Description of the nest, eggs, and nestling growth of the endangered moustached woodcreeper Xiphocolaptes falcirostris

The moustached woodcreeper Xiphocolaptes falcirostris is a widely distributed species, with an irregular occurrence pattern in the Brazilian Caatinga biome and the eastern and northeastern extremes of the Cerrado savanna. It is the only member of the genus listed under some threat of extinction (vulnerable), both nationally and globally. Here, we present the first description of the nest, eggs, and nestling growth patterns of moustached woodcreeper. The data were collected in eastern Maranhão state (Brazil), in the municipalities of Parnarama and São João do Sóter, where we found two active nests. The first nest was built in a hole in the main trunk of a Bignoniaceae tree, at a height of approximately 7 m. When it was found, this nest contained two nestlings that still lacked feathers. The second nest was built in the upper part of the trunk of a dead carnauba palm ( Copernicia prunifera ), at a height of 1.5 m, and contained two unmarked white eggs. The growth curves of the nestlings indicated that, in terms of the majority of the parameters analyzed, the nestlings abandoned the nest before reaching full adult size. The nestlings remained in the nest for 21–22 days. The results of the study are consistent with the general pattern recorded for other species of the genus Xiphocolaptes and represent an important advance in the understanding of the reproductive biology of bird species that nest in cavities.