Study: Cuckoos 'imitate' birds of prey to gain access to nests

CAMBRIDGE, England, Oct. 16 (UPI) -- Cuckoos have evolved to match the colors of hawks to frighten birds into briefly fleeing nests, allowing the cuckoos to lay their eggs, British researchers say.

Barred patterns on a cuckoo's breast may allow it to impersonate dangerous birds of prey such as sparrowhawks to frighten other avian hosts into leaving their nests exposed, report scientists at the University of Cambridge who used digital image analysis techniques to simulate "bird vision" and its sensitivity to certain color spectra.

A wide variety of cuckoos have adapted different plumage patterns depending on the area they inhabit so that they match a local bird of prey species, the researchers found.

"There is no benefit in looking like a dangerous species your target is not familiar with," lead researcher Thanh-Lan Gluckman from Cambridge's Department of Zoology said.

The "hawk impression" allows cuckoos to go "under the radar," undetected as they scope out potential nests in which to deposit their eggs, the researchers said.

"The barring on their plumage helps cuckoos conceal themselves while searching for potential nests, then when they approach, the host of the nest may mistake a cuckoo for a raptor coming to get them -- giving them unfettered access to lay eggs," Gluckman said.