Dreamstime /Netherlands Institute of Ecology NIOO-KNAW

ScienceShot: For Great Tits, Climate Change's Downside Leads to Upside

Liz is a staff writer for Science.

For great tits, climate change is turning out to be not as bad a deal as biologists first thought. For more than 40 years, a long-term study in the Netherlands has tracked when this common songbird lays its eggs, how many eggs hatch, and how many hatchlings survive to reproduce. In the past, the birds successfully timed their breeding with the peak emergence of caterpillars to have the most food available for their newborns. As the climate has warmed, both the caterpillars and the birds have advanced their spring schedules, but the birds have failed to keep pace with the caterpillars. Many are breeding almost 2 weeks too late, so there's not as much food around for their hungry babies. Consequently, fewer of their offspring survive. That's the bad news. But there's good news as well. Even with this loss, the number of great tits in the population studied has remained fairly stable, researchers report online today in Science. It turns out that with fewer young birds, there's less competition for scarce food, so more of those birds make it through the winter. Eventually, the mismatch between the birds and the caterpillars may become severe enough that the population of great tits does decline, but this buffering effect may slow that decline enough that the birds have time to evolve a way to catch up with the caterpillars.

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Posted in Plants & Animals, Climate