White-throated sparrow. Photo: Scott M. Ramsay/Wilfrid Laurier University

Over 19 years, a once rare song sang by sparrows in western Canada has spread across North America, replacing a traditional song along the way, according to new research.

The big picture: Birdsongs, like human languages, have dialects that can evolve, and birds and humans learn their languages in similar ways and timeframes.

  • Studying birdsong might help scientists to understand how humans develop dialects, says Angelika Nelson, an ornithologist at the Landesbund für Vogelschutz in Bavaria, Germany, who studied white-throated sparrow song and wasn't involved in the study.

Birdsongs can change over time but those changes are typically limited to a region and its dialect. In the case of the white-throated sparrows of North America, their song changed across the continent.

  • The traditional three-note-ending song, which dominated the repertoire of sparrows west of the Rockies, was abandoned for one that ends in two notes. (The mnemonic is Oh my sweet, Can-a-da, Can-a-da, Can-a-da! for the three-note tune versus Oh my sweet, Can-a, Can-a, Cana-da!)
  • The song spread across North America and, as of 2019, only birds in the easternmost regions of the continent continue to sing the triplet-ending song.

"This would be like, if you were from Kentucky, and you move to Seattle, and everybody starts thinking, 'hey, this Kentucky accent sounds awesome.' And suddenly 10 years later, everybody in Seattle has a Kentucky accent," says Ken Otter, an ornithologist at the University of Northern British Columbia and an author of the study.

  • "It's completely at odds with the expected norm for how regional song variants would establish and solidify. Instead this is actually spreading."

What they did: Otter and his colleagues used 1,785 male white-throated sparrow, Zonotrichia albicolis, bird song recordings collected by citizen scientists to show the spread of the new song.

  • Birds migrate and spend the winter with birds from other regions and the researchers thought perhaps the younger birds were learning the new song from their seasonal friends and taking them back to their breeding grounds.
  • The team tracked the location of sparrows with backpack geolocators and found those from the west, where the song was first observed, were overwintering in the southern U.S. with birds from farther east, where the song was later observed.
  • "It took 9 years (2005–2014) for the song variant to go from approximately 1% to 22% of males adopting, but then only 3 years (2014–2017) to go from 22% to nearly 50%, suggesting that the cultural spread may be exponential once a critical number of males have begun adopting the new variant," the authors write in Current Biology.
  • "To our knowledge, this is an unprecedented rate of song-type transition in any species of birds."

The intrigue: It's unclear why the new song is preferable.

  • Males sing to defend territory, which allows them to attract a mate. At the same time, females use birdsong to assess a male's prospects as a mate.
  • The researchers think females may have a preference for novel songs — but not too novel.
  • What to watch: Evidence for that comes from another song that has emerged — and spread — in the west. (This one is a doublet too but the first note is modulated.)
  • "As of this year, it's completely replaced the traditional doublet. And so there was nothing super special about the doublet," says Otter. "It was just something different."

Go deeper

Neil Young blasts Trump for using his music at Mt. Rushmore

Neil Young in Sept. 2019 in East Troy, Wisconsin. Photo: Gary Miller/Getty Images

Neil Young spoke out against President Trump this weekend for using two of his songs at a Fourth of July celebration at Mount Rushmore.

Flashback: Young's management company had a similar grievance with Trump's 2016 presidential campaign, saying that the then-candidate was not allowed to use "Rockin' in the Free World" for his candidacy announcement in 2015.

30 mins ago - Health

Axios-Ipsos poll: Fear of voting

Data: Axios/Ipsos poll; Note: ±3.0% margin of error for the total sample; Chart: Andrew Witherspoon/Axios

Democrats are twice as likely as Republicans to worry about in-person voting — with nearly two in three seeing it as a large or moderate risk to their health — according to this week's installment of the Axios-Ipsos Coronavirus Index.

Why it matters: This could pose a significant disadvantage for Joe Biden and other Democratic candidates in November if the pattern holds — especially in states where high infection rates persist, or where there are significant hurdles to mail-in, absentee or early voting.

Trump: Coronavirus is "under control"

President Trump said in an interview with “Axios on HBO” that he thinks the coronavirus is as well-controlled in the U.S. as it can be, despite dramatic surges in new infections over the course of the summer and more than 150,000 American deaths.

  • “They are dying, that's true. And you have — it is what it is. But that doesn't mean we aren't doing everything we can. It's under control as much as you can control it. This is a horrible plague,” he told Axios' Jonathan Swan.