Birds lay eggs that match nesting ground

DUNDEE, Scotland, Jan. 17 (UPI) -- Ground-nesting Japanese quail are so adept at camouflage females "know" the pattern of their eggs and choose laying spots to hide them best, researchers say.

"Not only are the eggs camouflaged, but the birds choose to lay their eggs on a substrate that maximizes camouflage," P. George Lovell of Abertay University in Scotland said.

Female quail lay eggs that vary a lot in appearance, and those differences are repeatable, researchers found.

Some birds consistently lay eggs covered in dark spots; others have many fewer spots or, in some cases, almost none at all.

To test the idea birds might make optimal egg-laying choices based on the special characteristics of their own eggs, the researchers gave female quail in a lab experiment a choice between four different backgrounds on which to lay their eggs.

The experiments revealed that most quail mothers lay their eggs on background colors to match the spots on their eggs.

"Animals make choices based upon their knowledge of the environment and their own phenotype to maximize their ability to reproduce and survive," Lovell said. "In this specific case, birds know what their eggs look like and can make laying choices that will minimize predation."

The findings have been published in Current Biology.