Duped Fowl May Get Egg on Their Faces

The greater prairie chicken, an endangered species in Illinois, is falling victim to a fowl con.

Prairie chicken hens are abandoning their own eggs when pheasant eggs--furtively slipped into prairie chicken nests by female pheasants--hatch before their own offspring.

“Right now, it’s a real problem we’re trying to deal with. But so far, anything we’ve tried hasn’t worked,” said John Buhnerkempe, associate biologist with the Illinois Natural History Survey.

Left in Their Care

Terry Musser of the state Conservation Department’s wildlife resources division said pheasant hens are laying eggs in prairie chicken nests and then leaving the nests--and the pheasant eggs--to the care of prairie chickens.

But pheasant eggs need only 21 to 22 days of incubation to hatch, while the prairie chicken needs 23 to 24 days, Musser said.

Once the pheasant eggs hatch, the prairie chicken takes the pheasant chicks as her own and leaves the nest--causing the incubating prairie chicken embryos to die, he said. “The prairie chicken hen is essentially fooled by the pheasant.”

The parasitic behavior by the pheasant has cut prairie chicken proliferation by about 20% in recent years, said Buhnerkempe. There are only about 220 of the birds left in Illinois, where once there were millions.

Similar to Grouse

The birds, similar to grouse, are confined mostly to sanctuary areas in southeastern and southern Illinois.

Buhnerkempe said the pheasant trickery first was noticed in the early 1970s, and has worsened in the last eight years as the pheasant population--aided by good ground cover and the sanctuaries’ no-hunting rule--has grown.

Biologists have attacked the problem by finding prairie chicken nests and removing pheasant eggs. They also have put out dummy nests containing game-farm eggs to try to draw the pheasants away from the prairie chicken nests.

But trapping is difficult and can upset the birds’ ecological balance.