The feral chickens of Kauai provide a unique opportunity to study what happens when domesticated animals escape and evolve

Ewen Callaway in Nature:

“Don't look at them directly,” Rie Henriksen whispers, “otherwise they get suspicious.” The neuroscientist is referring to a dozen or so chickens loitering just a few metres away in the car park of a scenic observation point for Opaekaa Falls on the island of Kauai, Hawaii.

The chickens have every reason to distrust Henriksen and her colleague, evolutionary geneticist Dominic Wright, who have travelled to the island from Linköping University in Sweden armed with traps, drones, thermal cameras and a mobile molecular-biology lab to study the birds.

As the two try to act casual by their rented car, a jet-black hen with splashes of iridescent green feathers pecks its way along a trail of bird feed up to a device called a goal trap. Wright tugs at a string looped around his big toe and a spring-loaded net snaps over the bird. After a moment of stunned silence, the hen erupts into squawking fury.

Opaekaa Falls, like much of Kauai, is teeming with feral chickens — free-ranging fowl related both to the domestic breeds that lay eggs or produce meat for supermarket shelves and to a more ancestral lineage imported to Hawaii hundreds of years ago.

These modern hybrids inhabit almost every corner of the island, from rugged chasms to KFC car parks. They have clucked their way into local lore and culture and are both beloved and reviled by Kauai's human occupants. Biologists, however, see in the feral animals an improbable experiment in evolution: what happens when chickens go wild?

More here.