BREEDING ECOLOGY OF THE CRESTED SERPENT EAGLE Spilornis cheela (LATHAM, 1790) (AVES: ACCIPITRIFORMES: ACCIPITRIDAE) IN KOLLI HILLS, TAMIL NADU, INDIA

Abstract

The breeding ecology of the crested serpent eagle (Spilornis cheela), focusing on nest-site selection, food habits, and perch-site preference, was studied in the Kolli Hills of Tamil Nadu, India, from May 2005 to May 2010. Thirty-two active nests were located, with nest-site details collected from 27 nests that were accessible. The crested serpent eagle did not construct new nests, but did renew or alter old nests, mainly in December. Both sexes were involved in the nest renewal activities. The clutch size was one, the mean incubation period was 41.5 days, and the mean fledging period was 64.5 days. Nests were found largely along riverine patches. The results indicate the mature and less disturbed riverine forests with large sized trees are critical for the breeding and conservation of this species. The food habits of the eagle were known from prey items brought into the nest by the adult to feed the chick and prey items fed on by the adult. In total, 173 feeding observations were made and the prey items belonged to 17 species of vertebrates. The crested serpent eagle largely preferred reptiles, which accounted for 74% of their diet, followed by birds, which accounted for 18% of their diet. A total of 1237 perching records were observed. The crested serpent eagle preferred to perch on the outer canopy of the trees found largely in the forest edges.