The Wild Side, Part Four
Published August 26, 2012
By Margaret Munro
PORT ROWAN, Ont. – Jody Allair isn’t out of his truck two minutes when he tilts his head ever so slightly and picks up the song of a hooded warbler.
“There’s the male,” he says, as a tiny yellow bird flits away in the maples overhead.
Then Allair ducks into the forest, skips across a swampy patch and gingerly approaches a small shrub looking for the female. He gives the thumbs up.
“She’s sitting on the nest looking at us right now,” he whispers, pointing at what looks like a clump of dead leaves.
But Allair knows his birds – and he really knows “hoodies,” having spent 10 years with Bird Studies Canada helping document the hooded warbler’s remarkable recovery.
Sure enough, there is a female on a nest less than a metre off the ground.
Hooded warblers used to be one of Canada’s rarest birds. Fifteen years ago, there were believed to be about 100 breeding pairs in the country.
But the hoodies’ fortunes have improved – dramatically. The population is now estimated to be between 1,000 and 2,000 adult hooded warblers in Canada, and wildlife experts are recommending the hooded warbler be dropped from the list of 650 species at risk in Canada.
“To go from threatened to not at risk, that’s quite a leap,” says Marty Leonard, chair of COSEWIC, the Committee on the Status of Endangered Wildlife in Canada, the federal body that assesses at-risk species.
With so many birds in decline across Canada, Leonard says it’s great to see one bounce back, albeit for reasons that are not clear.
“The million-dollar question is why they are doing it,” says Debbie Badzinski, Ontario program manager for Bird Studies Canada, a non-profit dedicated to bird conservation.
She co-authored the COSEWIC report recommending the warblers be declared not at risk. She has also witnessed their recovery in a woodlot in southwest Ontario, where biologists have been tracking hoodies and the even more endangered Acadian flycatchers.
Both birds breed and nest in a region or eco-zone known as Carolinian Canada, one of the country’s major biodiversity hotspots.
Located in the southern tip of Ontario, the region is a tiny slice of Canada – less than one per cent – but is home to more than one-quarter of the country’s human population, some of its most productive agricultural land and nearly 25 per cent of its endangered species.
Many of them are songbirds that migrate incredible distances to seek out the few remaining remnants of Carolinian forest that once dominated the region.
The forests are just two hours outside Toronto, but they seem a world away.
There are 30-metre tulip trees, 400-year-old black gum trees and flowering dogwoods. There are spicebushes (their crushed leaves smell like citronella) and a butterfly, the spicebush swallowtail, to match. The rare southern flying squirrel is known to swoop between the trees and gray ratsnakes slither up them, at times raiding nests of equally endangered songbirds.
Acadian flycatchers, tufted titmouses and Louisiana waterthrushes nest here. So do hooded warblers, endangered prothonotary warblers and even rarer Cerulean warblers, a tiny blue bird that nests so high in the canopy that even Allair has trouble spotting it.
“I can go all day and not see one,” says Allair. That is saying a lot, considering that Allair helped set a new birding record in May. His four-man team saw 204 species in 24 hours, beating the previous Ontario “Big Day” record of 200 species.
It’s part of Allair’s job as a biologist with Bird Studies Canada – “the perfect job,” he says – to monitor birds in Carolinian woodlots which conservation groups are working to reconnect by buying up farmland.
One of the largest forest blocks – it’s about six kilometres across – is Backus Woods, where several of Canada’s endangered birds nest in and around some of North America’s oldest and biggest deciduous trees.
Allair is tuned in to every peep, trill and screech as he walks through the forest, rhyming off the names of the creatures responsible: scarlet tanager, red-eyed vireo, broad-winged hawk, Eastern wood-pewee.
He knows when birds arrive in the spring, whether they do – and, in case of some of the most endangered species, do not find mates – and how many young they raise.
“This is her second brood for this year,” he says, as he approaches one hooded warbler nest.
The male, with a bright yellow belly and what appears to be a black hood or babushka wrapped around his head, sings nearby. The female, greenish yellow with large dark eyes to help her see in the forest shade, jumps off her nest and chirps as she darts away.
“Oh, they are beautiful,” says Allair, peering down at three eggs. They are a bit bigger and fatter than jellybeans, creamy white and ringed with burgundy speckles. The cup-shaped nest of twigs and grass is anchored to the shrub with spiders silk and lined with tiny rootlets.
“The females puffs out her stomach like this and uses it to help shape the nest,” says Allair, as he does a stomach-puffing impression.
An intensive banding and monitoring program in nearby St. Williams forest has revealed some of the same hooded warblers return year after year from their wintering grounds in southern Mexico, Central America and Caribbean.
“Old Girl,” as they dubbed one female, was banded in 2000 when she was at least two years old and was spotted every summer from 2002 to 2009.
“The last time we saw her, she was 11 years old – remarkable for a bird that size,” says Badzinski. Hooded warblers, which migrate thousands of kilometres every year, weigh just 11 grams.
She usually built two nests each summer – chicks tend to trash the nests as they grow so new ones are needed for the second brood – and attempted a third in 2003 and 2008, the first time such marathon breeding has been documented, says Badzinski.
Over the years, Old Girl laid at least 51 eggs and successfully fledged at least 24 young.
“She was a breeding machine,” says Allair.
While Old Girl was one prolific bird, the monitoring program showed hooded warblers typically lay eggs twice each summer.
They also play the field. Old Girl mated with at least six different males but she did seem to favour one male that she mated with for three summers.
Several factors are thought to be fuelling the hoodies’ population expansion.
The warming climate appears to be shifting their range northward, and forest regrowth in northeastern North America has made for more suitable habitat, says Badzinski.
Hooded warblers prefer what scientists call “ephemeral” nesting sites: gaps that form temporarily in large mature forests when trees fall or are selectively logged, she says. They nest in shrubs and raspberries that sprout up in the openings.
“As soon as the raspberries take off they’ll move in, but once the trees get too high the birds will move on,” she says.
In recent years hooded warblers has moved on to forests near Niagara, Toronto and Peterborough.
Yet other songbirds in Canada’s Carolinian forest remain as endangered as ever. Acadian Flycatcher numbers continue to decline despite what seem to be plenty of good nesting sites, says Allair
They like cool dark shady spots, he says as he cuts through Backus Woods to check on a nest in the fork of a hemlock branch over a stream.
There are two flycatcher chicks in the nest – Allair checked with a mirror he had hoisted up on a pole when the female hopped off – and there is an attentive male nearby.
Other flycatchers have not been so fortunate. One female on Alliar’s radar this summer was keen to mate – so keen that she laid two clutches of eggs. But they were infertile because she could not find a mate.
“She gave it the best she could,” says Allair.
Less than 50 and perhaps as few as 30 pairs of Acadian flycatchers are believed to be breeding in Ontario’s Carolinian forests, and Allair says the situation could get worse if a blight killing hemlock trees in the U.S. moves into southwest Ontario.
While sad to watch birds that may be “at the end of the line,” he says it is important to document what is happening. Data on the birds can help drive and improve conservation efforts both in Canada and on wintering grounds in the south, says Allair, who is determined to keep the chorus in the forest alive.
“I like hockey and I like music, but I mean, what’s better than this?” he says, as the song of the male hooded warbler rings through the trees.
For more information:
Bird Studies Canada: http://www.bsc-eoc.org/
Carolinina Canada: http://www.carolinian.org/