Bye-bye birdies: Shorebirds among species in decline in Metro Vancouver
Credit to Author: Kevin Griffin| Date: Wed, 02 Oct 2019 02:29:48 +0000
The good news for birds is that some species are increasing in Metro Vancouver. The bad news, however, is a dismal downward spiral in overall numbers.
Local bird experts say a recent analysis that showed a drop of 2.9 billion birds, or 29 per cent, since 1970 in North America, is reflected in Beautiful B.C.
Decline of the North American avifauna was published in the Sept. 19 issue of the journal Science. It used independent monitoring networks to count birds in Canada and the U.S. during the past 48 years. The analysis looked at 529 species representing 76 per cent of bird species but almost the entire number of birds.
“This loss of bird abundance signals an urgent need to address threats to avert future (regional bird-population) collapse and associated loss of ecosystem integrity, function and services,” an abstract of the article says.
The analysis found big drops in aerial insectivores such as sparrows, blackbirds and swallows.
In Stanley Park, a program has been in place since 2009 to rebuild one of those species: tree swallows. The Stanley Park Ecology Society puts plain wooden nest boxes built by volunteers on poles in Lost Lagoon. Last year the society increased the number of nest boxes for tree sparrows from six to 15. There are also six nest boxes for wood ducks.
Meghan Cooling, a conservation technician with the society, said even though the program has been a success, it isn’t being expanded. Simply adding more nest boxes won’t work for tree swallows. In nature, tree swallows usually nest in cavities in trees over water, often in beaver ponds.
“The nest boxes need to be a certain distance part. There is only so many we can put in Lost Lagoon,” she said. “Once they’re too close together, the birds don’t want to use them because they’re encroaching on each other’s territory.”
Cooling said the society tried to put nest boxes for tree swallows on the Nature House on shore underneath the plaza at the north end of Alberni Street. That didn’t work well. Other invasive cavity-nesting birds such as house sparrows invaded the boxes, killed the inhabitants, and used the box for themselves.
“We like to keep them over the water so that we’re not inadvertently helping invasive species,” she said.
The overall trend in Metro echoes both the analysis released earlier in September and the State of Canada’s Birds 2019report released earlier this year, said David Bradley, director of programming for the B.C. program office of Bird Studies Canada.
“It clearly shows a decline in shorebirds, air insectivores such as swallows and swifts, and also grassland birds which you don’t find so much in Vancouver,” he said.
The Stanley Park Ecology Society started its nest-box program in 2009. There are now 15 boxes for tree sparrows. Photo: Meghan Cooling
The B.C. Coastal Waterbird Survey shows steep declines of shorebirds such as dunlins and sanderlings.
“Their numbers have declined quite a bit since the survey first began 20 years ago,” he said. “It is actually quite scary that birds like that have declined. They were so numerous in the past.”
Western screech owls are another species that have declined to the point that they’re considered a species at risk. They used to be found in woodlands around Vancouver and in Stanley Park.
“Up to year 2000, they were seen regularly on Christmas bird counts,” he said. “They’re just not seen anymore.”
Bradley laid much of the cause of the overall drop in bird numbers on habitat loss, the impact humans are having on the environment, pesticides and household cats.
“We know that cats have a very significant role in bird decline,” he said.
Some species, however, have increased. Successful urban adapters include resident Canada geese and crows. Birds of prey such as bald eagles and peregrine falcons have increased 110 per cent from historic lows since the widespread use of the insecticide DDT ended in the 1970s.
Direct human intervention may be the reason why Anna’s hummingbirds have also increased.
“I have a personal story,” Bradley said. “In 2005, I found the first Anna’s hummingbird to be seen at the Christmas bird count in Vancouver. They hadn’t been seen before. Now there are hundreds.”
The increase may be due to the local effects of climate warming and the popular use of hummingbird feeders.
Overall, Bradley said, human changes to the environment are harming birds.
“There’s good-news stories in there as well,” he said. “But ultimately, we’re stressing the environment too much, putting too many pesticides on the ground, using too much habitat for our own purposes and not taking birds into account.”
At the Wildlife Rescue Centre in Burnaby, Janelle Stephenson is the hospital manager. She said the centre is seeing several different changes including an increase in overall numbers and more rare species coming into the hospital for treatment.
“We’re on the front line of what’s happening to the animals and what’s killing them,” she said.
In the last 10 years the number of animals treated in the hospital has increased from about 3,000 annually to around 5,000; 90 per cent are songbirds.
In some cases, extensive habitat loss due to forest fires has caused some bird species to change their migration patterns from the interior of the province to available green space in Metro. When species move to a new habitat, they don’t always successfully adapt to an urban setting.
“We see a huge shift of species to urban areas because that’s the only green space left,” she said.
A male tree swallow feeds his chick in one of the nest boxes in Lost Lagoon installed by the Stanley Park Ecology Society. Photo: Frank Lin
Bird Studies Canada’s top-six ways to help birds
Get to know birds:
Learning to identify birds is one of the best ways to connect with the natural world. It’s considered the first step toward conservation.
Support bird conservation:
Joining or volunteering for a bird-conservation group can make a difference in helping birds.
Be a bird-friendly consumer:
Consumers can check to ensure coffee and other products are certified as bird-friendly.
Make your yard bird-friendly:
Native plants such as sunflowers and thistle that go to seed provide food for birds in the summer while fruiting trees such as mountain ash and serviceberry attract bluebirds, robins and waxwings.
Keep cats indoors:
An Environment Canada study in 2013 estimated that cats kill more than 100 million birds a year across the country. Bells on collars aren’t effective in stopping cats from killing birds and other wildlife. What works is keeping them indoors.
Prevent bird-window collisions:
An estimated 25 million birds a year are killed by colliding with windows. Bird baths and bird feeders should be kept a safe distance from windows — at least a metre.
— From Bird Studies Canada