Meeting Abstract
Hummingbirds, like songbirds, are thought to be vocal learners. However, our understanding of vocal learning in hummingbirds is still in its early stages. Because of the independent evolutionary origins of vocal learning in hummingbirds, what we know of songbirds may not be applicable to hummingbirds. In a previous study, I found that Costa’s hummingbirds (Calypte costae) require a live adult tutor in order for vocal learning to take place in a lab setting. It was also found that Costa’s hummingbirds are capable of learning songs similar to their species-specific song but unable to learn the song of their sister’s species, the Anna’s hummingbird. In two follow-up experiments on open-ended learning and the sensitive phase of learning were examined. Costa’s hummingbirds, from a previous isolation experiment, were moved from acoustic isolation to an outdoor aviary where the birds were exposed both acoustically and visually to other hummingbirds and other species of birds. The songs of the birds were periodically recorded and examined to see if their song stayed the same or changed post exposure to other birds. To examine the sensitive phase of vocal learning, young male Costa’s were taken into captivity and reared in a controlled acoustic environment. The young males were tutored at two different periods of time, the first group received “early” tutoring from day 35 to 65 post-hatch and the second group received “late” tutoring from day 75 to 105 post-hatch. The birds were tracked and then their song ontogeny was monitored. These two experiments so far have shown that Costa’s hummingbirds are in fact open-ended learners, and that the sensitive phase of learning may in fact extend throughout both the early and late tutoring periods. Future experiments are necessary to define when the sensitive period of learning is for the Costa’s hummingbird.
