Songbirds’ Elaborate Cries For Food Show First Signs Of Vocal Learning:
"ScienceDaily (July 27, 2009) — Only a handful of social animals — songbirds, some marine mammals, some bats and humans — learn to actively style their vocal communications. Babies, for instance, start by babbling, their first chance to experiment with sounds. Now, new research in songbirds shows that vocal experimentation may begin with their earliest vocalizations — food begging calls — and perhaps for a more devious reason than previously believed. The findings could change the way we think about the evolution of vocal learning."
It may have started as cheating,” says Fernando Nottebohm, head of the Laboratory of Animal Behavior at The Rockefeller University. “By generating a diversity of calls, young birds may trick their parents into losing track of whom they last fed, in effect creating the impression of several individuals.” In this scenario, the most agile vocal dissembler would get more than its fair share of food at the expense of its siblings.
Nottebohm and Wan-chun Liu, a research assistant professor who made the original observations, are quick to say that the interpretation remains speculative for now, but if true, it would complicate the conventional wisdom that vocal learning evolved as an adjunct to reproductive behavior. In temperate climates, most often only male songbirds sing. The message conveyed by song is simple: I am a male robin, mature, single and ready to breed; females are welcome, males stay away. Depending on the listener, song is a lure or a threat. By imitating the song of established seniors with whom they would have to compete, young breeders presumably gained an advantage in courtship and territorial defense.The vocal imitation expressed by adults, however, is a complex behavior requiring sophisticated underlying brain circuits, Nottebohm says. How would birds with only innate, genetically foreordained vocal repertoires have evolved the ability?
. . .
Males producing food begging calls also showed an increased expression of c-fos, a neural activity marker in a section of the forebrain known as the robust nucleus, which later plays a role in the control of learned song.
Here's how that plays out with scientists who study human languages.
Scientist at Work: Tucker Childs
Linguist’s Preservation Kit Has New Digital Tools
New York Times July 28. 2009