Canary in a coal mine: Survey captures global picture of air pollution's effects on birds

Canary in a coal mine: Survey captures global picture of air pollution's effects on birds
A sparrow perches on a branch in Curtis Prairie at the UW Arboretum. The efficiency of birds’ respiratory systems is thought to make them more vulnerable to pollutants in the air. Credit: Jeff Miller

Famously, the use of caged birds to alert miners to the invisible dangers of gases such as carbon monoxide gave rise to the cautionary metaphor "canary in a coal mine."

But other than the fact that exposure to toxic gases in a confined space kills caged before affecting humans—providing a timely warning to miners—what do we know about the effects of air on birds?

Not as much as you'd think, according to researchers from the University of Wisconsin-Madison.

"We know a lot about air pollution's effects on human health, and we know a lot about the impacts of air pollution across ecosystems," explains Tracey Holloway, a professor in UW-Madison's Nelson Institute for Environmental Studies. "We were surprised to discover how little we know about how air pollution affects birds."

Writing Aug. 11 in the journal Environmental Research Letters, Holloway, an expert on , and her former graduate student Olivia Sanderfoot, sort through nearly 70 years of the scientific literature to assess the state of knowledge of how air pollution directly affects the health, well-being, reproductive success and diversity of birds. This work is part of Sanderfoot's ongoing National Science Foundation Graduate Research Fellowship.

According to the Wisconsin team's survey of the literature, only two field studies since 1950 have looked at any aspect of the health and ecological well-being of wild bird populations in the United States. Globally, there are only a handful of studies that assess the impact of direct exposure to air pollutants on bird health. Those encompass studies of just a few dozen bird species of the roughly 10,000 or so species of birds known worldwide.

Part of the problem, says Sanderfoot, are the many variables in play. Not only are studies of wild bird communities difficult to implement, but factors such as types and levels of air pollution, dynamic atmospheric conditions, species-specific responses, and the difficulty of teasing out direct versus indirect effects of air pollution can confound even the most basic efforts to assess how birds fare when exposed to chemicals in the air.

"There is a lot of work to be done in this area," says Sanderfoot. "Air quality is an ever-changing problem across the globe. There's a need to look at different types of air pollution and different species all over the world. We have a huge lack of understanding of the levels of pollution birds are exposed to."

Gaps in our understanding, according to the new study, include air pollution's effects on the avian respiratory system; toxic effects on birds, including elevated stress levels and immunosuppression; behavioral changes; and effects on and demographics, such as changes in population density, species diversity and community composition.

Holloway, who leads the NASA Health and Air Quality Applied Sciences Team (a multi-institutional team of researchers that serves as a nexus for analyzing environmental data from a constellation of Earth-observing satellites), notes that studying the effects of air pollution on humans is comparatively easier to assess as hospital records and mortality data are readily available to scientists. Air pollution, in fact, is one of the leading and most direct environmental threats to human health, she says.

Something that makes birds potentially more vulnerable to atmospheric contaminants is the efficiency of the avian respiratory system.

"Birds breathe unidirectionally," notes Sanderfoot. "They definitely breathe more efficiently than humans, and it has been hypothesized that because their respiratory system is so much more efficient than ours, they are going to more readily pick up ."

The study is a springboard for new research, Sanderfoot and Holloway argue, and may be especially important given birds' role as sentinel species in the environment.

"When you talk to bird ecologists, air pollution is not necessarily perceived as a high-level issue," Holloway says. "Things like climate and landscape changes are at the top of their list in terms of population densities, species diversity, ecological stress. But we know that air pollution is a major risk to , and from our study we see pretty clearly that there is an impact on birds, too."

Explore further

Study measures air pollution increase attributable to air conditioning

More information: Olivia V Sanderfoot et al. Air pollution impacts on avian species via inhalation exposure and associated outcomes, Environmental Research Letters (2017). DOI: 10.1088/1748-9326/aa8051
Journal information: Environmental Research Letters

Citation: Canary in a coal mine: Survey captures global picture of air pollution's effects on birds (2017, August 11) retrieved 19 July 2019 from
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Aug 13, 2017
Air pollution? I'm so old I remember London Fogs and not being able to see the San Gabriels from downtown LA except for a few days a year. Now there are no more London Fogs and you can see the San Gabriels all but a few days a year.

Why keep harping on a job well done? Ah, yes, to acquire continued research funding from "those" who would have greater control of the means of production. I see.

Aug 13, 2017
Air pollution?

There's a difference between 'has gotten better' and 'is good'.
(and there's plenty of places in the world where the pollution situation hasn't gotten better)

Aug 13, 2017
Yes but shootist aka antigoracle/waterprophet sockpuppet lives in his own cubicle of space, outside that territory it's the real and big world where there is Real climate change happening due to Human Induced Fossil Fuel Pollution.

Aug 13, 2017
Air quality is vastly better than years ago (in the West, anyway) and there are far more birds than people. Stop worrying about them.

Aug 13, 2017
Air quality is vastly better than years ago (in the West, anyway) and there are far more birds than people. Stop worrying about them.
apparently you entirely missed the implication of the statement "Canary in a coal mine"

perhaps this will help: http://www.wisege...mine.htm


Aug 14, 2017
These near worthless monstrosities are more of a threat to birds than the air that they breath.

Birds killed by Wind turbines
The most recent number, published by analyst K. Shawn Smallwood in the March 2013 issue of the Wildlife Society Bulletin, is the highest to date.
He estimates that in 2012 turbines across the United States killed 573,000 birds, including 83,000 raptors. The number of bats killed, he reports, was even higher: 888,000.
His research was published just as the U.S. Department of the Interior and its agencies issued or were considering permits for wind-power companies to kill iconic and, in some cases, endangered bird species:
• And in late May, the Bureau of Land Management and Fish and Wildlife said they would grant, for the first time, a wind farm the ability to kill an endangered California Condor without danger of prosecution.

Aug 19, 2017
@jd swallowed the political rhetoric and is brain dead
Birds killed by Wind turbines
how many were killed by cars?
how about cats?

quit spreading irrelevant gish gallop bullsh*t to every climate article

you still haven't answered my request for refute of the scientific studies presented to you about CO2 plant food, let alone anything else

you posted lots of opinion, and articles about your belief, but not one single study that refuted that first part of my list on 18 aug

because you're a liar and illiterate spreading FUD

the only reason you're now posting as j doug is because your jdswallows sock was banhammered for the exact same bullsh*t tactics you're doing above

you're a lying TROLL idiot

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