Environmental News Network - Birds Are Shrinking as the Climate Warms

Details: By Yale Environment 360; 09.May

As temperatures rise, birds’ bodies are growing smaller, but their wings are growing longer.

As temperatures rise, birds’ bodies are growing smaller, but their wings are growing longer. A new study finds this shift is most pronounced among the tiniest species.

For the research, scientists analyzed four decades of data gathered from migrating birds in Chicago and non-migrating birds in the Amazon rainforest. In both places, birds grew smaller and longer-winged over time, a shift that would help them to stay cool in warmer weather. The new analysis, published in the Proceedings of the National Academy of Sciences, found that smaller birds shrunk faster.

One possible explanation is that smaller species tend to reproduce on shorter time scales — the span of one generation is shorter for a mouse, say, than it is for an elephant — and, as such, they are able to evolve faster. But the new study found no link between generation length and changes in body size.

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Birds Are Shrinking as the Climate Warms — and Small Birds Are Shrinking Faster