Siberian redstarts move their nesting sites closer to or even inside human settlements when cuckoos are nearby. An article about this is published in Current Biology.
Cuckoos lay their eggs in the nests of other birds, using the efforts of the owners for their own reproduction. “Foster parents” invest resources in raising the offspring of another bird at the expense of their own chick. This strategy is called brood parasitism and is detrimental to exploited species.
In a series of observations and experiments conducted by scientists at the Institute for Biological Intelligence of the Max Planck Society, it turned out that some birds are able to adapt and change their usual habits in order to protect themselves from cuckoos. Passerines are typical prey for cuckoos in northeast China . The Siberian Redstart breeds twice a season – once before and once after arriving in the cuckoo region. Cuckoos are different in that they usually avoid close contact with people.
The researchers found that redstarts moved their nests closer to human settlements during their second laying period, presumably to scare away the cuckoos. The scientists were then able to induce the same behavior during the first egg-laying period by mimicking cuckoo calls through speakers. Mimicking the presence of cuckoos caused redstarts to move their nests closer to buildings or even breed indoors. This is in line with their natural behavior during the second laying period when cuckoos are actually present.
“For the first time, we were able to experimentally show that Siberian redstarts adapt their nesting behavior depending on whether they notice cuckoos in the area,” the authors summarize.
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