Heat Causing Sharp Declines in Bird Populations: Study

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Sydney: Climate change-induced heat extremes have caused a 25–38 percent decline in tropical bird populations since 1950, according to a study involving Australian scientists.

Researchers found that while changes in average temperature and rainfall have some effect, the most serious climate threat to birds—especially in tropical regions—comes from extreme heat events, according to an analysis released Tuesday on the University of Queensland’s website.

The study, conducted by Australian and European scientists, examined more than 3,000 bird populations between 1950 and 2020. Using weather records, they separated the impacts of climate change from other human pressures such as habitat loss, analyzing a dataset of 90,000 observations from across all continents.

Published in Nature Ecology & Evolution, the research confirmed earlier findings that extreme heat events have surged dramatically over the past 70 years, with the greatest increases near the equator. Tropical birds are now exposed to dangerously hot days around ten times more often than in the past.

Surviving birds face long-term harm, including organ damage, reduced breeding success, and declines in body condition. Extreme heat also disrupts foraging, stresses eggs and chicks, and can cause dehydration or nest abandonment.

The findings show that even remote, protected tropical forests free from direct human interference are witnessing heat-driven bird declines, with climate impacts now outweighing other threats.

Given that nearly half of all bird species live in tropical regions, researchers warn that these losses pose a severe risk to global biodiversity and call for urgent action to cut emissions and protect habitats.