Extreme use of feathers for nest construction by the Chilean Swallow (Tachycineta leucopyga) in the sub-Antarctic forests of southern Chile

Abstract

Nesting birds commonly incorporate feathers into nest linings given their insulation properties. Although use of feathers is common among swallows, here we provide the first recording of nests built almost completely with feathers (57-60% of total nests mass), by the Chilean Swallow (Tachycineta leucopyga) in southern Chile. Low temperatures or a high availability of feathers near the nesting sites could have elicited this response in the breeding birds, but further observations are needed to determine the frequency of the extreme use of feathers in this species, and the proximate causes promoting such behavior.