Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

作者：Yuanxing Ye, Canshi Hu, Yiting Jiang, Geoffrey Davison, Changqing Ding · 发表于：Avian Research · 年份：2021 · DOI：10.1186/s40657-021-00264-7 · 被引用次数：17 · 研究领域：Avian ecology and behavior、Wildlife Ecology and Conservation、Ecology and Vegetation Dynamics Studies

Abstract Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret ( Egretta garzetta ) and Cattle Egret ( Bubulcus ibis ) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), w...