Hornbill abundance and habitat correlates in Kali Tiger Reserve, Western Ghats, India-Insights from collaborative monitoring

Abstract

1.The future of species, particularly large-bodied birds, under climate threats, is increasingly unclear. Protected areas (PAs) can mitigate the impacts of global change, but are not completely immune. This makes it imperative to monitor populations even inside PAs. In the forests of the Western Ghats, three hornbill species are found--Malabar Grey Hornbill, Malabar Pied Hornbill and Great Hornbill. Kali Tiger Reserve, of Karnataka state, India, is known for its healthy hornbill populations, yet few systematic surveys have attempted to estimate their abundance, distributions and habitat affiliations. In this study, we documented the distributions of the three hornbills, estimated the density of Malabar Grey Hornbills and assessed correlates of hornbill encounter rates within the reserve. Malabar Grey Hornbills were the most abundant and widely distributed, found in all ranges of the reserve. Gund, Kadra and Phansoli had the most detections of Malabar Pied and Great Hornbills. Encounter rates of Malabar Grey Hornbill were positively correlated with food-tree stem density, those of Malabar Pied Hornbill negatively correlated with basal area, while those of Great Hornbill not significantly associated with any variable. Malabar Grey Hornbills had a density of 5.1 per km2 (mean flock size = 1.2). While encounter rates of Malabar Pied and Great Hornbills were low, these numbers track the breeding season, when vocal activity is low and females are inside nests. This survey represents a partnership between researchers and the Karnataka forest department, aimed towards inculcating the collaborative spirit of research and monitoring.