The response of willow grouse chicks to auditory stimuli 3. Recognition of the incubating hen's voice

Willow grouse chicks were removed from the nests of captive hens, either at hatching or less than 24 hours later. They were tested for their ability to discriminate, and preference for, the voice of the hen which had incubated them, and the voice of another hen grouse. The chicks removed at hatching approached and tried to nestle under the loudspeaker playing the calls of their own hens. The chicks which had remained with their hens and been brooded by them were indifferent to the recording of their voices, but tended to avoid the voice of the unknown hen.