An ecological study on nesting patterns and Behavioural dynamics of vultures in Kangra valley, Himachal pradesh

Abstract

Vultures are nature’s most efficient scavengers, playing a critical role in maintaining ecological balance. Their populations in India have suffered a drastic decline from 97-99% between 1993 and 2002, leading to the establishment of captive breeding programs aimed at species recovery. Threats of decline have now stabilized, but little is known about the ecology and survival of the vultures in the wild, necessitating this study for the conservation of vultures in their natural habitat. Kangra Valley, situated in the westernmost region of Himachal Pradesh state in India, is one of India's important vulture sites, supporting most of the nine vulture species recorded in the country. Among these, the White-rumped Vulture (Gyps bengalensis), Egyptian Vulture (Neophron percnopterus), Bearded Vulture (Gypaetus barbatus), Himalayan Griffon (Gyps himalayensis), and Eurasian Griffon (Gyps fulvus) are the most observed, while the Cinereous Vulture (Aegypius monachus), Red-headed Vulture (Sarcogyps calvus), Slender-billed Vulture (Gyps tenuirostris), and Indian Vulture (Gyps indicus) are recorded occasionally. Kangra is also one of the most densely populated districts of Himachal Pradesh, with an extensive road network, contributing to anthropogenic pressures on vulture populations. While the region has a long history of vulture census efforts, aspects of their breeding ecology remain poorly understood. Why do they select a particular tree for nesting? What are the variables that affect nest site selection? What is the nest success rate? Where do they move, and what is their home range? What are the threats? This study, conducted between 2019 to 2024, focuses on the breeding ecology of White-rumped Vultures in Kangra, examining their nesting preferences, reproductive success, threats to nesting colonies and spatial movements. Additionally, the research explores the climatic niche availability for all nine vulture species found in the region, assessing current and future climatic scenarios to predict potential habitat suitability. The Chir Pine forests of Kangra serve as the breeding habitat for White-rumped Vultures in the region. The breeding season of the White-rumped Vulture (Gyps bengalensis) in the area extends from November to April, encompassing mating, incubation, hatching, and fledgling development, lasting approximately 25-28 weeks (October—April). Over three consecutive breeding seasons (2021-2024), the study recorded 17 active nesting colonies with a total of 617 active nests, primarily in Chir Pine (Pinus roxburghii) trees. Nest site selection was influenced by tree characteristics, with vultures preferring trees with a larger girth at breast height (GBH) (average GBH of 254.8 cm + 49.3 SD), lower canopy cover (5-10%), greater shrub density (77-100%), and proximity to other nesting trees and water sources. Conversely, areas with high fire activity, dense canopy cover, and limited nearby trees were found to be less suitable. In addition to breeding ecology, the study identified 36 carcass dumping sites in the region. These sites, managed by local communities, serve as designated areas for livestock carcass disposal, primarily for cattle and buffalo. The carcasses are transported from households to the dumping sites by local cobblers, locally known as "Harijans." The decline of open carcass disposal areas has posed further challenges for vulture populations. To understand movement patterns, five wild White-rumped Vultures were satellite-tagged in Kangra, Himachal Pradesh, in 2021. The tagged individuals exhibited extensive movements, ranging across Jammu & Kashmir, the Pakistan border near Punjab, and Uttarakhand. Three of these vultures have consistently nested in Dolba and Lapiana within Kangra between 2021 and 2024. The study recorded an average home range of 1367.6 km? for non-breeding individuals and 1719.8 km? for breeding individuals across seasons. The future distribution for the nine vulture species shows a significant decline in the modeled climatic niche for seven vultures by 2041-2060 and 2061-2080. The study identified electrocution, forest fires and poisoning as major threats, with notable vulture fatalities recorded. Major forest fire-prone areas include Gopalpur, Pathiar Range, Lunj, and Baranj Sirmani. This study offered insights into India's largest documented aggregation of 617 White-rumped Vulture nests. The study recommends targeted conservation interventions to ensure the long-term survival of White-rumped Vultures. These include the protection of nesting sites, preservation of old-growth forests, and support for cobbler communities engaged in carcass disposal. Additionally, designated vulture feeding stations within forested areas should be established. Given these findings, the study proposes designating the region as a Vulture Safe Zone, suitable areas for releasing captive-bred vultures with continuous monitoring. Himachal Pradesh Forest Department (HPFD) and the Ministry of Environment and Climate Change (MoEFCC) have to come up with guidelines to declare a vulture safe zone as well as a strategic conservation plan to safeguard this critically endangered species.