There are signs of stabilisation among India's Critically Endangered vulture species, according to new survey results, although evidence of population recovery remains limited.
Historically some of the most abundant species of large raptor in the world, South Asian vulture populations underwent disastrous declines from the mid-1990s onwards, as a result of unintended poisoning by the veterinary drug diclofenac.
The worst-hit species, White-rumped Vulture, declined by a dreadful 99.9% in India between 1992 and 2007. As a result of these losses, three species – White-rumped, Indian and Slender-billed Vultures, were classified by IUCN as Critically Endangered.
White-rumped Vulture has suffered a disastrous decline in India (Ed Stubbs).
Conservation efforts
Diclofenac was banned in India and elsewhere in 2006. Furthermore, vulture numbers have been monitored on a regular basis to assess whether conservation efforts are having any impact on the status of populations.
Beginning in 1992, vultures in India have been surveyed along road transects, which involves driving along both major highways, and tracks running through protected areas, and counting any vultures encountered. The eighth such survey, which covered some 16,000 km of roads in 13 states, was carried out in 2022, and the results have recently been published.
Previous surveys up to 2015 had shown that the rapid declines that White-rumped and Indian and Slender-billed Vultures combined had experienced from the mid-1990s onwards had begun to slow down, with even some tentative evidence that populations of White-rumped had stabilised.
Vultures stablising
Numbers of Slender-billed Vultures have always been too low to quantify a reliable trend for this rare species. Survey results from 2022 confirmed that populations continued to remain stable, including Indian Vulture, which had shown signs of further declines in the 2015 survey.
Further evidence that populations have remained stable came from analysis of changes over time in the annual population multiplication rate, which was below one (indicating a population decline) in the early 2000s, but which hovered around one (stability) in later periods.
Despite populations of vultures remaining stable since the ban on diclofenac, much work remains to be done to ensure the future survival of these species. With population levels now at a fraction of what they once were, the species are still in a precarious situation.
Reference
Prakash, V, et al. 2024. Recent trends in populations of Critically Endangered Gyps vultures in India. Bird Conservation International. DOI: https://doi.org/10.1017/S0959270923000394
