Increase in shorebird nest predation tied to climate change

In 2015, we reported on a study that said climate change would adversely affect dozens of species of shorebirds by reducing breeding, stopover, and wintering habitat.

Now, researchers at the Universities of Bath and Sheffield say that shorebirds face another climate-related threat: increased nest predation. Today, they report in the journal Science that rates of daily nest predation in the Arctic, where many shorebirds breed, have increased threefold in the last 70 years.

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The “double whammy” of fewer chicks hatching and habitat-driven declines in adult survival has had a devastating effect on population numbers. The Spoon-billed Sandpiper, for example, has become critically endangered.

The authors analyzed data from 38,191 nests of 111 species in 149 locations across all continents.

The reasons for the increase in nest predation are unclear. The authors suggest it could be due to a shift in the diet of predators toward eating more eggs instead of other food sources or perhaps a change in predator species composition.

For example, lemmings, a key part of the Arctic food web, have experienced a crash in numbers due to reduced snow cover in the last several decades. With a lack of lemmings, predators may be searching for alternative prey in bird nests.

The authors also suggest that changes in vegetation or changes in behavior or distribution of nest predators such as foxes may also be factors contributing to the increased predation of shorebird nests.

“What is particularly striking about these results,” says co-author Robert Freckleton, “is that it is clear that nest losses to predators have risen really quickly in the Arctic over the past 20 years. This is particularly threatening for this group of birds as large numbers of species are declining anyway.”

“The Arctic, with recently elevated rates of nest predation, is no longer a safe harbor for breeding birds,” adds lead author Vojtěch Kubelka. “On the contrary, the Arctic now represents an extensive ecological trap for migrating shorebirds from a nest predation perspective.”

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