
8, 9, and on the morning of July 10, we saw this species only
occasionally, recording in total not more than 50 individuals. But,
about noon on July 10, we observed at least 300 birds in compact flocks
of about 50 individuals each between Washington Beach and a point about
9 miles south of that locality. Approximately one in ten birds seen was
in breeding plumage, the rest being in winter or subadult plumages,
which are indistinguishable in the field. Perhaps some of the birds
seen were nonbreeding, summering individuals, but we presume that the
large groups were southbound migrants, and we note that autumnal
migrants appear in northern Veracruz as early as July 1 (Loetscher,
1955:30). On the central Gulf coast of Texas, Hagar and Packard
(1952:9) indicate that an influx of birds occurs in the last week of
July, and small numbers of birds, presumably nonbreeding individuals,
are present along the Gulf coast throughout June and July. Dresser
(1866:45) found this species to be "common at the Boca Grande during
the summer."
Specimens (2): [M], 38948, testis 6 mm., moderately fat, 68 gm., in
breeding plumage, Camp 1, July 7. Female, 38949, ovary inactive, 49
gm., molt into winter feather almost complete, Camp 2, July 10.
=_Hydroprogne caspia_= (Pallas): Caspian Tern.--The only published
record of the Caspian Tern in Tamaulipas is a report of one seen at
Lomas del Real on November 20, 1956 (Coffey, 1960:260), but we found it
moderately common all along the beach and at the margin of the laguna.
It was frequently associated with the Royal Tern, which outnumbered it
better than three to one (see Table 2). The species is resident and
breeds along the coast of Texas, and it probably has similar status in
Tamaulipas. However, in Veracruz it is known only as a winter visitant
(Loetscher, 1955:30) and as a spring migrant (Coffey, 1960:293).
Specimen: [F], 38950, ova to 2 mm., moderately fat, weight not
recorded, 5 P old, Camp 2, July 9.
=_Sterna hirundo hirundo_= Linnaeus: Common Tern.--We took a specimen
([M]?, 38951, no fat, 165 gm.), 49 miles south of Washington Beach on
July 8, and saw two others over the laguna at Camp 2 on July 9. Our
specimen had nearly finished with molt and feather growth into adult
winter plumage. The status of Common Terns in Tamaulipas is uncertain;
our record, and records from Tamos on July 1, 1952, and June 12, 1953
(Loetscher, 1955:29), probably pertain to nonbreeding, summering birds.
Yet, the species has bred on the Texas Gulf coast (A.O.U. Check-list,
1957:235), and it reasonably may be expected to nest in Tamaulipas.
Coffey (1960:293) saw two individuals at Altamira on May 10, 1954.
=_Sterna forsteri_= Nuttall: Forster Tern.--Six were recorded near Camp
1 on July 7, and two were seen on the beach on July 6 and 10. The
Mexican Check-list (1950:108) does not cite records for Tamaulipas, but
the A.O.U. Check-list (1957:234) includes northern Tamaulipas within
the breeding range. Evidence suggesting breeding of the species in
extreme northern Veracruz is reported by Loetscher (1955:29) in the
form of a female specimen with "ovary greatly enlarged" taken seven
miles west of Tampico on May 30, 1947. In the same area the species
also seems to spend the summer as a nonbreeder, for Loetscher (_loc.
cit._) saw 20, nearly all in nonbreeding plumage, on July 1, 1952.
Specimens (4): [M], 38952, testis 4.5 mm., 150 gm., 8 P old; [M],
38955, testis 2 mm., 138 gm., 2 P old; [M], 38953, testis 5 x 1 mm.,
142 gm., 5 P old; [F], 38954, ova to 1 mm., 148 gm., 2 P old; Camp 1,
July 7.
=_Sterna albifrons antillarum_= (Lesson): Least Tern.--The status of
this species in Tamaulipas is uncertain, but there is reason to
believe that it breeds, at least in small numbers. We found the species
moderately common and generally flying about in twos, possibly mated
pairs, near both camps and on the beach. Breeding is suggested by the
large sizes of the testes of the two males collected and by the
presence of brood patches on a female taken on July 6, but we have no
direct evidence of nesting in Tamaulipas, and it should be noted that
this species is known to spend the summer in nonbreeding condition at
many places (A.O.U. Check-list, 1957:239). Loetscher (1955:30) suggests
that the species may be found breeding in Veracruz and mentions a
record of 15 seen at Miramar, Tamaulipas, on June 26, 1952. Dresser
(1866:45) found it to be "abundant" at the "Boca Grande" in summer.
On July 10, we saw flocks of 15 to 20 individuals flying along the
beach a few miles south of Washington Beach.
Specimens (4): [M], 38958, testis 11 x 4 mm. (right testis 5 x 4 mm.),
light fat, 45 gm., 6 P old; [M], 38959, testis 11 x 4 mm. (right testis
7 x 4 mm.), light fat, 45 gm., 6 P old; [F], 38956, ova to 2.5 mm.,
42.5 gm., 6 P old, brood patches refeathering; Camp 1, July 6. Female,
38957, ova to 1 mm., 44 gm., Camp 1, July 7. This last specimen had
essentially completed the autumnal molt into winter plumage, with only
a few feathers remaining ensheathed basally.
Our specimens are referable to _S. a. antillarum_, being paler dorsally
and slightly lighter gray on the hind-neck than specimens of _S. a.
athalassos_ from Kansas, with which they were compared.
=_Thalasseus maximus maximus_= (Boddaert): Royal Tern.--This species
was common all along the beach, occurring for the most part in flocks
of from ten to 50 individuals in association with Cabot Terns. Data on
gonadal condition and brood patches of some of our specimens suggest
that breeding occurs in coastal Tamaulipas, as previously reported by
the Mexican Check-list (1950:110). Robins, Martin, and Heed (1951)
report seeing one Royal Tern near Tepehuaje on May 9, 1949, and Dresser
(1866:44) found the species "common at the Boca del Rio Grande during
the summer."
Specimens (6): [M], 38960, testis 9 x 4.5 mm., not fat, 484 gm., 6 P
old, brood patches refeathering, 4 miles south of Washington Beach,
July 6. Male, 38961, testis 7 x 3 mm., 455 gm., no brood patches, 8
miles south of Washington Beach, July 6. Male, 38962, testis 10 x 5
mm., 387 gm., brood patches refeathering; [F], 38963, ova to 1 mm., 358
gm., 3 P old; [F], 38964, ova to 3 mm., 389 gm., 8 P old; Camp 1, July
7. Female, 38994, ova to 2 mm., 536 gm., brood patches refeathering,
Camp 2, July 10.