Bamboozling Interactions: Interspecific associations within mixed-species bird flocks in bamboo in the Eastern Himalaya

ABSTRACTBamboo, although widespread, is a globally understudied habitat, but supports significant biodiversity, including specialist bird species. Mixed-species bird flocks (flocks) are an important and regular feature of forest bird communities worldwide and have been well-studied. However, how and why flocks might differ between bamboo and non-bamboo habitats is unknown.We studied flocks and their arthropod prey in rainforest and bamboo stands across two seasons in the Eastern Himalaya. Using network analysis, we compared interspecific associations within flocks, and asked if resource availability (arthropod abundance) drives flocking.Bamboo and rainforest flocks were significantly different, with bamboo flocks being more cohesive, less modular and their species more interconnected. Further, bamboo flocks were more consistent in their composition across seasons whereas rainforest flocks partially disintegrated in spring, probably because of increased arthropod abundance. In bamboo, the loss of arthropods in an entire substrate and the increase in other substrates was potentially insufficient to cease flocking in spring.Resource availability and the unique foraging behaviour of the bamboo specialists likely drive flocking in the Eastern Himalaya bamboo. Our study is among the few to describe bamboo flocks and we emphasise conserving bamboo stands to ensure persistence of this unique flock in the Eastern Himalaya.