Abstract:
Patterns of resource partitioning among 4 sympatric sturnids: [black-collared starling (Sturnus nigricollis), pied starling (S. contra), common myna (Acridotheres tristis) and crested myna (A. javanicus) were determined based on their food habits, foraging and nesting microhabitat selection, morphology and behavior. The study was
conducted from March 1986 to June 1988 at and around Bang Pra Game Sanctuary, Cholburi, Thailand. Diets of adults and nestlings of all species were significantly different. The 4 species exhibited significant differences in morphology, primarily in trophic (bill shape and length) and locomotive (wing shape and size) appendages that affect selection of foraging microhabitat and hence choice of diets. Selection of nest site characteristics was significantly different among the species and was associated with types of tree i.e., palm vs non-palm (trees with forks or branches), distance of nest tree from human habitation and distance of nest tree from seasonal or permanent waters. The pied starling, common myna and crested myna all
selected different foraging habitats and used different techniques for foraging,-however the black-collared starling shared foraging habitat with the other 3 species. Breeding success, breeding chronology, and clutch sizes were similar for the 4 species. These 4 sympatric sturnids partitioned their resources through differences in morphology, which, in turn, affected their foraging habitat selection and modes of foraging, and
hence, differences in diet. Behavioral differences also segregated their foraging techniques and nest site selection.
