A victim of brood parasitism, an Eurasian Reed Warbler (Acrocephalus scirpaceus) feeds a Common Cuckoo (Cuculus canorus) nestling. The decline of Common Cuckoo means that this behaviour is becoming less common across Europe.
Photo: Per Harald Olsen (Wikimedia Commons)
A new paper in Nature Communications, Population Decline is Linked to Migration Route in the Common Cuckoo, by Hewson et al shows that Common Cuckoos (Cuculus canorus) take two different routes from Europe to their African wintering grounds during autumn migration. The researchers used satellite telemetry to track birds in virtually real time as they made their way south. The data showed that birds which took the shorter route experienced higher mortality rates than birds that took the longer route. This differential mortality correlated to population declines on the British breeding grounds. It's further evidence that effective conservation of migratory birds must take into account migration ecology as much as breeding and wintering site ecology.
