How sparrows from B.C. spread a new song to the rest of North America
A team of biologists spent 14 years tracking how a group of birds from B.C. became song influencers, eventually changing how the white-throated sparrow warbles from the Rocky Mountains all the way to the border of Quebec.
“It hasn’t been reported on this kind of magnitude or scale before, and that’s why it was interesting project to do, to look at how quickly the song is actually spreading,” Ken Otter, a biology professor at the University of Northern B.C., told CTV News.
The original sparrow song included an introductory phrase, and then three notes at the end, something like, “Oh my sweet Canada Canada Canada,” Otter explained.
The new song has just two notes at the end, resulting in something more like, “Oh my sweet Cana Cana Cana.” (Watch the video to see a full interview with Otter, and to hear the two different types of birdsong.)
Otter and other researchers initially noticed the change in birdsong in 2005 in central B.C., and assumed it was contained to just one small population of white-throated sparrow.
“But in about 2010 to 2014, we realized the song seemed to be spreading eastward, so we’ve been enlisting people to help us track this and found that the song has spread right into Ontario and is bordering right around Quebec,” Otter explained.
Birdsong does change over time, Otter said, but typically a new song type doesn’t completely replace an older song. It’s also very unusual for it to happen so quickly.
The researchers tracked the migration patterns of the birds, and the song’s spread, by attaching geolocators to certain birds from Prince George, B.C. and tracking their migration to other parts of Canada and the United States.
“They have to learn their songs from adult tutors, and so what you would expect is that most of the birds would learn the song that’s common to their environment or their neighbourhood,” Otter said.
“And so when the new song type emerges, you’d expect it to peter out, but what’s happening is these birds seem to be adopting the new song type."
No one knows for sure why the birds changed their tune, but in a paper Otter and the research team published, they hypothesize that it could help the males attract female mates.
“Within white-throated sparrows, females prefer songs that include the terminal phrase over those that simply have the introductory notes, suggesting that females are attentive to the terminal portion of the song,” according to the researchers.
“But if female response to song variants wanes slightly over time… males may integrate novelty to maintain female interest.”
With files from CTV News.