Researchers hoping small Purple Martin birds can offer up big answers

They chirp and sing, they jockey for the penthouse suite of human-constructed apartments, and make a long trek to Brazil every fall. 

Their aerial acrobatics are something to behold, and their colonies delight people who have devoted themselves to their survival. 

But despite the best efforts of bird lovers and researchers, the Purple Martin, a type of swallow, are on the decline, their population down overall 60 per cent since the 1970s, and down closer to 90 per cent in Ontario. 

“They’re really lovely birds. I just can’t wait for the first ones to arrive in the spring,” said Kathryn Boothby, of Fairnorth Farm, in Norfolk County, Ont. She’s been hosting a colony of Purple Martins for nine years. 

This past week, a PhD student from the University of Manitoba, along with researchers from Nature Canada, were on Boothby’s property, along with other places in Ontario, to catch up to 50 of the birds, measure them, and outfit them with tiny radio transmitters in backpacks that can track their migration patterns. 

80 per cent of juveniles lost

Researchers put a radio transmitter backpack on a Purple Martin in Norfolk County, Ont., (Kate Dubinski/CBC News)

“In each migration, we lose about 80 per cent of juveniles. We want to know how the period before their migration impacts on whether or not they will be lost,” said Saeedeh Bani Assadi, who is working on her doctorate with a lab at the University of Manitoba. 

“The young ones, they don’t have the knowledge of the adults. The juveniles are becoming independent, but they don’t have the knowledge of their parents. They have to learn to hide themselves from the predators, to find their way back to their nests, to their breeding colonies. I want to find out as much as I can about the little ones so we learn more about the migration ecology of the Purple Martins.” 

Purple Martins still declining

Kathryn Boothby, of Fairnorth Farm in Norfolk County, Ont., is a Purple Martin landlord. She is helping researchers catalogue some of the birds. (Kate Dubinski/CBC News)

Tagging the birds and outfitting them with radio transmitter backpacks is painstaking work. 

First, researchers must sit quietly, watching the apartments the birds live in, and when a Purple Martin enters, they pull a fishing line string to close a door that traps the bird inside. Next, the apartments are lowered, the bird is removed, and he or she is measured. 

Next, researchers put a band on the bird and attach the radio transmitter. 

“We have been doing work to help recover populations of Purple Martins for the past five years,” said Ted Cheskey, the naturalist director of Nature Canada. 

“There’s big networks of Purple Martin landlords, like Kathryn, who talk to each other, and we go to their properties to do the work we do. One element of the work we’re doing is to improve the housing.” 

Nature Canada’s work is focused on east Ontario and the Lake Erie basin, Cheskey said. 

“Purple Martins are the largest member of the swallow family, and they are aerial insectivores. It’s the group of birds that is declining the fastest. Birds of prey, water fowl, they’ve done well since 1970, but shorebirds, grassland birds and aerial insectivores, it’s bad news.

“The tags will help us answer questions about what they do when they leave their colonies, because there’s a time gap between when they leave their nests and when they leave for Brazil. They gather in these large colonies, thousands of birds, and they gather along the Great Lakes — one at Long Point, along the Grand River, at Point Pelee. They stop over, fatten up, prepare themselves for migration.” 

If researchers can determine where the populate drops off, they can try to mitigate the birds’ decline, he said. 

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