1 6 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



along the Pan American Highway from David eastward for 30 km. 

 Cliff Swallows are found in Panama as late as May 17, when in 1973 

 Ridgely saw 50 near Escobal. 



PETROCHELIDON PYRRHONOTA PYRRHONOTA (Vieillot) 



Hirundo pyrrhonota Vieillot, Nouv. Diet. Hist. Nat., vol. 14, September 1817, 

 p. 519. (Paraguay.) 



Characters. — Forehead clear white in most individuals, size smaller; 

 wing 107-112.8 mm. 



Measurements. — Males (10 from eastern and western United States 

 and southern Canada), wing 108.4-112.8 (109.8), tail 46.6-50.9 (48.9), 

 culmen from base 8.9-10.6 (9.7), tarsus 11.3-13.2 (12.5) mm. 



Females (10 from eastern and western United States), wing 107.1- 

 109.9 (108.4), tail 44.7-49.0 (47.9), culmen from base 9.4-10.2 (9.7), 

 tarsus 12.1-12.8 (12.5) mm. 



Migrant from the north, common. 



Specimens examined are as follows: Male, in the British Museum 

 (Natural History), received in the Tweedale Collection, without date 

 of collection, purchased from the dealer G. A. Frank of London. It is 

 assumed to be from the Canal Zone, as it shows the characteristic prepa- 

 ration of McLeannan. One of his small labels attached reads "45 male." 

 The wing measures 110.5 mm. 



Immature male, USNM no. 30556, collected at sea "N. of Panama, 

 Oct. 20, 1863, Capt. J. M. Dow." The locality is uncertain, but prob- 

 ably means north of Panama City, off the west coast. The wing mea- 

 sures 108.0 mm. 



Female, no. 2378, collection of Gorgas Memorial Laboratory, from 

 Almirante, Bocas del Toro, October 10, 1960; wing 111.0 mm. 



Male adult, USNM no. 461062, Las Lajas, Chiriqui, February 26, 

 1956; wing 109.5 mm, A. Wetmore. 



Adult male, AMNH no. 500904, Panama City, April 3, 1897; wing 

 110.5, C. M. Harris. 



As the breeding range of this race extends widely through the central 

 and northern United States, this subspecies may be the one most com- 

 monly represented in the migrant flocks that come to Panama. These 

 are seen commonly through September and October, and again from 

 late February through March to early May. Apparently the majority 

 are birds of passage with the main wintering ground in South America. 



There is considerable variation in size in this nominate race, as indi- 

 cated by wing length. Those that nest in the west, from Oregon north- 



