Washington, Aug 6 : A new study from Rutgers University has revealed that exposure to a changed acoustic and social environment has a significant impact on the sounds produced by songbirds.
Songbirds learn to sing by hearing and imitating adults. Their brain contains an area similar to the mammalian auditory cortex (the NCM) that is specialized to discriminate and remember the songs of other birds of the same species.
During the study, adult zebra finches were moved to a canary colony, and adult canaries were moved to a zebra finch colony.
These birds experienced a novel environment because canaries and zebra finches produce learned species-typical vocalizations that differ in their acoustic components.
Other birds of each species remained in their home colony and still others were placed in individual isolation.
After nine days, the tuning width was assessed in the brains of these songbirds. The team found that the tuning width significantly differed from birds that remained at home. In both the species experiencing life in a foreign colony, the tuning became narrower (i.e. more selective).
In canaries, which can learn new song elements in adulthood, these effects were also influenced by season, and may reflect the role of vocal imitation in the seasonal breeding behaviour of this species. Isolation had the opposite effect: the tuning became wider (i.e. less selective).
The songbirds' tuning coarsened in the impoverished, monotonous environment provided by being housed in isolation.
In simple words, when a bird is exposed to a new acoustic and social environment, basic auditory properties in its brain change to become more finely tuned.
In human terms, a when a person travels to a foreign country where an unfamiliar language is spoken. The individual has to pay close attention and gradually begins to make out the words in the speech stream
This process of "tuning in" to the new sound and social environment may involve increased sensitivity to fine acoustic details and may produce measurable tuning changes such as those observed at the neural level in these songbirds.
The new study is published in August 6 in the online, open-access journal PLoS ONE.