Reed Warblers Form “Neighborhood Watch” To Spot Cuckoos

Plants and Animals





Photo credit:

A cuckoo chick ejecting a reed warbler egg from a warbler nest. Richard Nicoll

A common cuckoo (Cuculus canorus) female lays her egg in the nest of another bird, and after it hatches, the cuckoo chick typically pushes out the host bird’s own eggs. But now, communities of reed warblers (Acrocephalus scirpaceus) have developed a "neighborhood watch" in their marshlands to keep would-be victims up to date with the latest parasitic cuckoo threats.