Breeding

Long-term studies are necessary to determine core aspects of this species’ reproductive biology, but fragmentary observations give a sense of the general phenology. Nests are built in caves, rock crevices, mine tunnels, and in at least one instance, a vacant stone hut (Pearson 1953, Dorst 1962, Carpenter 1976).  Nests are constructed with often copious amounts of wool from sheep or alpaca, lichens, mosses, leaves, grass, and lined with feathers or hair (Bond and Meyer de Schauensee 1943, Pearson 1953, Dorst 1962). These bulky nests are glued to vertical rock surfaces with saliva, as in swifts. Pearson (1953) found no caves with more than one nest, and nests are often used repeatedly from year to year, with records of new nests built over old nests (Johnson 1967).

Fresh nests have been described from Chile in November, with young or well-developed eggs in January. Eggs are oblong and plain white, averaging 16.8 x 10.4mm (n = 6). Clutches have two eggs (Johnson 1967).