does bad air quality affect birds

Harjavalta, Finland has been a smelting town since the 1930s, with most of the local economy built around metal production. It’s also a favorite summer breeding spot for Pied Flycatchers. But nearly three decades ago, scientists noticed that the visiting birds weren’t having as many chicks as usual. They traced the culprit back to the towns sole copper smelter: Sulfur oxide and heavy-metal particulates from the factory were wreaking havoc on the female flycatchers’ metabolisms, causing them to produce thin-shelled eggs that wouldn’t hatch. Around the same time, a different team of scientists discovered smelter workers had higher incidences of respiratory and stomach cancers.

Both birds and people were harmed by the noxious mix of pollutants in the air—but birds showed symptoms years earlier. Today, the Harjavalta copper smelter has cut toxic emissions by nearly 99 percent. Working conditions are much safer, and the Pied Flycatcher population has slowly rebounded as well.

The events in Harjavalta, among others, shows how birds can be sentinels in hazardous situations. And yet they’re underused and understudied, especially when it comes to air pollution, Olivia Sanderfoot, an environmental scientist at the University of Washington, says. Sanderfoot spent her last year at the University of Wisconsin-Madison (UW-M) compiling more than 90 papers that date back to the 1950s. Her findings, which outline the most common impacts of air pollution on birds and gaps in current research, were recently published in Environmental Research Letters.

Sanderfoot’s work confirmed her initial concerns. “It turns out that we don’t know much about how air pollution affects birds after all,” she says. While digging through the literature, she found thousands of studies that bypassed birds and focused solely on human health. There’s a reason for that: In 2016, the World Health Organization estimated 3 million people die annually from air pollution-related illnesses. But no one has ever quantified avian mortality in the same way.

Before diving into the numbers, however, Sanderfoot had to answer another question: Why are birds more vulnerable to air contamination? To do so, she had to revisit early lessons in avian anatomy. Unlike mammals, birds inhale oxygen, exchange it for carbon dioxide, and exhale the byproducts all in one breath; they don’t have to contract or expand their lungs repeatedly. The unique technique allows them to breathe and oxygenate at a rapid rate, which is optimal for flight. But Sanderfoot also contends that the constant air flow might bring in a variety of nasty particles that lead to health issues.

Indeed, respiratory illness was the most frequent problem Sanderfoot found in her review, followed by increased stress levels, poor immune systems, reduced reproductive success, population declines, and more. The studies analyzed a few dozen species from all over the world (though most were concentrated in Europe). While there was clear historical evidence of air pollution being detrimental to birds, there were still major gaps in connecting avian and human health.

“We don’t have enough evidence on birds dealing with the top-priority chemicals that hurt humans,” says Tracey Holloway, a professor of atmospheric and oceanic sciences at UW-M and coauthor of the review. Surface-level ozone and particulate matter (PM) wreak havoc on human respiratory systems and probably take out just as many birds lives each year, she notes. More avian research on these pollutants would help scientists get a better idea of the global state of birds—something that Holloway and Sanderfoot are all for.

But showing causation is a feat in itself. Birds and air particles are both changing mediums: Neither stays in place for very long. This makes it difficult to pinpoint which chemicals hurt birds in the long term. In the case of the flycatchers, the scientists already knew where they bred each year and what pollutants spewed out of the smelter. Without establishing those patterns, it’s nearly impossible to know where birds might pick up specific particles.

One way to go about it is to hone in on the most polluted sites they spend time in, which are typically cities, industrial sites, and developing nations. “The health of migratory birds is only as good as the worst place they spent time during their full annual cycle,” David Mehlman, director of the Migratory Bird Program at the Nature Conservancy, says. Another option is to incorporate better technology to understand what exactly is wafting about in the air. Sanderfoot and Holloway both recommend ramping up field monitoring, data collection via satellites, and computer modeling to track global air pollution and then map it against bird occurrences pulled from ornithological surveys. Field monitoring measures ozone and PM levels, satellites read carbon monoxide and nitrogen dioxide concentrations near the Earth’s surface, and computer models compare the past, present, and future in air-quality trends.

Ultimately, these holistic methods can inform conservationists and lawmakers to produce policies that protect people and wildlife. In a way, we’ve already seen how research on people breathing toxic air brought about change in the United States, Rob McDonald, lead scientist for the Nature Conservancy’s Global Cities Program, says. He points to the Environmental Protection Agency’s Clean Air Act as an American success story. “Our air quality is much better than it once was,” McDonald explains. “Now nations like China and India are taking some action and informing the public about clean air.”

Although air pollution is a global concern, Sanderfoot is picking up the local fight, too. As an educator with the Madison Audubon Society this past spring and summer, she visited community centers to teach kids how to curb air pollution by driving less, planting more natural habitat, and cutting back on energy use—all to save birds. A little work can go a long way, but above all else, she urged the students to find hope in every feathered creature they saw. “Because when birds flourish,” Sanderfoot says, “we can all breathe easier.”

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Ground-level ozone (O3) and nitrogen oxides (NOx), two of the most common air pollutants in California, are powerful oxidants that can cause direct, irreversible damage to birds’ lungs. Long-term exposure can lead to inflammation, ruptured blood vessels, and lung failure.

According to Audubon science, two-thirds of North American birds could go extinct due to climate change.

A study that looked broadly at the impacts of air pollution on biodiversity across the eastern United States found that the accumulation of nitrogen oxides (NOx) and sulfur oxides (SOx) causes soil and water to become more acidic. Soil and water acidification may reduce the abundance or the nutritional value of birds’ food sources. In some areas, this means lower calcium availability in the environment. Since calcium is a necessary component of eggshells, less calcium means smaller clutch sizes, according to a study in the eastern United States. Soil acidification has been shown to cause die-off of ponderosa pine roots in the San Bernardino Mountains.

A significant number of the emissions responsible for climate change pose an immediate health risk to avian populations.

There have been hints over the years about how air pollution affects birds, but we’ve all heard about how it can endanger human health.

Sanderfoot’s work confirmed her initial concerns. “It turns out that we don’t know much about how air pollution affects birds after all,” she says. While digging through the literature, she found thousands of studies that bypassed birds and focused solely on human health. There’s a reason for that: In 2016, the World Health Organization estimated 3 million people die annually from air pollution-related illnesses. But no one has ever quantified avian mortality in the same way.

Among other incidents, the ones in Harjavalta demonstrate how birds can serve as sentinels in dangerous circumstances. However, Olivia Sanderfoot, an environmental scientist at the University of Washington, claims that they are underutilized and underresearched, particularly in regards to air pollution. (2006) During her final year at the University of Wisconsin-Madison (UW-M), Sanderfoot compiled over ninety papers, some of which go all the way back to the 1950s. Her findings were recently published in Environmental Research Letters and describe the most common effects of air pollution on birds as well as research gaps.

But showing causation is a feat in itself. Both airborne particles and birds are ever-changing media; neither persists in one place for very long. This makes it challenging to identify the specific chemicals that harm birds over time. Regarding the flycatchers, the scientists were already aware of the annual breeding grounds and the contaminants that erupted from the smelter. Without identifying those patterns, it is practically hard to predict where birds may find particular particles.

In fact, Sanderfoot’s review revealed that respiratory illnesses were the most common issue, followed by high stress levels, weakened immune systems, poor reproductive outcomes, population declines, and more. A few dozen species from all over the world were examined in the studies (though the majority were found in Europe). Even though there was historical proof that air pollution hurts birds, there were still a lot of unanswered questions about the relationship between bird and human health.

Before diving into the numbers, however, Sanderfoot had to answer another question: Why are birds more vulnerable to air contamination? To do so, she had to revisit early lessons in avian anatomy. Unlike mammals, birds inhale oxygen, exchange it for carbon dioxide, and exhale the byproducts all in one breath; they don’t have to contract or expand their lungs repeatedly. The unique technique allows them to breathe and oxygenate at a rapid rate, which is optimal for flight. But Sanderfoot also contends that the constant air flow might bring in a variety of nasty particles that lead to health issues.

FAQ

What bird is most affected by pollution?

In the marine environment, seabirds are particularly vulnerable to oil pollution, especially species of auk, seaduck and diver that spend a lot of time on the surface where the oil forms a film.

Does poor air quality affect hummingbirds?

Because hummingbirds breathe many times more air per body weight than mice (which decrease their spontaneous wheel running activity with ozone exposure), they may also experience adverse effects from ozone.

How does bad air quality affect wildlife?

Air pollutants can poison wildlife through the disruption of endocrine function, organ injury, increased vulnerability to stresses and diseases, lower reproductive success, and possible death.

Does the smoke affect birds?

Smoke damages birds’ lungs and leaves them susceptible to respiratory infections, some of which can be fatal. Meanwhile, the fires themselves destroy critical areas of habitat that birds rely on for food and water.