Breeding success of long-billed vulture (Gyps indicus) and its drivers in Deccan Plateau, India

Manchiryala Ravikanth, Aamer Sohel Khan, Selvarasu Sathishkumar, Nagarajan Baskaran, Ram Mohan Medishetti, Arockia E J Ferdin

Vultures struggle to breed owing to increased exposure to toxic materials, reduced nesting sites and changing weather conditions. Breeding success determines the fate of bird populations; thus, understanding the determinants of breeding success is vital, especially for critically endangered species like Gyps species, whose populations have been decimated across Asia due to the rampant use of diclofenac. Despite their declining trend, data on vultures’ breeding are limited. Between 2010 and 2023, monitoring the reproductive performance and the covariates that influence it, we assessed the drivers of breeding success in Long-billed Vultures (LBV) Gyps indicus in the Deccan Plateau, India. Over 14 years, we monitored 23 nests in two breeding colonies and found that 161 occupied pairs of LBV laid 116 eggs, of which 85 fledged successfully. The reproductive performance recorded over 14 years showed a significant declining trend. Inter-annual variations in breeding success compared with corresponding period’s environmental covariates showed that breeding success decreased with the toxic levels in effluent discharge from paper industry and increased with wind speed. Inter-nest variations in nest success compared with corresponding nest and nest-site covariates, revealed that nest success increased with nest depth and was higher in nests with vegetation cover than those without the same, but decreased with distance from the top of the cliff to nest. Overall, our study indicates that effluent discharge into the Peddavagu stream by the Sirpur paper industry is a key negative driver of LBV breeding success. We suggest, measures to filter hazardous substances at the Sirpur paper industry, conducting detailed toxicological studies on vulture carcasses and initiating new studies on LBV breeding ecology in potential areas, as these can provide critical insights.

Publication European Journal of Wildlife Research. 2025

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