Tropical rainforests are being lost and degraded at alarming rates today. One of the most important needs in conservation biology therefore is to find out what component of the original diversity we can conserve and what we are likely to lose in smaller altered tropical forests. Today we have fairly good answers for entire communities and many individual species. The effects of tropical forest loss and degradation on behaviour, social systems, and species interactions are still largely unknown. This study looked at one such social system, namely mixed-species flocks of birds, in a fragmented tropical rainforest in the Indira Gandhi Wildlife Sanctuary in the southern Western Ghats, India. Nine rainforest fragments in a plantation matrix of primarily tea were sampled for mixed-species flocks from December 2004 to April 2005. A total of 87 bird and 3 mammal species participated in 245 flocks seen across all fragments. Differences in sizes, frequency of occurrence and composition of flocks were recorded between fragments. The average number of species participating per flock however did not vary much between them. Habitat structure, local bird species pool and area of the fragment emerged as important predictors of different measures of mixed-species flocking. The number of species and individuals of rainforest birds in a flock were strongly related to habitat structure, the composition of flocks and participation of open-country species were related to the local species pool and frequency of occurrence of flocks was related to fragment area. The study showed that social systems such as mixed-species flocking can be maintained even in fragments of rainforest as long as the habitat remains intact but flocks are likely to disintegrate in very small fragments irrespective of the quality of the habitat or the local species pool
 

M. Sc. Dissertation :

Patterns in mixed species flocking of birds in rainforest fragments of the southern Western Ghats - Hari Sridhar