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 firs t experiment, sexual displays were elicited from females by playback o f normal song and rearranged sequences of the component phrases. In a second experiment, male and female cowbirds discriminated among the sa me songs in a food-rewarded operant procedure. In a sexual context, th e 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 dif ferences in the results of the two experiments suggest that some aspec ts of cowbird song perception remain constant across motivational cont exts, whereas others are unique to particular motivational contexts.