242 BIKDS OF THE REPUBLIC OF PANAMA — PART 2 



found chestnut-collared swifts nesting in caves in the months of May 

 and June. In another area, in a narrow, steep- walled canyon traversed 

 by a mountain stream, single pairs had placed their nests on the cliffs 

 on small ledges protected above by overhanging rock. Nests in caves 

 were rather flimsy, one being only 62 mm. high. Those outside were 

 more substantial, the largest being 168 mm. tall. They were built of 

 mud and moss, those in exposed locations rising cone-shaped from the 

 base. The depth of the cup was about 12 mm. The eggs were white, 

 somewhat stained from the nest materials. One shown in a photo- 

 graph (loc. cit., fig. 15) is subelliptical in form. Size range was 21.9- 

 24.2 X 15.0-15.4 mm. While 2 eggs constituted a set, it was usual to 

 find several others lying below, apparently knocked accidentally from 

 the rather shallow nests. 



The nest of the typical form C. r. rutilus in Trinidad is described 

 by Snow (Zoologica, vol. 47, 1962, p. 135) as "a substantial bracket, 

 semicircular in horizontal section, with a shallow depression for the 

 eggs. It is made of various plant fibres, usually including some moss, 

 and is fixed, presumably with saliva, onto a smooth rock-face or wall, 

 a few feet above water." Other nesting locations were in sea-caves, 

 and in culverts. Nests were repaired and used in successive years. 

 Two eggs, white in color, form the normal set. Belcher and Smooker 

 (Ibis, 1936, p. 26) report measurements in 3 sets as 22.0-22.9 X 14.0- 

 15.0 mm. 



The chestnut-collared swift has been included only under the spe- 

 cific name because of present uncertainty as to the status of the races 

 that have been described from Central America. Dr. Allan Phillips in 

 recent studies (Anal. Inst. Biol. Mexico, vol. 32, 1961 = March 30, 

 1962, pp. 333-335) in which he has examined pertinent specimens, has 

 found that in Mexico these birds appear to be present only during 

 the presumed breeding period. In Morelos and Nayarit there is no 

 record of them between early August and early May. In Giiapas they 

 have been found between February 18 and October 2 but not later. 

 Dr. Phillips recognizes a paler race, Cypseloides rutilus brunncitorqucs 

 (Lafresnaye), as nesting in the mountains of Mexico northwest of 

 the Isthmus of Tehuantepec with C. r. griseifrons described by Nelson 

 from Nayarit as a synonym. A darker population which he lists as 

 C. r. nubicola (Brodkorb) is found in Chiapas and ranges from there 

 to Bolivia. But, as stated, these seem not to be resident in Mexico. 

 It is suggested that both forms leave Mexico to winter in South 

 America. On this basis it is presumed that both would pass through 

 Panama. As this problem had not been raised when I examined the 



