North American Birds Declining as Threats Mount

A Cerulean Warbler perched on a branch. Photograph by Glenn Bartley, Corbis

A Cerulean Warbler perched on a branch. Photograph by Glenn Bartley, Corbis

Throughout the year, birders look forward to changing seasons and avian scenes as they explore woods, grasslands, and wetlands: the spectacle of spring migration, the songs of breeding birds, the autumn southward flight of wintering species from northern nesting grounds.

Increasingly, though, both casual bird-watchers and ornithologists note a steady decline in numbers—not just of endangered species, but also of common birds not usually considered to be at risk. Study after study, survey after survey show a worrisome downward trend in populations.

A National Audubon Society report called Common Birds in Decline, for instance, shows that some widespread species generally thought to be secure have decreased in number as much as 80 percent since 1967, and the 19 others in the report have lost half their populations. The figures reflect an array of threats faced by birds throughout North America. (Read about the decline of European songbirds in National Geographic magazine.)

Migrants return from Central America to find that the brushy field where they nested the previous year is now a strip mall.

Millions of songbirds annually suffer bloody death in the claws of domestic cats. Millions more collide with city skyscrapers or communications towers, or fly into the glass windows of suburban houses.

And climate change could degrade or even eliminate habitats in ways that scientists have only recently begun to study and try to forecast.

Threats to songbirds occasionally make splashy headlines, as when Smithsonian scientists released a report in January indicating that free-ranging domestic cats kill far more birds than previously believed: between 1.4 and 3.7 billion birds annually in the lower 48 states.

The report, based on 21 studies of cats and birds in the United States and Europe, showed that cat predation may well be the greatest source of human-related bird mortality in the country. (Read “Why Novelist Jonathan Franzen Loves Birds.”)

The American Bird Conservancy addresses this often-contentious issue in its Cats Indoors campaign, aimed at convincing cat owners and local lawmakers that the environment is better off when cats are kept inside—as are cats themselves.

Though it brings the subject of bird conservation to a wide audience, the attention-grabbing news about cat predation reflects only one of many dangers looming for the continent’s bird life, some far more ominous.

Wind Farm Dangers

To conservationists, the gigantic blades of wind turbines represent double-edged swords.

Though numbers are subject to debate, one biologist estimated in 2009 that 440,000 birds were dying each year through impact with wind turbines. Whatever the figure, it’s bound to rise as more wind farms are constructed.

“We recognize and support the use of renewable energy to avoid climate change, which will impact everything,” says Gary Langham, vice president and chief scientist for the National Audubon Society. “Obviously we’re concerned about getting the siting done correctly, so there’s minimal chance of killing a condor or a golden eagle.”

The American Bird Conservancy and other groups support proposed regulations that would keep wind turbines away from migration routes, wetlands, wildlife refuges, and similar areas likely to be frequented by birds.

“In a way, this is the focal area at the moment because it’s the one that’s changing fastest, with the greatest increase in threat,” says conservancy vice president Michael Parr. “If we could get it right now, this will set the course for the next 30 years or so.”

In a related move, a coalition that includes conservationists, the Federal Communications Commission, and the Federal Aviation Administration has been studying the design of communications towers to try to reduce the estimated six-million-plus birds killed each year in collisions with the towers and their guy wires (the heavy cables that anchor the masts to the ground).

The most recent findings show that the steadily glowing red lights seem to confuse flying birds, causing them to crash into towers or to fly in circles until they drop from exhaustion. Replacing these lights with flashing strobe lights could cut bird mortality by as much as 75 percent without compromising aircraft safety.

Tower owners have questioned the accuracy of bird-death figures, and resist the expense of converting lights on existing structures. Nonetheless, conservation groups continue to push for safer tower lights, and the FAA is studying proposed new regulations.

Acre by Acre, a Losing Battle

Meanwhile, many ornithologists, while regretting bird deaths caused by cats and towers and supporting efforts to reduce them, see those and similar issues as distractions from a far more important problem.

“To me, the top three threats to birds overall are habitat loss, habitat loss, and habitat loss,” says Ken Rosenberg of the Cornell Lab of Ornithology. “We’re losing the battle acre by acre.”

Gary Langham of Audubon agrees. “Certainly to this point, loss of habitat is the number one problem,” he says. “In some cases, say in California, we have removed or converted up to 99 percent of riparian [streamside] habitat and 95 percent of wetlands. Those losses have huge impacts on birds.”

Several reports titled State of the Birds, issued jointly by the U.S. Fish and Wildlife Service and conservation groups since 2009, have tracked a broad downward trend for most natural bird habitats.

Grassland birds, for example, have declined about 40 percent in the past 40 years, reflecting the continuing loss and degradation of native prairie through expansion of cropland, overgrazing, and invasion by alien vegetation.

Of the more than 300 million acres of grasslands and pastures across the United States, only about 13 percent is publicly owned. As a result, conservation of such habitats depends largely on incentives to private landowners, including the federal Conservation Reserve Program (CRP), which pays farmers to take land out of agricultural production and convert it to environmentally valuable uses.

“The biggest factor in agricultural systems is changing commodity prices,” Cornell’s Rosenberg says. “With this big push to raise corn for ethanol production, just since 2008 we’ve lost 23 million acres that were in CRP and other farm-bill programs and have been converted back to crop production.

“So you could think of it this way: While we’re arguing about wind towers and all these other issues, we’ve lost 23 million acres of habitat. That’s the kind of really big thing that can have a major effect on bird populations.”

Just the Right Habitat

Habitat loss doesn’t necessarily mean acts as overt as turning forests into subdivisions or prairies into cornfields. For years, ornithologists have been worried about the cerulean warbler, a small blue-and-white bird of the eastern woodlands. Studies have shown a population decline for the species in recent decades of 50 to nearly 80 percent in some areas.

Biologists long thought that ceruleans needed mature deciduous forest, and were puzzled when the birds didn’t breed in what seemed like good habitat.

But thanks to newer research, they now know that ceruleans need broken mature forest, with gaps in the canopy—a condition not present in even-aged woodland created by modern forestry practices. Modify a mature forest to create gaps, and ceruleans will return.

Such results are good news for a threatened species, but it’s only one part of the puzzle that must be complete if the bird’s future is to be secured.

The cerulean warbler is classified as a neotropical migrant, one of dozens of birds that nest in North America but spend the winter in the tropics. They need habitats that provide food and shelter year-round, not just on North American breeding grounds.

But southern shelter is harder to come by as development degrades the environment in areas from Mexico and the Caribbean to Amazonia. The cerulean warbler spends winter on the slopes of South America’s Andes, at the same elevation where coca is grown to supply cocaine for illegal drug markets in the United States and Europe.

Forest loss for coca cultivation (and possibly spraying of herbicide in antidrug operations) may be harming cerulean populations nearly as much as changes to their habitats in North America.

Even if habitat isn’t destroyed, it can still be “lost” to birds in other ways. The piping plover, a small brown-and-white shorebird, nests on the same seaside beaches, lakeshores, and river sandbars that humans use for swimming, picnicking, and driving all-terrain vehicles.

Tires crush nests; dogs and raccoons eat plovers; picnickers cause breeding birds to abandon their eggs; dams on rivers change natural water flow and destroy nesting sites.

The population of piping plovers dropped to fewer than 3,000 breeding pairs in 2001. Recovery efforts have been under way for decades, including temporarily fencing off nesting beaches during breeding season and controlling predators.

Results have been mixed, with plovers in a few regions doing well while others barely hold their own. Measures to protect piping plovers have angered residents of towns such as Seabrook, New Hampshire, and Plymouth, Massachusetts, who see beach closures as violating their rights to use public recreation areas.

“Most Serious Threat This Century”

It’s easy to see the sudden loss of habitat when, say, a marsh is drained. The effects of climate change, by comparison, move in extreme slow motion. Yet scientists say the results will be far more profound.

The Bicknell’s thrush is a rare bird found in the United States only in high-elevation spruce-fir forests on a few mountaintops in the Northeast. In Canada, it breeds in similar habitat at lower elevations.

The great majority of these brown, robin-sized birds winter on the Caribbean island of Hispaniola. Biologists worry about the future of this vulnerable species, as it faces threats at both ends of its migratory journey.

If global temperatures continue to rise, spruce-fir forest could disappear from peaks in the United States, displaced by hardwood forest rising along mountain slopes. That would mean the end of Bicknell’s thrush as a breeding species in this country. (It could take longer for the species to be seriously affected in Canada.)

More threatening, however, is the condition of the wintering range on Hispaniola.

Decades of intensive logging and clearing for agriculture have destroyed nearly all natural forest in the desperately poor country of Haiti, which comprises the western third of the island. In the Dominican Republic, which occupies the rest, illegal logging is eating away at a national park that’s one of the most important winter refuges for the Bicknell’s thrush.

The species could well disappear even before climate change eliminates its nesting habitat.

But climate change will affect birds in multiple ways, some of them impossible to predict. One small example: Gray jays, the bold “camp robbers” of boreal forests, depend for much of their winter food on nuts and other items they cache during fall, when food is abundant. If temperatures rise, much of that food could rot by the time the jays need it, instead of being safely stored in a natural freezer.

The National Wildlife Federation recently issued a report calling climate change “the most serious threat this century facing America’s migratory birds.”

Changing precipitation patterns in the midwestern “prairie pothole” region, the NWF says, could cause the loss of significant breeding habitat for ducks, including mallards and pintails.

Another potential climate change victim: the shorebird called red knot, which depends on horseshoe crab eggs in Delaware Bay to provide energy on its northward spring migration. Changing climate, the report says, could disrupt the timing of horseshoe crab egg-laying and the red knot’s stopover in the bay.

In one significant way, North American birds are better off than their relatives across the Atlantic. As Jonathan Franzen reports in the July issue of National Geographic, hunting takes a significant toll on a wide array of birds in Europe and northern Africa—not just waterfowl and other traditional game species, but also songbirds, hawks, and shorebirds, killed by the millions in nearly unregulated slaughter.

Thanks to better (and better-enforced) conservation laws and different hunting traditions, North American nongame birds don’t suffer the same year-round ordeal of guns and traps; our migratory species aren’t forced to run a gantlet of indiscriminate shooters as they travel to and from their breeding and wintering grounds.

The threats they encounter here, though, are varied and—whether immediate or long-term—just as deadly.

Source: news.nationalgeographic.com

The piping plover that won’t give up

Piping plovers are related to killdeers, but they’re smaller — a little more than seven inches (18 centimetres) long, with long legs for wading. Think of an over-sized sparrow on long legs.Photograph by: Handout photo , U.S. Fish and Wildlife Service

Piping plovers are related to killdeers, but they’re smaller — a little more than seven inches (18 centimetres) long, with long legs for wading. Think of an over-sized sparrow on long legs.
Photograph by: Handout photo , U.S. Fish and Wildlife Service

OTTAWA — Decades after it appeared to have disappeared from Ontario, the tough little piping plover — a tiny shorebird that nests on open beaches — keeps defying the odds and returning.

In 2007, a single pair nested on the Canadian side of Lake Huron, the first time in 30 years that the little birds had nested on the Canadian side of the Great Lakes.

By 2009 there were six known nesting pairs along the lake, including Georgian Bay, plus a father with four fledglings on Manitoulin Island.

There are larger populations, too, on the Prairies — about 1,000 birds — and in the Atlantic provinces, with a few hundred. But Ontario is their most precarious territory.

Now Environment Canada has published an action plan to help the birds survive in Ontario in the face of their chief competition: Vacationing humans who love the same beaches that plovers do.

Their shaky return to the Great Lakes “is a miniature success story,” says veteran birder and the Citizen’s new Birds columnist Bruce DiLabio, who warns against being too optimistic about the plovers’ future in Ontario.

Plovers are related to killdeers, but they’re smaller — a little more than seven inches (18 centimetres) long, with long legs for wading. Think of an over-sized sparrow on long legs.

A century ago they nested in Presqu’ile Park and Prince Edward County, DiLabio notes. But nesting in the open leaves them vulnerable both to humans and to other threats — storms and gulls that raid nests. The gull population in Ontario exploded in the late 1900s.

Plovers migrate to southeastern U.S. states for the winter.

The birds don’t have a high success rate at raising young and migrating, even when they do nest.

“There’s a lot of pressure on them,” DiLabio said. “That’s why they set up these fenced-in areas, to protect them as best they can. They have a major battle.”

Today’s Ontario birds appear to have moved up from Michigan.

“All it takes (to re-establish a population) is a couple of pairs, and they try,” he said.

Adults may live five to 10 years, “so if they can get back to these locations, they’ll keep trying and trying. They may not be successful.”

The action plan calls for protection of known nesting areas to keep away people and dogs and leave the natural vegetation in place.

The problem is that even coming too close to the nest can spook the birds, and they like to have a full kilometre of undisturbed beach.

The entire North American population is in the range of 6,000 birds, with modest growth in the Prairies and Atlantic regions.

source : ottawacitizen.com

 

Death toll climbs as giant birds are felled by tiny lead fragments

One of America’s most visible endangered species is falling victim to hunters, but not in the way you might expect.

The severe death toll in the last few months has taken out almost 10 percent of the Utah-Arizona condor population.

The severe death toll in the last few months has taken out almost 10 percent of the Utah-Arizona condor population.

Since early December, seven California condors have died near the Utah-Arizona border, possibly from eating fragments of lead bullets in the tissue of deer and elk left in the wild by hunters gutting their trophies.

“It’s been really bad lately,” said Chris Parish, who directs the condor recovery program for The Peregrine Fund. “This is probably one of the worst periods that we’ve experienced.”

Last weekend, Parish received a lab report confirming what he suspected: One of the dead birds found recently in Zion National Park died from the effects of lead poisoning.

Two other recent condor deaths were conclusively linked to lead ingestion. The cause of death has not been determined for the other four.

The carrion-eating birds resemble vultures — but on a larger scale. A typical adult has a wingspan of 9 ½ feet. Tourists often see the giant birds soaring around clifftops or swooping close to highways and bridges in the rugged topography of southern Utah and northern Arizona.

The fact that any California condors are still alive today is a big success story. Three decades ago, the wild population of the giant scavengers dwindled to just 22 birds.

“This bird’s been around since the last of the ice age and it’s still here,” Parish said. “And it almost went by the wayside.”

In a controversial rescue in the 1980s, all 22 surviving wild condors were rounded up and placed in a captive-breeding program. Releases back into the wild began in the 1990s in California and along the Utah-Arizona border.

In spite of that high-profile rescue operation, North America’s largest land-based bird species is still battling for survival.

The severe death toll in the last few months has taken out almost 10 percent of the Utah-Arizona condor population. The population dropped from 80 condors to 73. A separate population of the birds lives in California.

Since releases began in 1996, 84 of the Utah-Arizona birds have died or disappeared — about half of those that were released or hatched in the wild. Scientists were able to determine the cause of death in 52 of the 84 birds. Exactly half, 26, died from lead poisoning.

Experts suspect the toll from lead may be significantly higher. Blood tests and X-rays of the birds regularly confirm the presence of lead, especially in weeks and months following the hunting seasons for deer and elk.

Parish said the birds consume lead fragments when they eat tissues of deer and elk that have been shot by hunters. The hunter typically takes the deer or elk meat home and leaves behind the entrails. Condors love to eat the so-called gut-piles, and, according to Parish, testing has shown they’re often laced with lead fragments.

Utah wildlife officials are formulating incentives so hunters will turn in deer entrails instead of leaving them to be dined on by condors. Both states are also educating hunters and giving out coupons for free non-lead bullets.

“We’re not saying get rid of all the lead,” Parish said. “We’re saying, for the lead that you’re going to leave in the field in the remains of a carcass or a varmint species, just use non-lead.”

The lead-poisoning theory was not contested by a spokesman for the Utah Shooting Sports Council. It also was not challenged by pro-hunting activist Don Peay, founder of Sportsmen for Fish and Wildlife. Peay suggested, though, that hunters might actually be helping the condors survive. He said even if 10 percent die from lead poisoning, the species as a whole may benefit from eating deer and elk entrails that hunters leave behind.

sources : By Deseret News

Bird food recall: Parakeet and canary food affected due to possible salmonella

The U.S. Food and Drug Administration (FDA) has announced a bird food recall on Feb. 27. United Pet Group, Inc. has recalled four bird food products due to possible contamination with salmonella.

recall bird foodOne of the pet food company’s raw ingredient suppliers – Specialty Commodities, Inc. – had recalled a batch of dried parsley flakes.

The human-grade herb was distributed on May 30, 2012 and Aug. 29, 2012 to United Pet Group to be used into their finished bird food brands. Continue reading

New Study Finds Pesticides Leading Cause Of Grassland Bird Declines

A new study led by a preeminent Canadian toxicologist identifies acutely toxic pesticides as the most likely leading cause of the widespread decline in grassland bird numbers in the United States, a finding that challenges the widely-held assumption that loss of habitat is the primary cause of those population declines.

The scientific assessment, which looked at data over a 23-year period – from 1980 to 2003 – was published on Feb. 20, in PLOS One, an online peer-reviewed scientific journal. The study was conducted by Dr. Pierre Mineau, recently retired from Environment Canada, and Mélanie Whiteside of Health Canada.

The study looked at five potential causes of grassland bird declines besides lethal pesticide risk: change in cropped pasture such as hay or alfalfa production, farming intensity or the proportion of agricultural land that is actively cropped, herbicide use, overall insecticide use, and change in permanent pasture and rangeland.

“What this study suggests is that we need to start paying a lot more attention to the use of pesticides if we want to reverse, halt or simply slow the very significant downward trend in grassland bird populations. Our study put the spotlight on acutely toxic insecticides used in our cropland starting after the Second World War and persisting to this day – albeit at a lower level. The data suggest that loss of birds in agricultural fields is more than an unfortunate consequence of pest control; it may drive bird populations to local extinction,” Dr. Mineau said.

Many grassland bird species have undergone range contractions or population declines in recent decades. In fact, analyses of North American birds indicate that these birds are declining faster than birds from other biomes.

Habitat protection has long been considered a central pillar in efforts to stem the decline of grassland bird species, such as the Vesper Sparrow, the Ring-necked Pheasant, and the Horned Lark.

“We are still concerned about loss of habitat in agriculture, range management, and urban development,” said Cynthia Palmer, manager of the Pesticides Program at American Bird Conservancy, a leading U.S. bird conservation organization. “This study by no means diminishes the importance of habitat fragmentation and degradation. But it suggests that we also need to rein in the use of lethal pesticides in agriculture, and that we need to be especially careful about any new pesticides we introduce into these ecosystems such as the neonicotinoid insecticides. It reminds us that the poisonings of birds and other wildlife chronicled a half century ago by famed biologist and author Rachel Carson are by no means a thing of the past.”

The researchers focused on the extent to which lethal pesticides, such as organophosphate and carbamate insecticides, are responsible for the decline in grassland bird populations. The study found that lethal pesticides were nearly four times more likely to be associated with population declines than the next most likely contributor, changes in cropped pasture – an important component of habitat loss associated with agricultural lands.

The publication says that “…..large quantities of products of very high toxicity to birds have been used for decades despite evidence that poisonings were frequent even when products were applied according to label directions.”

Horned Lark and chicks

Horned Lark and chicks
– photo by Middleton Evans

The authors argue that only a small proportion of total cropland needs to be treated with a dangerous pesticide to affect overall bird population trends. The production of alfalfa stands out for its strikingly high chemical load, constituting the third highest lethal risk of any crop based on toxic insecticide use. Pesticide drift from croplands is also affecting birds that favor the adjoining grasslands. Continue reading

Bird watchers see barred owl increase this year

barred owls

Barred owls

While it isn’t mild now, last year’s winter is keeping owl rehabilitators in Vermont busy this year.

Last year was a good one for barred owls. And now, bird watchers are seeing more out in the wild — and more coming in injured from accidents with people.

At Outreach for Earth Stewardship in Shelburne, they’re rehabilitating eight owls this winter alone. Last year at this time, they only had one. Experts say the weather is to blame. Continue reading