Male zebra finches who grow up without fathers aren't doomed to a song-less adulthood; they can still learn their dad's tune by mimicking their brothers, researchers say.
Songbirds have a knack for vocal learning that's rare in the animal kingdom. The birds' songs are not innate; rather, they pass down melodies from one generation to the next, somewhat like human parents who teach their children to speak, but on a much shorter timeframe.
Male zebra finches start memorizing their dad's song as early as 17 days old. They practice and perfect it by imitating their dads over the next several weeks. By the time they reach adulthood, at roughly 100 days old, the birdsong is set in stone and the finches use it in an attempt to woo mates.
But just as human children can also pick up language quirks from their peers, zebra finches can pick up songs by listening to their siblings when an adult isn't around, the new study finds.
Researchers from the Max Planck Institute for Ornithology in Seewiesen, Germany, studied pairs of juvenile zebra finches that were separated from their fathers at 14 days old, before song-learning began.
When the birds were a month old, one of the brothers was sent to spend a week with the father and was exposed to the dad's signature song. The other young bird, meanwhile, was kept alone and never directly heard the paternal song.
The brothers were reunited and when they hit adulthood, their songs were recorded. Interestingly, the siblings' songs were more alike than the songs of the brother and father who spent a week together, the study found.
This suggests that a peer can serve as an effective substitute song model in the absence of a father for zebra finches. The researchers suspect learning from a peer could be a common strategy in birdsong acquisition.
Their findings were detailed in the journal Biology Letters on Wednesday (June 12).