Swarms of 'scary-looking' stoneflies may freak out people but delight birds

It's more than just the high water levels that have had the Bow River buzzing where it flows through Calgary.

Swarms of insects continue to hatch along the banks, attracting birds that feed on them, says Calgary Homestretch naturalist BrianKeating.

"There's been an emergence of adultstoneflies, with breeding swarms," he told host Doug Dirks. "The other night when the sun was low, it back-lit these breeding swarms and it looked like cottonwood fluff."

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Theswarms present "a huge protein opportunity" for all different kinds of birds, addedKeating.

"I've got a robin nest in my backyard and the adults are feeding non-stopstonefliesto the babies. I've got a flicker nest in my backyard and the adultflickers are bringingstonefliesto their young. I've seen flycatchers and waxwings and king birds and even ducklings and goslings feeding on them along the river."

They're also attracting large numbers of Franklin's gulls named after Arctic explorer John Franklin which are also known in Alberta as the prairie dove.

"They're a very sleek and very handsome, black-headed gull," he said. "They're stunningly beautiful."

And the gulls are also great fliers, able tooutmanoeuvrethe small insects.

"This gull is exceptional," saidKeating. "And now, after the emergence of thestoneflies, it's giving us some tremendous visual opportunities on the river. [The gulls] are a thing of beauty to watch."

Stonefliesmay look tasty to a bird, but they freak out most people, saidKeating.

"It's kind of a scary-looking insect," he said. "It's got a big, long abdomen that is thick, and it's a fairly slow flier, and a clumsy flier, so it often lands on you, which freaks some people out, or it lands in your meal while you're sitting outside."

Alberta has nearly half of the 250 species ofstonefliesfound in Canada.

"Stonefliesneed fast, cold, clean, unpolluted, flowing, high-oxygenated water to survive," he said. "And that's why the Bow happens to be perfect for it."

The bugs feed on submerged leaves and algae, then adults will lay up to 1,000 eggs at a time to continue the lifecycle.

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With files from theCalgary Homestretch.