6 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Description. — Length 115-125 mm. Adult (sexes alike), upper sur- 

 face of body, including side of head, and tail grayish brown; forehead 

 slightly paler than crown; back also usually somewhat paler; scapulars, 

 tertials, rump, and upper tail coverts with lightly marked paler margins; 

 wings, including coverts, darker (blacker); undersurface, including 

 sides and undertail coverts, white; a broad band of a grayish brown 

 across the foreneck and upper breast, continued laterally on the upper 

 sides. 



Immature, rump, upper tail coverts, tertials and wing coverts tipped 

 with cinnamon-buff; chest band also with paler tips. 



Measurements. — Males (10 from New Jersey, Rhode Island, Iowa, 

 Nevada, and Alaska), wing 99.7-105.7 (102.0), tail 47.0-51.7 (49.1) 

 culmen from base 8.0-8.9 (8.3), tarsus 10.0-11.1 (10.4) mm. 



Females (10 from New Jersey, District of Columbia, Louisiana, 

 Kentucky, Illinois, Idaho, and Ontario), wing 94.4-102.1 (98.0), tail 

 42.6-49.6 (47.6), culmen from base 7.0-8.7 (7.8), tarsus 9.9-11.7 

 (10.6) mm. 



Winter visitor from the north, September to April, found irregu- 

 larly, often with flocks of other swallows. The first fall migrants may 

 appear early, as Ridgely (in litt.) reported 2 at El Llano, eastern Prov- 

 ince of Panama on August 2, 1974, Arbib and Loetscher recorded 1 

 at Gatun, Canal Zone, August 26, 1934, and Eisenmann reported some 

 seen with other swallows on the savannas of Code, September 1, 1954. 

 There are numerous records through September and October, when 

 they appear still to be in southward passage. Specimens in the British 

 Museum were taken by H. J. Kelsall at sea in the Gulf of Panama on 

 October 4 and 25, 1924. Griscom recorded 3 taken October 2, 6, and 17, 

 1930, at Puerto Obaldia on the eastern San Bias coast. 



A few may be seen through the winter period, as Eisenmann recorded 

 several at Playa Coronado, November 25, 1962, and Jewel saw them 

 in the Canal Zone on November 30, 1911, and February 22, 1912. The 

 latter date may mark the beginning of the migration northward, during 

 which lesser numbers are recorded in March and April. Late dates of 

 small numbers, presumably stragglers, are reported for May 11, 15, 22, 

 27 (Ambrose, Ridgely, N. G. Smith) and June 3, 1961 (Gatun Dam, 

 Ambrose, 10 birds) . On March 14, 1944, I noted several over the Gulf 

 of Panama, in crossing from Isla San Jose to Balboa. Griscom re- 

 corded 10 on March 8, 1927, a mile offshore from Cabo Garachine. 

 Two males in the Hancock collections of the Los Angeles County Mu- 

 seum were collected April 27, 1939, from the deck of the yacht Velero 

 III in Bahia Caledonia, on the eastern San Bias coast. 



