Birds disappearing? No way, you might scoff.
There are still lots of birds around, you say. And you’d be right.
But what most of us are seeing are what bird experts call generalists — birds that tend to have little trouble living alongside people.
Birds such as crows, blue jays and pigeons. Or starlings and house sparrows, although even their numbers are down somewhat in Nova Scotia.
Less obvious — unless you’re specifically looking — is that populations of a wide variety of other bird species found in and around this province have been shrinking for decades.
The hardest hit? Songbirds and seabirds.
“You can’t help but notice things are changing,” says Eric Mills, vice-president of the Nova Scotia Bird Society and an active birder for more than half a century.
“We see the abundance of birds going down,” says Mills, professor emeritus of science history at Dalhousie University. “Year by year, there are fewer birds coming through, in some species anyway. The ones we value the most, frequently. We all see it.”
Chimney swifts and swallows, warblers and blackbirds. Terns, murres and puffins. All have declined in number, some so precipitously they’ve been declared endangered.
The grim news regarding birds, of course, is hardly confined to Nova Scotia.
One in eight bird species on Earth is now in danger of global extinction, according to The State of the World’s Birds, a 2013 survey by Bird Life International, the world’s largest nature conservation partnership, made up of non-profit NGOs and as many as 10 million members and supporters worldwide.
That’s worth repeating. One in eight of all bird species worldwide could disappear.
Here in North America, more than a third (37 per cent) of the 1,154 bird species native to Canada, the continental U.S. and Mexico need urgent conservation efforts to help them survive, warned an assessment released last May by the North American Bird Conservation Initiative.
The most threatened category is oceanic birds, according to the tri-national The State of North American Birds 2016. Nearly half of all seabirds (45 species) are on NABCI’s Watch List.
The same survey ranked coastal birds, including sandpipers and plovers, the third-highest category of concern (37 per cent of 164 species).
Then, just last month, a new survey of North America’s 448 land-based bird species reported the continent has lost a staggering 1.5 billion breeding birds — many of them songbirds — since the 1970s.
Nearly one in five types of North American land birds — 86 of 448 species — need urgent action to help stem steep population declines, according to The Partners in Flight Landbird Conservation Plan. The work, an update on PIF’s previous survey in 2004, was produced by a network of more than 150 partner organizations throughout the Western Hemisphere.
Ken Rosenberg of the Cornell Laboratory of Ornithology in New York, a co-author of the PIF report, says it's difficult to calculate the total number of breeding land birds in North America, but estimates range from two billion to five billion. So the missing 1.5 billion represents a significant loss.
What’s happening? Why are so many bird species under threat?
The reasons, experts say, are wide and varied.
Climate change. Diminished food supplies. Man-made destruction and alteration of habitat. Pesticide use in agriculture. Dangers posed by man-made structures and related activities, such as gas flares. Predation by cats, both feral and house pets allowed to roam outdoors (experts point out native North American bird species evolved for millions of years before cats, brought here by Europeans less than 500 years ago, arrived, so native birds are often extremely vulnerable to the introduced predators).
On offshore islands, invasive rats and feral cats have often devastated nesting seabird colonies.
For land-based migratory species, like songbirds, “it’s all of these issues combined causing these ongoing declines,” says Judith Kennedy, another co-author of the recent Partners in Flight report and head of the migratory birds conservation unit at Environment and Climate Change Canada in Gatineau, Que.
Habitat change and loss are the primary problems, she says. But those other factors are putting even more pressure on stressed populations.
“A bird may reproduce and get their young out of the nest but then they’ve got to migrate,” says Kennedy. “And so, in the migration, they have the risk of running into buildings, they have the risk of being preyed upon by cats, they may run into a gas flare, they may go to land somewhere and there’s no habitat (or food) on the migration route.
“Or they may get to their final wintering destination and they have all of those same threats at that end, as well.”
Even human-produced light pollution can disorient migrating birds, according to The Messenger, a moving documentary about the ongoing disappearance of the world’s songbirds.
The film, made by SongbirdSOS Productions, a Toronto-based independent production company, and released in 2015, was screened at Dalhousie last month.
One scene in the film shows the memorial to the missing World Trade Center towers in Manhattan — large spotlights pointing skyward to mimic the downed twin towers — inadvertently drawing thousands of confused migrating birds down toward the lights. Officials, on hand specifically to monitor bird behaviour, eventually shut off the lights.
Another threat comes from wind turbines, which kill between 140,000 and 328,000 birds annually in North America.
Climate change is also affecting food supplies, says David Currie, a birder for 50 years and, for the last four years, president of the Nova Scotia Bird Society.
The timing of insects hatching, relied on for food by migratory birds returning to the province to nest, has been altered by changing temperature patterns, he says.
Some birds, like tree swallows, seem to adjust and now arrive almost two weeks earlier each spring, says Currie. But others, like bank swallows — once much more abundant in Nova Scotia than they are today — have not adapted as well.
Meanwhile, the biggest problem for seabirds off our coasts seems to be lack of food, says Currie.
Warming waters due to climate change are driving many of the fish that seabirds feed upon to colder, deeper waters, many experts say.
That means more competition from other seabirds and, at times, fishermen, for the remaining fish, says Mills.
“There’s just not enough food close enough to the (nesting) islands,” Currie says. “If they have to go two days away to get the right amount of food to bring back to the chick and (as a result) the chick is not viable anymore, it’s a wasted trip.”
In recent years, there have been news reports of puffin chicks starving to death on Machias Seal Island in the Bay of Fundy. Similar stories have been reported about northern gannet chicks off Newfoundland.
Ian McLaren, a conservationist, author (All the Birds of Nova Scotia, 2012) and retired professor emeritus of the biology department at Dalhousie, says predation by gulls and bald eagles — the latter one of the success stories in rebuilding a bird population — on seabirds during breeding season off Nova Scotia is also a problem.
Surprisingly, all species of gulls and even land-based starlings in this province have declined in the last half-century, according to statistics on Nova Scotia bird species from the North American Breeding Bird Survey 1966-2013 Analysis, done by the Patuxent Wildlife Research Center in Laurel, Md.
The reasons are similar and relate to food supply, says McLaren.
“In the mid-20th century, they (gulls and starlings) were considered out of control because of the abundance of open landfills and garbage pits … filled with organics and, in the case of gulls, a large and wasteful fishery and lax regulations about effluents from fish plants.
“By the late 20th century, in Halifax and elsewhere, landfills and fish plants became cleaned up and the fisheries diminished, and both gulls and starlings began to crash.”
Of course, thousands of people were devastated by the fisheries downturn. And cleaning up dumps was the right thing to do. But such examples show just how much bird populations can be affected by human activity.
In Nova Scotia, the government lists the barn swallow, Canada warbler, rusty blackbird, Bicknell’s thrush, red knot, chimney swift, roseate tern, piping plover and harlequin duck as endangered bird species. Several more species are considered threatened or vulnerable.
The challenges are daunting, but the situation is far from hopeless, says Kennedy. People have responded with solutions before.
She cites the example of the successful recovery of many bird species after DDT use — which caused eggshell thinning in birds higher in the food chain, like raptors and pelicans — was scaled back in the ’70s.
“That’s a great example of, you know, you identify the problem, you take the action and you have the confirmation outcome that you’re looking for.”
Mills mentions ongoing worldwide efforts to rid vulnerable seabird nesting islands of rats and other invasive predators. When successful — as on South Georgia in the South Atlantic — bird populations can recover amazingly fast.
Currie points to how, when people realized duck populations were in decline, campaigns were launched to protect and restore wetlands.
“Ducks Unlimited became involved, hunters became involved and it became a rallying call. So you have all these beautiful wetlands around now and waterfowl are doing great.”
But, cautions Currie, the crisis now “is a much harder one to deal with.”
So what, if anything, can be done?
Because the pressures on birds are so many and varied, there’s no one answer.
“There are lots of best-management practices for sustainable forestry and agriculture that we can implement,” says Kennedy. “That can minimize the amount of impact on birds and other wildlife. It’s not that we have to go back to living a completely natural life, but reducing the impact we’re having could be super helpful.”
In Nova Scotia, Currie and Mills both say, provincial governments, in particular the Department of Natural Resources, have contributed to degradation and destruction of bird habitat by allowing forest practices such as clearcutting and the burning of biomass for energy.
Currie acknowledges habitat loss is a problem that spans the continent and beyond. But, he says, Nova Scotia’s got an important role to play.
“We owe it to Mexico, we owe it to the U.S., to protect the habitat that’s so important for these birds as they come up here to breed. If we don’t have any place for them to breed, it’s going to be really quick before they can’t sustain the numbers they need to continue to be here.”
Meanwhile, despite decades of discussion, the province still doesn’t have a coastal policy to govern development and other shoreline issues — to the detriment of coastal birds, says Mills.
Mills also says he’d like to see fishing fleets ease off their efforts near islands where seabirds nest.
“Find ways of sharing stocks like herring with whales and seabirds. In other words, reduce the human catch.”
That may sound like sacrificing jobs, but — if it would help — surely there’s a middle ground, a way to make allowances for breeding seabirds at critical times of the year.
What about smaller steps, the kind of stuff an individual can do?
Bird Studies Canada, a national charity for bird research, citizen science, education and conservation, offers a list of ways people can help birds.
Another group working to safeguard birds in urban environments is Flap Canada.
And, if you own one or more cats, bird experts ask you keep them from harming wildlife.
“The main thing is just not to allow cats out to roam freely,” says Kennedy, “especially during the migration seasons, when birds are coming through in big numbers and many of them are tired and feeding on the ground.
Kennedy recommends catsandbirds.ca as a website showing how cats and birds can co-exist.
The problem is not trivial. Feral cats, especially, have been linked in studies around the world to declining wildlife numbers, including birds. Feral cats have contributed to the extinction of 33 island-based bird species globally.
House cats let outside, however, can also cause huge damage to bird populations. A study by Environment Canada scientist Peter Blancher estimated cats (62 per cent ferals, 38 per cent pets) kill anywhere from 105 million to 348 million birds every year in this country.
About a quarter (115 of 468) of bird species found regularly in Canada are vulnerable due to their nesting or feeding behaviour, said Blancher.
So there are fewer birds, some might say. So what?
“Birds provide a lot of other ecosystem services,” says Kennedy. “They pollinate plants. They spread seeds. They consume insects. They have an important role to play in the ecosystem.” And their habitats serve humans, by providing oxygen and helping maintain the water table.
“The more species we have around us, the more they interact in complicated ways and the more stable the natural systems are that we depend on," argues Mills. “We can expect to see more uncertainty in our environments, in our surroundings, if we have fewer species of plants and animals of all kinds, including birds.”
“Birds represent an indicator of the well-being of the planet," says Currie, “as they are literally the canaries in the mines. It’s more than not hearing birds sing and missing what once was."
Currie, now retired after a career in insurance, was originally drawn to birds by their immense variety and diversity. He says he loved learning about each species’ behaviour and their unique niche in the ecosystem.
“I think we will still lose birds to extinction due to our inattention and ignorance, but I am optimistic when I see the young minds out there in science who are dedicating their lives to finding solutions.
“This has been a passion for me for 50 years,” says Currie. Seeing birds in abundance “makes me feel good … that things are right with the world.”