'Backpack birds' return with data to solve mystery of purple martin population decline

Purple martins equipped with tiny GPS backpacks have returned to Ottawa from as far as Brazil with data Nature Canada researchers hope will help solve the mystery of the bird's declining population.

Nature Canada conservation manager Ted Chesky was part of a team that extracted the backpacks from the migrational birds at the Nepean Sailing Club in May where the birds live in individual apartment-like man-made roosts. 

"We put specialized traps just on the holes where we were pretty sure we had backpack birds," Chesky told Alan Neal on CBC Radio's All In A Day on Monday.

After the birds are trapped, their itty-bitty tracking devices, no bigger than a thumbnail, are removed, he said.

"Basically, there's a little harness, a little tether that goes around their body and we just clip it off with scissors. It comes off and we measure the bird and a few things like that then let them go," Chesky said.

Nature Canada's Purple Martin Project is part of an international effort by researchers and naturalists to restore the declining population. A thread-like antenna on the so-called backpack tracks the migration of a bird.

"With the geo-locators, we learn how fast they can do it and how much time they take at different points along the way, which is very interesting," he said, explaining the journey south is slow but the return north is quick in the spring. 

"It's a real fast rush to get back — and they don't all come back at the same time. The adult males tend to come back first, and they're followed by the sub-adult males then the females."

Chesky said researchers are still going through all the data, with the help of the Avian Behaviour and Conservation Laboratory in Manitoba.

"It doesn't take long — maybe a month or two — to download the data. But before any publication, that's about a year," he said. "We'll have a story to tell when we do that, which will be a very exciting story, believe me."

Listen to the full radio item here.

All in a Day7:15An update on the travels of the Purple Martin

And an update on a Nature Canada project, which involves purple martin birds getting outfitted with tiny backpacks that track their migration. Find out just how you go about slipping a mini-backpack off a bird to collect the data...