Breeding Success of Primary and Secondary Burrow-Nesting Birds on Stream Banks in Central Brazil

Abstract. Underground burrow nests of three bird species: Amazonian Motmot Momotus momota, Rufous-tailed Jacamar Galbula ruficauda and Swallow Tanager Tersina viridis were monitored for eight years on stream banks, in a Seasonal Semideciduous Forest, to enable determining whether, or not, being a burrow excavator bird is associated with nest predation, and how important the role played by nest dimensions in this nesting system is. Predation was the main cause of nest failures, although there was no significant difference in nest predation between secondary (SCN) and primary (PCN) cavity (burrow)-nesting species. Offspring predation rate was the only one recording significant result; the lowest offspring predation rate was associated with PCN species — Amazonian Motmot but, again, there was no significant difference between PCN and SCN species. On the other hand, SCN species — Swallow Tanager has compensated offspring losses due to its increased fecundity, which enabled two broods per breeding season. No nest parameter has influenced predation rates, although our data suggested the need of further investigating the length of the nest access tunnel.