Climate change spells avian trouble
“Martha” was the last known passenger pigeon in the world. She died at the Cincinnati Zoo in September 1914, age (believed) 29, having never managed to lay an egg.
On the centenary of her passing and the passenger pigeon’s extinction, Martha’s stuffed remains — subjected to peripatetic storage through the decades — have been returned to the Smithsonian Institution, star of a year-long anniversary exhibit titled Once There Were Billions.
Billions and billions and billions, the most abundant bird in North America — a quarter of the entire avian population — through to the late 19th century. In full soaring flock, their numbers could block out the sun.
A recorded instance in southern Ontario from 1866 described the phenomenon of an estimated 3.5 billion of them migrating overhead, the formation a mile wide and 300 miles long, taking 14 hours to pass. More Hitchockian was the feathery solar eclipse they caused above Columbus, Ohio, as terrified children ran indoors.
It was inconceivable that ectopistes migratorius would ever disappear from the face of the Earth. Yet within a mere 40 years they were wiped out, only three breeding flocks documented. Finally, just lonely Martha remained, named for First Lady Martha Washington.
The passenger pigeon had fallen victim to rampant overhunting, destruction of their nesting colonies and infectious disease. They couldn’t reproduce fast enough to keep pace with the killing — for sport and as a source of cheap meat. It was a massacre. But Martha didn’t die in vain. The breed’s vanishing triggered passage in the U.S. of the Migratory Bird Act (five years later, the Migratory Birds Convention Act in Canada) and helped spur a broad 20th-century conservation movement. And still, here we are, in eco-enlightened 2014, with the grim news that the impact of climate change on delicate biodiversities is likely to drastically disrupt the continent’s bird population. Half of North America’s approximately 650 species will be driven from their traditional habitats, forced into ever smaller feeding and breeding zones, severely compromising the continued existence of particularly threatened species: the trumpeter swan, the brown pelican, the three-toed woodpecker, the eastern whippoorwill, the cerulean warbler, the spotted owl, the piping plover, the yellow-billed magpie, the northern shoveller, the rufous hummingbird, the osprey, the common loon. And more. Dozens of species could become extinct over the next 65 years, as projected in a comprehensive, alarming prospectus released this week by the National Audubon Society. Using data collected over three decades by “citizen-scientist observations” in the U.S. and Canada, and the North American Breeding Bird Survey, the Society has produced “climatic suitability” abstracts and maps encompassing factors such as temperatures, precipitation and gashouse emission scenarios. The primary finding: “Of the 588 North American bird species Audubon studied, more than half are likely to be in trouble. Our models indicate that 314 species will lose more than 50 per cent of their current climatic range by 2080.” Further: “Of the 314 species at risk from global warming, 126 . . . are classified as climate endangered. These birds are projected to lose more than 50 per cent of their current ranged by 2050.” By that mid-century mark, the report continues, the most threatened species mentioned above will no longer be able to live and breed in more than 90 per cent of their present territory. Imagine cottage country without the loon because the lakes are too warm. Imagine Don River ravine without the beautiful bird song of the wood thrush. Imagine British Columbia without the sandpiper. Imagine Maryland without the Baltimore oriole, found some day only on a baseball player’s cap. “It’s already happening to a certain extent with the loons,” says Ted Cheskey, senior manager of bird conservation with Nature Canada. “They’re not where they were 50, 60 years ago. They’re going to shift their range north. It’s likely we will lose loons (in southern Ontario) unless we turn this around.” He continues: “We always try to associate birds as indicators of broader environmental conditions and other biodiversities. They’re sort of like the sentinels, the canary in the coal mine.” Canada compiled a similar census of bird populations a couple of years ago. It identified three groups of birds that are “in very big trouble,” says Cheskey: grassland dependent species such as the meadowlark and bobolink; aerial insectivores that catch food on the fly such as swallows and nighthawks; and shore birds such as plovers, most especially the 45 or so species that migrate up to 30,000 kilometres a year from the Arctic to the South American coast. “They depend on a whole network of stopover sites,” explains Cheskey. But those are shrinking on the ground. A Nature Canada program has designated 600 such sites in the country to provide birds with an interconnected system — kind of a migrating landing strip. But, only a third of them are legally protected.
“Some of it is going to come true,” says Cheskey of the dire Audubon predictions. “Hopefully a lot of it won’t and birds will be able to adapt. More importantly, I hope we can still control our destiny rather than just letting it go whatever way it might.”
Some species are so hardy they can withstand almost anything and become nuisances, such as the Canada goose. Others, displaced from natural habitats south of us, are big-clawing their way toward Ontario.
The black vulture, says Cheskey, will likely be here in 50 years. “They’re recyclers. They feed on our detritus — dead carcasses of animals, garbage dumps, piles of food outside restaurants.
“They’re kind of like a Margaret Atwood futuristic scenario. I’m not saying we don’t want the black vulture here. But it’s a sign of what’s to come and maybe an omen.” Rosie DiManno usually appears Monday, Wednesday, Friday and Saturday.