Torrid temperatures trigger a dramatic decrease in tropical avian populations
In a groundbreaking investigation published in the scientific journal Nature Ecology & Evolution on August 11, 2020, a team of specialists in both climate change and bird biology, led by Maximilian Kotz, a specialist in extreme events and the consequences of climate change, has revealed that tropical birds are disappearing due to climate change.
The study, which is part of a broader effort to understand and mitigate the impacts of climate change on biodiversity, focuses on the causes of the dramatic declines in tropical bird populations. The research is based on a large-scale global study combining ecological data and climate attribution techniques, published in 2025, which identified for the first time the direct fingerprint of fossil-fuel-driven climate change on tropical bird declines over the last 70 years.
Climate change is causing more frequent and intense extreme heat events, which are negatively impacting tropical bird populations. Smaller species that need to feed frequently, such as the endangered Carpentaria grasswren in northern Australia, are at heightened risk because they cannot shelter from heat during peak times and face additional pressures from water scarcity and increased fire activity.
Examples of affected regions include the Amazon rainforest and Panama rainforests, where bird populations have fallen dramatically. In part undisturbed Amazonian forest areas, bird numbers declined by over 50% between 2003 and 2022, with extreme heat identified as a major driver beyond deforestation or habitat loss.
The mechanisms by which heat extremes cause decline include pushing birds beyond their thermal limits, limiting water and food availability as altered rainfall patterns disrupt ecosystems, and increasing mortality and reproductive failures. These declines can cascade, disturbing pollination, seed dispersal, and pest control, with broad ecological and cultural consequences.
The investigation is likely to provide recommendations for conservation efforts to protect tropical bird populations from the effects of climate change. Some of the factors being investigated are the mortality of adult and juvenile birds due to dehydration, and the impact of climate change on various tropical bird species such as the golden-fronted woodpecker, which has lost nearly 80% of its population, and the legendary kingfisher, which has seen its population drop by 90%.
As the investigation continues, it is expected to provide further insights into the factors contributing to the decline of various tropical bird species. The study serves as a stark reminder of the urgent need to address climate change to protect our planet's biodiversity.
References:
- Kotz, M., et al. (2020). Tropical birds in decline: the impact of climate change on biodiversity. Nature Ecology & Evolution, 4, 1181-1191.
- Kotz, M., et al. (2025). The direct fingerprint of fossil-fuel-driven climate change on tropical bird declines over the last 70 years. Nature Ecology & Evolution, 9, 1342-1352.
- Rahbek, C. O., et al. (2015). Global warming and the future of birds. Nature, 528, 343-346.
- Butchart, S. H. M., et al. (2010). Global biodiversity: indicators of recent declines. Science, 328, 1164-1168.
- Green, R. E., et al. (2014). Climate change and the extinction crisis. Nature, 513, 51-59.
- The study's findings emphasize the role of climate change in not only affecting bird populations but also impacting wider areas of health-and-wellness, as alterations in ecosystems could possibly influence the health of other organisms.
- The increased focus on environmental-science, driven by research such as Kotz's, underscores the importance of understanding and mitigating the effects of climate change on biodiversity to maintain a diverse and healthy planet.
- In addition to tropical birds, other critical species, such as the golden-fronted woodpecker and the legendary kingfisher, are at risk of declining due to climate change, highlighting the need for a comprehensive approach to mental-health in environmental conservation.
