Vocalizations and Copulatory Attempts in Free-Living Brown-Headed Cowbirds
Audiospectrograms of vocalizations recorded during 12 copulatory attempts by male Brown-headed Cowbirds (Molothrus ater artemesiae) are presented. All vocal sequences during copulatory attempts included songs, and all but one included flight whistles. In addition, a vocalization not previously described in cowbird copulatory sequences, the Kek Note, was recorded in four instances. Analysis of flight whistles indicated that they did not differ from flight whistles given in other contexts. The functional aspects of producing multiple types of vocalizations during the copulatory attempts are discussed. For example, incorporation of flight whistles during copulatory attempts may reflect conflicting tendencies to approach and to fly off during these times of heightened sexual arousal. Alternatively, flight whistles may have a direct stimulatory effect on the female's willingness to mate.
Dufty, Alfred M. Jr. and McChrystal, Richard. (1992). "Vocalizations and Copulatory Attempts in Free-Living Brown-Headed Cowbirds". Journal of Field Ornithology, 63(1), 16-25.