Patterns of species participation across multiple mixed-species flock types in a tropical forest in northeastern India

Abstract

We studied mixed-species bird flocks in northeastern India to (a) develop a framework for quantifying species participation in mixed-species flocks, (b) characterize the ecology and behaviour of participant species, and (c) explore mechanisms influencing the coexistence of different mixed-species flock types. To characterize participation in mixed-species flocks, we implement a new method incorporating species abundances, minimizing potential biases in measuring participation arising from differences in the availability of flocking species. There are at least three distinct flock types in the lowland forests of northeastern India; these flock types differ in the body mass and vertical stratum use of participant species. The “core” of mixed-species flocks was composed of a species group that differed much more in their foraging method in comparison with “attendant” species. The exchange of benefits and minimization of interspecific competition might lead to, and maintain, heterogeneity in foraging methods among core species of mixed-species flocks.

Keywords:

• core species
• feeding guild
• insectivore
• mixed-species flock
• attendant species

Acknowledgements

We thank the Wildlife Conservation Society – India Programme for financial support and the National Centre for Biological Sciences and Centre for Wildlife Studies for administrative support. We thank Pantha, Aphu and Khichaye Yobin for their enthusiasm in the field. We are grateful to the Arunachal Pradesh Forest Department for providing permission to carry out this research.