When we lived in Jasper I used to fish until midnight in early summer. Big, brown drake mayflies hatched as the light faded and big rainbow trout moved into the shallows to feed on them. I usually brought one or two fish home to eat.
One night while cleaning a trout I noticed that its stomach was distended and hard as a rock. I cut it open and out spilled a mass of big, black carpenter ants. That trout had gorged itself on them; to my biologist eyes it was an awesome sight. But the family was all asleep, so I had nobody to admire the mess with me.
No problem: I scooped all the ants into a cereal bowl and left it on the counter. They’d see it in the morning. Then I cleaned up, tucked the trout into the freezer and went to bed.
When I came downstairs in the morning, Gail met me in the hall, glaring, and pointed an accusing finger at me.
“What??” My sleep-muddled mind was racing, trying to think of what I had done.
“You get in there and clean up that mess,” she said. “What on earth were you thinking?!”
That was the day I learned that ants inhaled by trout can end up only stunned, not dead. The kitchen was crawling with them: on the curtains, under the stove, on the fridge, everywhere. Some were even flying around. No leisurely breakfast that day; I spent the next hour chasing bugs.
A lot of people have carpenter-ant problems, but rarely such self-induced ones. Out in the forest where they belong, carpenter ants live in old logs and dying trees. But sometimes the wood in our homes meets their nesting criteria too and they become unwelcome guests. Their nests are literally chewed out of damp wood; carpenter ants gnaw long galleries and rooms into the material to make homes for their queen ants and larvae. In the forest, that’s a good thing; their work helps recycle dead wood into the soil. In your house, it’s bad news.
Since all the ants in a colony are descended from a single queen, inbreeding is a risk. Carpenter ants avoid that problem by holding aerial orgies. In midsummer some of the new hatchlings grow wings. Then they take to the sky. In those swarms of flying ants, males from many other ant colonies mate with the winged queens-to-be, ensuring genetic diversity while also wearing themselves out. Inevitably some of the tired ants fall into streams and lakes where hungry trout are waiting.
Ants have to accumulate a lot of energy for their mating flights. That makes them attractive food to trout, swifts and gulls.
Being inefficient fliers, ants have to accumulate a lot of energy for their mating flights. That makes them attractive food for other creatures, too, such as gulls. One day as I drove across a burned-off mountainside deep in the Rockies I was surprised to see a flock of Franklin’s gulls—small, graceful, black-headed birds often seen above Alberta cities—wheeling, dipping and diving among the dead spars. They had flown deep into the mountains, guided by some mysterious knowledge to which we humans are not privy, to feed on the winged ants emerging from those fire-killed trees.
Not far from the lake where I caught that ant-packed trout, the Maligne River drops out of a hanging valley to rendezvous with the Athabasca. The narrow, deep canyon it has carved there is a popular attraction for visitors to Jasper National Park. Those who linger into the evening are sometimes treated to the sight of graceful, long-winged birds tilting down out of the darkening sky and vanishing into the shadows below.
Those are black swifts, a rare species that nests only in places with very high humidity, low temperatures and day-long darkness. Alberta has fewer than 10 black swift nesting areas, all in deep mountain canyons, caves or behind cascades. In the mountain parks, those include Maligne and Johnson canyons. There, the swifts build nests of moss, lay a single egg and raise a single young each summer.
Swifts feed only in the air. Like Franklin’s gulls, they have an uncanny sense of where to find swarming insects, often travelling tens of kilometres to gorge themselves on bugs. Flying ants are a favourite—easy to catch and highly nutritious.
Biologist Geoff Holroyd, who has made a life study of aerial-feeding birds, suspects that swifts nest in such seemingly hostile environments not just to avoid predators but also because their young have to wait so long between meals; swifts feed their offspring only once or twice during the day. Young swifts apparently conserve energy by going hypothermic between meals of protein-rich ants.
There are lots of dead trees out in the forest these days. Don’t mourn them; cheer them for housing all those carpenter ants. Without dead trees and ants, fewer trout would dimple evening lakes, and the sky above and canyons below would be emptier places. These are the things that give grace to the world.
Kevin Van Tighem’s Wild Roses Are Worth It: Reimagining the Alberta Advantage was published in spring 2021 by RMB.
