Chickadees prove noise pollution impact

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Photo: Dr. Steffi Lazerte

by EVAN MATTHEWS

A UNBC researcher has uncovered a link between Black-capped Chickadees and noise pollution created by humans in urban areas.

A former PhD student, Dr. Steffi Lazerte, was studying Black-capped Chickadees last year to see how they communicated in urban noise, specifically, to see if they could learn to better cope with it.

“We don’t often think of noise pollution as actually being pollution, but it is,” says Dr. Lazerte. “We have to be careful because we found that some birds can deal with our pollution, but they have to learn to adapt … birds that can’t learn might be in big trouble,” she says.

The idea for Lazerte’s study came from an animal communications course, she says. The professor had told her if you take down a big tree, the acoustics of a forest change, and she says ever since, the whole subject has been fascinating to her.

“A previous study had shown birds in noisy areas sang higher frequency songs than birds in quieter areas,” says Dr. Lazerte. “We knew their vocalization, or how they sang, changed depending on their environment.

“We wanted to know if they learned to change their frequency, and how quickly this change in their frequency would happen,” she says.

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Photo: Dr. Steffi Lazerte

The study, which was done in the Prince George, Quesnel, Kelowna and Vancouver areas, showed there was, in fact, a learning component involved.

Lazerte would play back noise to Chickadees familiar with noise, and the birds immediately shifted their pitch up, she says.

“If we went to quiet areas and played back noise to those Chickadees, they actually shifted down,” says Dr. Lazerte. “They went the opposite direction you’d expect, based on the idea of avoiding masking, so to avoid overlapping the frequencies.”

With all small songbirds, and many birds in general, Lazerte says males are usually the only birds that sing. Females can sing among some species, but they’re the exception.

How well a male sings, and how often they sing — there are different metrics for singing — shows off how awesome they are, Lazerte says, and it’s a way of defending territory because it broadcasts to all their neighbours, ‘this is my spot, and this is how good I am.’

Singing is also the best way for Black-capped Chickadees to attract a mate.

“Females can listen to a song, and they actually evaluate the quality of a male based on the song,” says Dr. Lazerte. “Bird song is actually funny, because it essentially boils down to, ‘hello ladies! And, piss off my branch.’”

If the males can’t be heard, they can’t defend their territory, Lazerte says, and if they can’t defend their territory, they don’t have a place to nest. A male can’t attract a female if he doesn’t have a nest, she says.

“If they can’t be heard, they don’t reproduce, and their reason for being is non-existent,” says Lazerte.

Some birds are less flexible than Chickadees and never change their tune, she says, while some birds never, ever, sing the same song twice.

“The Nightingale is really known for that,” says Lazerte.

While the Black-capped Chickadee has proven to be a resilient species to human noise pollution, Lazerte says it’s possible only the really bright species are able to learn.

The more humans learn about interfering with animals, Lazerte says, the more we can learn to avoid it.

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