Breeding biology of the Grey-headed Bulbul Pycnonotus priocephalus (Aves: Pycnonotidae) in the Western Ghats, India

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P. Balakrishnan

Abstract

The breeding biology of the endemic Grey-headed Bulbul Pycnonotus priocephalus was studied from 2003 to 2005 in Silent Valley National Park, Western Ghats, India. Nests were located during three field seasons from the arrival (December) to the dispersal of the birds (June) and collected data on various breeding parameters, availability of fruits and weather conditions. All nests were found in mid-elevation evergreen forests ranging from 900 to 1,400 m elevation. Breeding occurred in the drier months (January-May), which coincides with high fruit availability. Nest building lasted 3-8 days. Majority of the nests (72%; n = 39) were built on two plant species (Ochlandra travancorica and saplings of Syzygium sp.) and the mean nest height was 1.52 plus or minus 0.80 m (n = 52). Nests were randomly oriented around the nesting plants with a mean vector of orientation equaling 160.450. The clutch size averaged 1.53 plus or minus 0.50 eggs (range = 1-2; n = 47). Incubation and nestling periods were 13 plus or minus 0.87 (n = 9) and 12 plus or minus 0.50 (n = 9) days, respectively. Overall nest success was 10.79%. Nest success rates varied among incubation and nestling periods. Grey-headed Bulbul exhibit life-history traits associated with low productivity such as short breeding season, low clutch size, fewer broods per year and high predation rates indicating that deterioration of breeding habitats might seriously hamper the long-term survival of the species.

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Communications
Author Biography

P. Balakrishnan

Dr. P. Balakrishnan was a Research Fellow at SACON, Coimbatore. He is also associated with the Wildlife Research and Conservation Trust, Nilambur. His research interests include ecology and conservation of threatened and fragmented populations, wildlife-habitat relationships, human and climate change impacts on the demography and life-history strategies of birds.