Every other Friday, the Outside/In team answers a listener question about the natural world. Ange emailed the team to ask:
“Do birds that are the same species have ‘accents’ if they live in different regions?”
“Yes, they absolutely do,” said Chris Sturdy, a psychologist who studies songbird communication and behavior and cognition at the University of Alberta in Canada. “But I fell into bird dialects by accident.”
About 10 years ago, Sturdy and a PhD student, Allison Hahn, were researching black-capped chickadees, looking for acoustic markers in birdsong to see if there was a difference between dominant and subordinate birds.
They ran recordings of chickadee “fee-bee” songs through an artificial neural network, a type of machine learning program.
They predicted the results would reveal clear groups of dominant and subordinate birds. Instead, when they looked at the data, it did not reflect their hypothesis. That was a bit discouraging at first.
“This is why I and others always tell their students to not be afraid of the data,” said Sturdy.
“Because we were actually open to it, after a bunch of head scratching, cursing, and all the rest … we figured it out, but it took a left turn into this idea of geography.”
The issue was: These chickadees had been recorded in very different parts of Canada, and their regional accents were messing up the data.
While it was known that other species of songbirds had regional dialects, like white-crowned sparrows and chaffinches in Scotland, people thought that chickadees sang the same song across the North American continent, except for a couple isolated populations.
So, Sturdy and Hahn rallied. They set off with a new focus: Studying two groups of birds around 1,500 miles apart or so.
It turns out that while the human ear couldn’t pick up the differences, other chickadees sure could.
“That's their livelihood. You know, they use songs for attracting a mate, defending a territory, communication – it’s highly biologically relevant,” said Sturdy.
One reason behind avian accents could be because songbirds learn their tunes a bit like the human game of “Telephone.”
“Even though birds will copy the song patterns from their models, usually their fathers or another male living nearby (at least in temperate North American species), there might be slight errors in the copying. Those errors are propagated through subsequent generations,” said Sturdy.
Submit your question about the natural world to the Outside/In team. You can record it as a voice memo on your smartphone and send it to outsidein@nhpr.org or call the hotline, 1-844-GO-OTTER. We also accept questions sent to Twitter or Instagram. We’re @OutsideInRadio in both places.
Editor's note: The original piece incorrectly stated the type of analysis conducted on recordings of chickadee songs. This audio for this article has been updated.
