FAMILY HIRUNDINIDAE 



33 



beyond El Volcan, Chiriqui, March 21, 1954, had the iris dark brown; 

 tarsus, toes, and claws fuscous. Another adult female, taken at 1900 m 

 on the west base of Volcan de Chiriqui, March 4, 1965, also had the iris 

 dark brown, tarsus and toes dark brown, claws fuscous-black. 



Measurements. — Males (10 from western Panama and Costa Rica), 

 wing 92.0-99.0 (94.3), tail 45.4-52.6 (49.0), culmen from base 6.7-8.0 

 (7.2), tarsus 9.1-10.6 (9.8) mm. 



Females (10 from western Panama and Costa Rica), wing 87.5-97.1 

 (91.5), tail 41.8-52.6 (48.0), culmen from base 6.0-7.9 (6.8), tarsus 

 9.2-10.6 (9.9) mm. 



Resident. Common over open areas in the highlands of Chiriqui 

 above 1000 m elevation, ranging to the higher levels; reported on upper 

 Rio Chiriqui (Fortuna Dam site), central Chiriqui (Ridgely) re- 

 corded on Cerro Flores, eastern Chiriqui, and also in the district of 

 Calovevora, northern Veraguas; casual at Gatun, Canal Zone. It is 

 also common at Cerro Campana, western Province of Panama, where 

 Ridgely first found it in December 1967; it was then already numerous 

 and had probably been there for some time. 



There is a specimen in the American Museum, taken by Griscom's 

 party east of the main mountain range in western Chiriqui on Cerro 

 Flores, north of Remedios. A male and 2 females in the British Mu- 

 seum, secured by Arce, are labeled Calovevora, northern Veraguas, 

 1869. 



These small swallows, common over open areas, come regularly 

 about houses and farm buildings. In several seasons I found them nest- 

 ing on ledges and under the eaves of the house that we occupied at Palo 

 Santo beyond El Volcan, Chiriqui. Hundreds also nested on rock cliffs 

 on the high mountain slopes to 2800 m on El Baru. Nests were made of 

 dried grasses and other vegetation, filling the crevices that they occu- 

 pied. Some of the structures seemed loosely built, as on several oc- 

 casions I found broken eggs that had fallen beneath the nests. 



Skutch (Auk, 1952, pp. 393-405, and Pac. Coast Avif. no. 34, 1960, 

 pp. 279-280), in detailed studies in southwestern Costa Rica, found 

 them using any available cavities, from those in rotted dead tree trunks 

 to artificial shelters under the eaves of houses, crevices in walls, or 

 occasionally tunnels dug by animals in banks of earth along trails and 

 highways. The thatched roofs on houses and other buildings in country 

 areas also furnish shelter. He reported sets of 2, 3, and 4 eggs. These 

 were glossy white, without markings. Measurements of 6 eggs were 

 16.3-16.7x11.5-12.2 mm. 



He recorded that laying begins in March, with both male and female 



