Ecologia reprodutiva de Phaethornis idaliae (Aves: Trochilidae) (Bourcier & Mulsant, 1856) na Serra de Sapiatiba, estado do Rio de Janeiro

Abstract

Breeding is a key point in ecology and evolution studies, thus so much effort has been expended to understand basic aspects of natural history and parental care. However, in tropical environments even basic aspects of natural history of birds are unknown, hindering a comparative approach to search for patterns. Therefore, effective conservation actions in Atlantic Rainforest depend largely on knowledge resulting from basic research about endemics and poorly known species as the Minute Hermit, Phaethornis idaliae. Here, I aimed to describe basic aspects of breeding biology of P. idaliae and evaluate the effects of environmental variables (such as time elapsed during breeding season, time of day and daily temperature) in parental care (eggs and nestlings phases, nestling age, time to fledging and feeding rate). I also investigated spatial distribution of nesting sites and identified plants used as nest support by P. idaliae. During August 2014 and February 2016 I searched for nests, which were mapped with GPS and regularly monitored to investigate nestlings development and nests spatial distribution during breeding season. I found 52 nests made mainly of kapok fiber of Ceiba sp. and spider web, located mostly (80%) in palm tree Astrocaryum aculeatissimum (Arecaceae), which represents a greater use of this species than expected by randomly. Most nests were found into a small core area of the study site, as well as the A. aculeatissimum thickets. The reproductive period occurred between September and February. In general, the egg-laying of P. idaliae was of two eggs (92%, n = 38) incubated between 14 and 16 days, with nestlings phase ranging between 17 to 21 days and growth rate of K = 35. The nests attentiveness by female decreased significantly with the nestlings age. General aspects of reproductive biology of P. idaliae were more similar to Phaethornis ruber and P. longuemareus, which may reflect phylogenetic or allometric relationship among these species. Daily survival rate (DSR = 0.953) did not differ between eggs and nestlings stages, and was similar to other hummingbirds species. However, rates were higher than found in other bird in restinga habitat close to the study area. Similar to other Neotropical studies, predation was the main cause of failure both periods 2014-2015 (77.8%) and 2015-2016 (53.3%). Parental care in P. idaliae had a high intra-specific variation, which cannot be explained by the environmental variables tested in this study. Therefore, other variables, such as food availability near the nests and its possible relationship to rainfall should be considered in future studies to try explaining the results found in this work, as well as causes of intraspecific variation in parental care by hummingbirds found in other studies