EFFECT OF MOTIVATIONAL CONTEXT ON CONSPECIFIC SONG DISCRIMINATION BY BROWN-HEADED COWBIRDS (MOLOTHRUS ATER)

Two experiments to examine the effects of motivational context on the perception of conspecific song by cowbirds were conducted. In the first experiment, sexual displays were elicited from females by playback of normal song and rearranged sequences of the component phrases. In a second experiment, male and female cowbirds discriminated among the same songs in a food-rewarded operant procedure. In a sexual context, the birds were sensitive to both the beginning and end phrases of normal song, whereas in a food context, the birds were more sensitive to the beginning of normal song. In both experiments, one-phrase songs were better discriminated from normal song than two-phrase songs, and there was no effect of phrase order on discrimination. Similarities and differences in the results of the two experiments suggest that some aspects of cowbird song perception remain constant across motivational contexts, whereas others are unique to particular motivational contexts.