This video from the USA says about itself:
From the New York Times in the USA:
Sparrows Don’t Just Sing Same Old Song
JAN. 12, 2015
A sparrow’s song may sound simple, consisting of little more than whistles and trills. But to the sparrows, those few noises can take on vastly different meanings depending on small variations in context and repetition, researchers have found.
In humans, the ability to extract nearly endless meanings from a finite number of sounds, known as partial phonemic overlapping, was key to the development of language. To see whether sparrows shared this ability, researchers at Duke University recorded and analyzed the songs of more than 200 Pennsylvania swamp sparrows. They found that the sparrows’ whistles could be divided into three lengths: short, intermediate and long.
The researchers then played the sparrows two versions of the songs — the original and a slightly altered one. They found that replacing a single short whistle with an intermediate one, for example, could significantly alter a bird’s reaction, but only if it came at the right moment in the song.
“Identical sounds seemed to belong to a different category depending on the context,” said Robert F. Lachlan, a biologist now with Queen Mary University of London and the lead author of the study.
The findings, which were published in Proceedings of the National Academy of Sciences, are part of a larger effort to better understand how human language evolved. If even birds rely on phonemic overlapping to communicate, Dr. Lachlan said, it could indicate that such features “developed independently of higher aspects of language.”
By faithfully copying the most popular songs, swamp sparrows create time-honored song traditions that can be just as long-lasting as human traditions, finds a new study. The results show that creating traditions that pass the test of time doesn’t necessarily require exceptional smarts: here.