SONG DEVELOPMENT BY BLACK-CAPPED CHICKADEES (PARUS-ATRICAPILLUS) AND CAROLINA CHICKADEES (PARUS-CAROLINENSIS)

Do songs of songbirds, which learn to sing, provide reliable clues to genetic identity in zones of secondary contact? How do some songbird s pecies maintain such highly stereotyped songs throughout extensive geo graphic ranges? These two questions were addressed with a study of son g development by Carolina and Black-capped chickadees (Parus carolinen sis and P. atricapillus). In one hand-reared, mixed group in the labor atory, male Carolina Chickadees produced better imitations of a tape-t utored Black-capped Chickadee fee-bee song than did two male Black-cap ped Chickadees. In another mixed group, a male Black-capped Chickadee produced a better imitation of tape-tutored Carolina Chickadee song el ements than did the Carolina Chickadee males themselves. Black-capped Chickadees in an additional experiment were tutored with normal fee-be e songs and with fee-fee, bee-bee, and bee-fee songs; these males also produced highly abnormal songs, although songs of males within groups converged on one another, reinforcing ideas that social interactions are crucial for the song learning process. These data thus reveal that song in secondary contact zones of these chickadees is probably not a good indication of genotype. The feat of Black-capped Chickadee song stereotypy in nature, together with other features of their singing be havior (e.g. social and hormonal determinants of singing, subsong by b oth sexes but loud songs only from males), remain both puzzling and fa scinating.