Would you like to sing songs that your great-great-grandfather danced to? Apparently, these American swamp sparrows do! A new study published in the journal Nature Communications says that the swamp sparrows are so adept at mimicking the sounds of their elders, that little has changed in centuries.
Swamp Sparrows' cultural traditions
When these little American swamp sparrows sing, puffing out their feathered chest and lifting their head high, they look almost proud before letting long sputter of chirps. As it turns out, swamp sparrows have reason to take pride while singing. They have been singing those melodic tunes for more than 1,000 years, found a study.
Scientists from Duke University have found evidence that these birds preserve their cultural traditions on for generations much like humans.
Duke biologist Stephen Nowicki, who co-authored the study with a mathematician and a psychologist, said, "The song types I hear in the morning are the same song types that the earliest European settlers would have heard. When the first European invaders came over 500 years ago, they heard what I was hearing just a week ago."
Dr Robert Lachlan, the study's lead author and a biologist at Queen Mary University of London said, "If you go to a marsh in the northeast of the U.S. that has been relatively undisturbed, and you listen to the swamp sparrow songs there, the odds are that the commoner ones you hear are quite ancient traditions."
The baby sparrows learn to memorize tunes from their elders as early as first few weeks after leaving their nest. By the next spring, they will start singing several songs, before whittling their repertoire down to the three syllables they need to sing as adults.
As babies, even humans react to all languages, but we lose the syllables as we grow older and not use in our native language. "They have evolved a communication system for which culture plays a central role," said Dr Lachlan.
How did they find?
During 2008 and 2009, the researchers recorded 615 male birds over six North American populations and they recorded 160 different syllables from these birds.
Using acoustic analysis software they brought down the sound into notes. The findings revealed that these birds accurately learned their songs 98 percent of the time.
The researchers also compared the swamp sparrow songs of today with recordings from the 1970s. The findings conclude that the most popular type then is still the most popular type now.
Nowicki said, "It's like the telephone game when you tell someone a sentence and they tell someone something else, and 10 times later it's completely different. What's interesting is that a thousand times later, you still have the same syllable type in this population."
Conformist bias in wild animals
The study reveals that it is a clear example of conformist bias in species. "Swamp sparrows do not pick songs to learn at random. Instead, they appear to selectively choose the commoner song types that they hear to copy," Dr Lachlan said.
The swamp sparrows' songs serve two different functions. Only male birds sing songs to defend their territories during mating season and female sings tunes to choose their mates. The brain size of these sparrows are very small and do not show any signs of cognitive sophistication along the lines of primates or crows.
"Instead, the study suggests that simply learning accurately can generate some aspects of culture," said Dr Lachlan.
Are humans different?
The imminent question is whether we, humans, are different from these sparrows when it comes to imitation or inheritance of songs. The rhymes, for instance, remain the same across the world and children pick them up the same way even after centuries. So are the old sayings in languages or proverbs in many languages. It's all in genetics and genes hardly disappear from appearing in our progency.
