Patterns of nesting and nest success in an evergreen forest in Southeast Asia

Southeast Asian forest birds are threatened by the highest rate of tropical deforestation globally, but conservation efforts regionally have very limited information from which to make policy and management plans. To provide baseline data on nesting and nest success for forest birds from an intact forest, we monitored 1506 nests of 54 species during 2003–2011 in a seasonally wet forest at 14°N in north-eastern Thailand. We estimated daily nest survival (DSR) for 37 species (n = 1082 nests). Early nesting species were more successful and ground-nesting birds had higher DSR (0.962) than above-ground nests (0.934). DSR for 13 focal species (n = 956 nests) varied from 0.842 to 0.975. In general, DSR was unrelated to season or nest height for focal species although one species was more successful early in their breeding season while for another, higher nests were more successful. Nest survival was low, and predation accounted for 92% of nest failures. Two nest predators, Northern Pig-tailed Macaque Macaca nemestrina and Green Cat Snake Boiga cyanea accounted for 43.7% and 21.8% of the predation events, respectively. We suggest that local conditions, even in intact forests, may produce complex dynamics for reproductive success of breeding birds, and we posit that presence of the dominant nest predators was largely responsible for patterns we observed among species, particularly the higher DSR of ground-nesting birds. Our data further support the idea that DSR is generally lower in relatively undisturbed sites in the tropics than similarly undisturbed sites in the temperate zone.