Endangered Ontario: The mysterious migrations of the 'butcher bird'

Every winter Ontario’s 50-odd loggerhead shrikes pack up their nests and fly south. They don’t call. They don’t write. And oftentimes, many of them don’t come back.

Wherever the endangered birds spend the winter, they’re suffering. But despite banding the shrikes’ legs and using tracking technology, researchers haven’t been able to find out where that is.

“If the things that are hitting our birds hardest are happening either while they're migrating or on their wintering grounds, then we need to know where they're going and how they're getting there,” says Hazel Wheeler, lead biologist with Wildlife Preservation Canada’s loggerhead shrike recovery program.

Shrikes are distinguished partly by their peculiar eating habits. They impale their meals — creatures such as mice, grasshoppers, and toads — on barbs and on thorns, tearing their food apart with their sharp, hooked beaks. They sometimes get creative with their villainy, using barbed-wire fencing to skewer prey.

Shrikes were common in Ontario until about the 1970s, when their numbers began to decline precipitously. Now only two populations remain: one in Carden Alvar Provincial Park, near Orillia, and one in the Napanee Limestone Plain, near Ottawa.

Wheeler says there isn’t just one reason the birds are disappearing. “Habitat loss is of course always an issue,” she says. “We've done some analysis that shows overwinter survival of first- and second-year birds seem to be the most sensitive sector.”

Banding helps only so much. In order to keep track of where the shrikes migrate and address the threats that exist there, someone needs to spot them, record the sighting, and send it back to Ontario.

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WPC’s shrike recovery group attached geolocators to more than 190 birds between 2009 and 2014. Only eight were recovered, and just two contained usable data. “The tricky thing is you need to recover them to get the data,” Wheeler says. “The average return rate for loggerhead shrike in the wild is about 5 per cent of juveniles that are born in Ontario.”

The data wasn’t accurate enough to determine the overwintering location.

Some studies point to Virginia and West Virginia as possible shrike destinations, but results are still preliminary, according to policy analyst Kristina Hubert of the Ontario Ministry of Natural Resources and Forestry.

WPC has been working with groups in the U.S. to pinpoint exactly where these birds are going. They’ve also been using Motus, a radio telemetry network that tracks birds through their migration. But the system works only where there are signal towers, which require buy-in from governments, conservation groups, or birding enthusiasts. The network hasn’t yet produced valuable information on the shrike.

Since 2001, the province and partners have bred and released hundreds of shrikes . While Ontario’s current 23 breeding pairs may seem like a small population, that’s bigger than it’s been in years past.

“When you compare that to two years ago when we had 11 pairs in the wild, this is a vast improvement. That was pretty much a year of despair for me,” Wheeler says. “It just seemed really bleak. There were often single birds floating around on territories and calling for a mate, but no mates were showing up. It was just really sad.”

Video by Matthew O'Mara