Nest and Eggs of the Streamer-Tailed Tyrant (Gubernetes yetapa) from Brazil and Paraguay

Abstract

ABSTRACT The breeding biology of approximately one third of all Fluvicolinae species is largely unknown and little is known about Streamer-tailed Tyrant (Gubernetes yetapa). Despite being locally fairly common, only a brief description of its nest has been published. For the species, Chubb (1910) described gonadal state, nest building, and young seen, but no additional details have been published. Here, we describe the nest and eggs of Streamer-tailed Tyrant from Brazil and Paraguay and review nesting activity based on fledgling records from Brazil. The nest was an open cup in the center of a clump of Saccharum sp. grass within a marshy area. The outer portion was lined with thick grass stems. The inner portion of the cup was lined with fine roots, grass stems, and shed snake skins (Colubridae and Viperidae). The nest contained three totally white and oval shaped eggs. Egg mass ranged from 6.84–9.02 g. The period of nesting activity apparently lasted at least from October through January, similar to sever...