Abundância, comportamento e reprodução de taperuçus (Aves: Apodidae) em três cachoeiras do Cerrado Central

Abstract

Swifts are birds of the Apodidae family, which feed on small insects captured in aerial foraging. They occur only in the Americas and are poorly studied. In this work, we analyzed three colonies of swifts in waterfalls of the Cerrado biome, two in Minas Gerais and one in Goiás. We did censuses by direct counting and captures with mist nets in the morning and afternoon periods. We recorded three species: Cypseloides senex (Great Dusky Swift), Cypseloides fumigatus (Spoot Swift) and Streptoprocne zonaris (White-collared Swift). The current absence of C. fumigatus at Queimado Waterfall worries us, as it may be related to the construction of a hydroelectric plant upstream. We observed differences in the abundance and foraging time of the swifts between the colonies. Abundance was higher at Salto do Itiquira Waterfall (5.536 ± 1.198), median at Queimado Waterfall (721 ± 223) and lower at Buritizinho Waterfall (247 ± 165). The foraging time was inverse: higher in Buritizinho (13h), median in Queimado Waterfall (12h) and lower in Salto do Itiquira (10h). This can be explained by the fact that larger flocks benefit from the information generated by individuals, allowing greater efficiency in searching for food. In June/September, we recorded copulations of C. senex perched on the vegetation of the wet walls around the waterfall and during free fall flight. Soon after, they started building the nests and, in September/October, there were already eggs. The chicks were born in October/November and left the nest by December at the latest. The nest of C. senex is thin and built near the water, smaller than that of S. zonaris, which is located in sheltered places without running water. We report fidelity of C. senex individuals with recaptures of banded individuals in the same colonies, as well as daily baths of C. senex and S. zonaris perched vertically on the waterfall. An advantage of swifts occupying waterfalls may be the regular practice of bathing, which helps to combat ectoparasites and avoid predators in flight. Conservation plans for C. senex should cover the upstream catchment of the waterfalls and establish measures to ensure the quality of stream water.