Characteristics, Use and Possible Functions of the Perch Songs and Chatter Calls of Male Common Yellowthroats

Abstract

The vocal repertoire of male Common Yellowthroats (Geothlypis trichas) includes a single distinctive perch song, a flight song, and several calls, including a chatter call. To ascertain the function of perch songs and chatter calls and to determine if these vocalizations are altered to convey different information, I examined the singing and calling behavior of male yellowthroats throughout the breeding cycle and in different behavioral contexts. The singing behavior of males changed in two ways after pairing: singing rates declined, suggesting that perch songs play a role in mate attraction, and most songs were uttered with reduced volume. These low volume songs appeared to be directed at mates, perhaps serving to stimulate ovulatory cycles, elicit copulation solicitation, or provide information about potential predators. Male yellowthroats uttered regular volume songs at low rates after pairing, suggesting that their function is not limited to mate attraction. Regular volume songs uttered after pairing appeared to be used in both intrasexual and intersexual contexts. The use of chatter calls did not decline until after females began incubating, and most were directed at conspecific males in aggressive (territorial) contexts. Male yellowthroats typically uttered longer perch songs (more phrases per song) during the nest building/egg laying and incubation/nestling periods, however, the possible function of these longer songs is unknown. My results provided no other evidence that male yellowthroats convey motivational information by varying the temporal and frequency characteristics of either perch songs or chatters