Part 3

=======+===========+=============+==========+=============== | Number | | | Ratio: SEX | of | Snout-vent | Tail | snout-vent | specimens | length | length | to tail -------+-----------+-------------+----------+--------------- Male | 33 | 56.0+-0.5 | 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) -------+-----------+-------------+----------+---------------

=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 adult, 63489, 63490, Camp 1, July 7. 1 adult, 63491, 1 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 RECORDED ALONG 17 MILES OF BEACH 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 ---------------------+-------------+----------------

=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: 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, 1954a).

=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: 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.