Ecological impacts of poultry waste on urban raptors: conflicts, diseases, and climate change implications amidst pandemic threats

Abstract

1. The dramatic increase in poultry production and consumption (PPC) over the past decades has raised questions about its impacts on biodiversity, particularly in the Global South. This study focuses on the ecological and environmental impacts of PPC waste metabolism at Asia's largest livestock wet market, located next to the continent's largest landfill of Ghazipur in Delhi, which I have been monitoring since 2012. 2. Daily processing of >100,000 poultry fowls at Ghazipur results in annual production of ~27,375 metric tonnes of poultry waste, attracting massive flocks of Black-eared kites, and migratory facultative scavengers that winter in South Asia. Approximately >33,600 kites foraged in the area every day and disposed of 8.83% of the total PPC slaughter remains produced during October-April. However, with their return migration to Central Asia, kite flocks over Ghazipur reduced by 90%, leading to a proportional decrease in scavenging services. The absence of kites from the larger, migratory race during May-September did not elicit any compensatory response from the small Indian kite, whose numbers over landfill remained unchanged. Bearing in mind the prevalence of ritual feeding of meat chunks to kites in Delhi, my research indicates how life-history traits (migratory vs. resident) enable the exploitation of specific anthropogenic resources, creating distinct kite-niche(s). Other opportunistic scavengers, e.g., dogs, rats, cattle-egrets, several passerines, and livestock (fishes and pigs) also benefited from PPC waste. 3. Public health and ethical concerns, including Avian-influenza outbreaks in 2018-21 and pandemic lockdowns from 2020-22 - that affected informal meat processing - reduced the flocking of kites at Ghazipur by altering spatial dispersion of PPC remains. 4. Waste-biomass-driven cross-species associations can exacerbate zoonotic threats by putting humans and animals in close contact. The ecological and climatic impacts of waste-based biomass, as well as the aerospace conflicts caused by avian scavengers that cause birdstrikes, must factor in the integrated management of city waste. The quantity, type, dispersion, and accessibility of food waste for opportunistic urban fauna in tropical cities along avian migratory pathways are crucial for public health, and for the conservation of (facultative) migratory avian-scavengers like Eurasian Griffons and Steppe Eagles that are facing extinction threats.