Factors driving breeding success of pallid harriers in Kazakh steppes

What is it about?

The Near-Threatened pallid harrier is a poorly known species whose core breeding areas are now restricted to Western Siberia and Kazakhstan. Here we showed that populations of this species showed a strong numerical response to the 6-year vole cycle. Timing of breeding, vole abundance and breeding habitat type affected breeding parameters. Early breeders had higher clutch size. Fledged brood size was higher in riverine steppes when voles were abundant but lower when voles were scarce.

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Why is it important?

Studying nomadic specialist predators is a real challenge because of their high mobility. Additionally, this is one of the first studies addressing predator-prey interactions in Central Asian steppes. Our results provided striking evidence that the timing of arrival on the breeding grounds, local variations in food abundance and their interaction with habitat composition and nest predation rates drive breeding success in a declining nomadic predator.