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قراءة كتاب Vertebrates from the Barrier Island of Tamaulipas, México

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‏اللغة: English
Vertebrates from the Barrier Island of Tamaulipas, México

Vertebrates from the Barrier Island of Tamaulipas, México

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دار النشر: Project Gutenberg
الصفحة رقم: 5

38904, testis 4.5 × 2 mm., 58 gm., 3 P old, brood patches refeathering; ♂, 38905, testis 5 × 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 × 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 × 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 × 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 Tamós 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 México 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 × 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 México (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 México 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 Tamós 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 × 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 × 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
Wing Tail Full
Tarsus Weight
♂ 38921[A] 197 80.6 61.0 59.0 211
♂ 38922[A] 198 74.4 61.9 57.9 264
♂ 38927 194 75.5 60.4 56.4 231
♀ 38923[A] 201 71.0 59.0 55.4 269
♀ 38924 199 71.0 61.3 59.0 280