“Common loons winter off our coasts. They summer in our backyards at cottages, so they are very vulnerable to human activity,” says Wright. “They are showing us what the health of our lakes is.”
What are the major inhibitors to common loon reproduction?
It will take years’ more study to know for sure, but researchers have three major concerns about the lake water that loons inhabit. Mercury—a pollutant released from the burning of fossil fuels—is found in many lakes across Canada, and is a neurotoxin that makes loon parents lethargic, less able to care for their young.
Second, acid rain that fell decades ago has killed off fish stocks that have yet to fully rebound in some areas. “Loons need lots of big, nutritious organisms, in the form of fish, to survive. But those are exactly the things that got knocked out of these lakes by acid rain,” says Mark Mallory, who has studied the effects of lake acidification on loons in the Sudbury, Ont. area. Recent research shows that, even after acidity has dropped in some lakes, the loons have not returned. “Nature is very resilient, and it may take a long time for things to decline,” says Mallory. “And correspondingly, it can take a long time for things to recover.”
The third main concern is climate change. To see a nesting loon panting in the heat, beak open and breathing heavily, is heartbreaking. But biologists who study loons believe that the effects are far more insidious: among other outcomes, warming waters cause an increase in methylmercury levels and cause bacteria to be more active. As Tozer says, “Climate change is going to be the big ugly thing in the background that’s causing a lot of this change.”
Loons are especially vulnerable to environmental change because they return to the same lake where they’ve laid eggs in the past, even if conditions are deteriorating. “This is hard-wired into their genetics,” Mallory explains. “They keep trying because they’ve defended the territory and they think everything else looks good about this site.”
The loon pair our cameras followed last summer in Algonquin were able to navigate the breeding season’s many challenges and raise two healthy chicks. Sitting in an edit suite watching the parents brave swarms of blackflies to stay on a nest or delicately manoeuvre their long beaks to carefully rotate an egg was awe-inspiring. To see them underwater, turning on a dime to catch a yellow perch, is to witness them at the peak of their powers. Both chicks grew at an astonishing rate—from tiny fluff balls to juveniles almost the size of their parents. It felt like a victory despite the larger question marks about the survival of the species.
In late fall, long after we close up our cabin each year, the young loons are left to fend for themselves. Their parents migrate first, leaving them alone on the frigid waters for several weeks. They feed and grow, building strength until just before the ice comes in. Then they too take flight, on their maiden journey south, as instinct guides them to do.
I only hope it continues for generations to come. For the loons’ sake and for ours.