Part 4

=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 (, 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): , 38915, testis 4 mm., 231 gm.; , 38914, testis 4 mm., 221 gm.; , 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): , 38904, testis 4.5 x 2 mm., 58 gm., 3 P old, brood patches refeathering; , 38905, testis 5 x 2 mm., 59 gm., 4 P old, brood patches refeathering; 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; , 38906, ova to 1 mm., 61 gm., 3 P old, brood patches refeathering; 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; , 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): , 38918, testis 4 mm., some fat, 459 gm., Camp 2, July 9; , 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: , 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): , 38922, testis 6 x 1 mm., 264 gm., breeding plumage; , 38923, ova to 2 mm., 269 gm., breeding plumage; , 38924, ova to 1 mm., 280 gm., 3 P old; , 38925, ova to 1 mm., 319 gm.; , 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 -------------+------+------+--------+--------+-------- 38921 | 197 | 80.6 | 61.0 | 59.0 | 211 38922 | 198 | 74.4 | 61.9 | 57.9 | 264 38927 | 194 | 75.5 | 60.4 | 56.4 | 231 38923 | 201 | 71.0 | 59.0 | 55.4 | 269 38924 | 199 | 71.0 | 61.3 | 59.0 | 280 -----------+------+------+--------+--------+--------

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

PLATE 6

=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): , 38931, testis 4 x 1 mm., moderately fat, 107 gm., 4 P old; , 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; , 38929, testis 3 mm., moderately fat, 106 gm., 6 P old; , 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): , 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; , 38939, fat, no weight recorded, 6 P old, breeding plumage; 3 , 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): , 38934, testis 2.5 mm., heavy fat, 116 gm., 4 P old; , 38935, testis 3 mm., fat, 111 gm., 4 P old.