Warming planet changing reproduction rates in birds


A study looking at the impact of climate change on bird reproduction has found an overall decline in annual offspring production during a 50-year period.

Published in Proceedings of the National Academy of Sciences, the research assessed the findings of previous studies in a powerful statistical tool known as a meta-analysis. The findings, based on 201 wild bird populations examined between 1970 and 2019, revealed that the overall reproductive output of birds had declined. 

The study found that Common Eider offspring production has declined since 1970 (Fausto Riccioni).

However, small-bodied and sedentary species experienced an increase in offspring production, indicating they may benefit from a warming climate, whereas large-bodied and migratory species showed reduced offspring production, suggesting they may suffer due to rising temperatures. These are general trends and the team cautions that there were many exceptions.

The authors of the paper suggest that migratory species may find it difficult to adapt to a rapidly changing climate in their breeding and wintering areas, while large birds may have problems adapting to changing climate conditions because they tend to live a 'slower pace of life' and have offspring only once a year.

Among the small-bodied species that showed an increase in offspring production were Reed Warbler and Pied Flycatcher, with some of the large-bodied species that showed a general decline including Montagu's Harrier and Common Eider.

The team found 57% of bird populations showed a declining trend in offspring production over time whereas 43% of populations produced more offspring.



Arlt, D, Halupka, L, & Tolvanen, J. 2023. The effect of climate change on avian offspring production: A global meta-analysis. Proceedings of the National Academy of Sciences. DOI: doi:10.1073/pnas.2208389120