Factors Affecting Provisioning Times of Two Stork Species in Lowland Nepal

Abstract

The ecology of stork colonies in southern Asia are very poorly understood. Factors affecting provisioning times of adults were evaluated at nests of two stork species, the Asian Openbill (Anastomus oscitans) and the Lesser Adjutant (Leptoptilos javanicus), in lowland Nepal, where the landscape is dominated by multi-cropped agriculture fields. Analyses focused on understanding if provisioning times were influenced more due to colony-level variables, wetlands around colonies, or season. Using generalized additive mixed models and the information-Theoretic approach, colony-level variables (brood size and chick age) showed non-Trivial associations with provisioning times (substantially better than the null model). Univariate models with colony size and wetlands had poor support (worse than the null model). Season, which represented the changing cropping patterns, rainfall, and wetness on the landscape, was the most important variable for both species. The combination of season and wetlands was very important for provisioning Asian Openbills whose chicks fledged during the monsoon (July-October), but not for Lesser Adjutants whose chicks fledged in the drier winter months (November-February). Results strongly suggest that changing cropping patterns to a drier monsoonal crop, or reductions in wetland extents, will be detrimental to storks in Nepal.