36 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



near Pedro Miguel Locks. N. G. Smith (Willis and Eisenmann, 1979, 

 Smiths. Cont. ZooL, no 291, p. 24) saw 4 at Barro Colorado Island, 

 Canal Zone, on August 20, 1972, that were probably of this race. 



STELGIDOPTERYX RUFICOLLIS (Vieillot): Rough-winged Swallow, 

 Golondrina Ala de Sierra 



Figure 3 



Hirundo ruficollis Vieillot, Nouv. Diet. Hist. Nat., nouv. ed., vol. 14, September 

 1817, p. 523. (Bresil = vicinity of Rio de Janeiro.) 



Above, grayish to blackish brown, darker on remiges and rectrices 

 than on back; throat light brown to grayish white, abdomen white to 

 yellowish white. 



Description. — Length 125-132 mm. Adult (sexes alike), above gray- 

 ish to blackish brown; throat variable in the subspecies from cinnamon- 

 buff to grayish white; breast light brown, rest of undersurface white. 

 Rump varying in subspecies from brownish to whitish. Adult male 

 (and female, to less degree) with the tips of the barbs on the outer 

 border of the first primary stiffened and recurved, so that they are 

 roughened to touch. 



These are the most common and widely distributed of the swallows 

 of Panama, ranging in open areas from the lowlands to the slopes of 

 the mountains. In forested regions they occur along streams and 

 around clearings. 



The whitish-rumped resident subspecies is seen often in pairs along 

 roads, especially where these are bordered by cut banks in which there 

 are shallow cavities that may shelter nest sites. In the period of north- 

 ern winter the 2 dark-rumped migrant races from the north range in 

 small flocks along the larger streams through the lowlands. 



The taxonomy of this complex remains in dispute, both as to the 

 number of species and subspecies to be recognized. Here all forms are 

 treated as conspecific. 



[Stiles (Auk, 1981, p. 282) has studied the systematics of these 

 swallows in Costa Rica, concluding that 2 species are represented. Be- 

 cause he cites Wetmore's unpublished manuscript for the present vol- 

 ume, we have left Wetmore's account essentially unaltered. Basically, 

 there are 2 distinct forms of Stelgidopteryx : a northern one that is uni- 

 form brown above and mostly whitish below (serripennis group), and 

 a more colorful southern one with a white rump, rufous throat, and 

 yellowish underparts (ruficollis group). Stiles maintains that the 2 

 groups behave as distinct species in Costa Rica, with serripennis being 



