Chapter 2 - Timing of breeding

Abstract

Tropical birds, even at the same study site, have a great diversity of strategies for timing their breeding season. Breeding seasons of tropical birds are typically much longer than for temperate breeding birds because the minimum environment conditions for successful breeding are available for much of the year. Depending on the species, nesting may occur year-round, have a strong bimodal pattern, occur only in the dry season, or occur only in the rainy season. While breeding seasons often correspond to the time of year when food is abundant, there are many exceptions. Counterintuitively, some tropical passerines nest when food is scarce because this is the time of year when the risk of nest predation is lowest. Feather molt is an energetically costly life stage that follows breeding, is very prolonged in tropical birds, and could impose time and energy trade-offs that constrain the onset and termination of breeding. A major gap in our knowledge of the evolution of breeding seasons is the scarcity of experimental manipulations to test predictions and a lack of understanding of how variation in breeding timing affects fitness.