英語(yǔ)聽(tīng)力文摘 Learning to Sing
The complex vocalizations of songbirds are learned, not inherited. Some even
have regional accents.
Wrens, thrushes and other songbirds don't hatch with their impressive musical
talents. They learn to sing their extensive repertoires by listening to others
of their kind.
Donald Kroodsma is the author of a new book, 'The Singing Life of Birds.'
Kroodsma says many birds seem to come naturally equipped with basic sounds and
even some very simple songs. The eastern wood-pewee is an example.
'We've done some experiments showing that those songs are pretty much encoded in the DNA. But as a result, it's a pretty limited repertoire of, oh, in the
eastern wood peewee, of up to three different songs. But all the songbirds, when
we think of songbirds, we think of wrens and warblers, robins, thrushes,
sparrows, all the birds that make so much racket, these are the songbirds that
have very special groups of neurons in the brain, and most of them imitate
precise details of songs just like you and I learned our native language.'
Kroodsma says birds even share our tendency toward regional dialects.
'When birds learn songs at a particular location and stay around at that
location, regional dialects tend to develop. They have the same kind of dialects
that develop in human speech.'
Kroodsma says he recently took a long bike trip, from the Atlantic Coast
through Virginia, Kentucky and Illinois. He says the accents and dialects of
both people and birds changed along the way.
Script for Tuesday, May 10, 2005
