2019 - 2020 Loon News
The raft in the picture is one that our Stewardship Team Garnet Baker, Gary Nielsen and Dwayne Struthers built about 15 years ago. After several years, the logs and flotation became waterlogged so we decommissioned it. A couple of years ago I decided that I would tow it out to Muskrat Island for the turtles to bask on. Every fall I towed it back in and tied it to my dock until the next spring. I hurt my back in late August 2019 so we moved home early and I forgot to pull in the raft.
In May 2020 when I went down to rake the leaves I noticed a pair of loons inspecting the raft. It sure wasn’t an ideal location as the platform was partially sinking and the only nesting material on it was from an abandoned muskrat house. Also the island is a very popular with the fishing folks and all the neighbours, kids and dogs enjoy swimming and jumping off the rock there. After circling the raft a couple of times, one of the loons hopped up and after a quick inspection settled down on the muskrat’s sparse vegetation. A few hours later when the loon left and I checked the nest from our deck with my binoculars I could see at least one egg. A few days later there were two.
I knew then that we were going to have to limit our swimming activities with our dogs for a while because the raft was beside our swimming lane to the island. The incubation period for loon eggs is usually 26–30 days so I thought if I talked to the neighbors, we might be able to protect the nest until the eggs hatched.
It was quiet for the first week and most people gave the platform a wide berth but the traffic really increased during the next two weeks. The loon was constantly under stress as people were paddling too close or sometimes right up to the platform so she was off the nest a lot. Loons do leave the nest for a day sometimes when they are laying their eggs. As soon as they start to incubate the eggs one of them is usually present to protect and keep the eggs warm.
A week after the eggs should have hatched, I realized that the nest was probably going to be unsuccessful. I didn’t want to interfere with wildlife as I knew they would eventually abandon the nest. The male finally quit coming to the nest but the female was an excellent parent and stayed on the nest for an additional three weeks. Unfortunately this was when we had that long stretch of hot weather and it was sad to see her panting while she was sitting in the hot sun all day. Several times during the day she would take a short break to cool off, catch a quick meal but then climb right back up on the raft. She would carefully turn the eggs over each time and then settle down on them. I kept hoping she would leave and I was tempted several times to go out and remove the eggs. I contacted the local authorities for advice but was told not to interfere and let nature take its course. She finally did abandon the nest and I removed the eggs.
It’s quite common for loons to lay more than one egg and they don’t always all hatch. When I opened the eggs there were no embryos. I don’t know if the nest failed because the eggs were infertile or if they got too hot when she was stressed and off the nest repeatedly in the early weeks.
CLA/CLEA staff and volunteers will be erecting loon information signs at several locations around the lake this year on how boaters can protect our loons.
Our adult loon populations and chick numbers do fluctuate from year to year and we usually have 24-39 adults on the lake during the summer months. Since 2010 the annual chick populations have varied from 4-9 chicks and in 2019 a total of 6 chicks hatched.
When I did the final survey for 2020 all 3 chicks on the north end of the lake had survived and Bill and Janice Hallam confirmed 3 more on the south end. Our new rafts continue to successfully provide nesting habitat for most of our young chicks on the lake. Please give our nesting loons and young chicks a wide berth.
Dwayne Struthers, Fish and wildlife Director
Fewer Surviving Chicks Spell Trouble for Loons
Ontario’s common loons, a species symbolic of northern wilderness, are rearing fewer chicks to maturity, a new study reports. The research, based on Birds Canada’s volunteersupported Canadian Lakes Loon Survey data, suggests that this decline in reproductive success has been underway for four decades.
According to study co-author Kristin Bianchini, a postdoctoral researcher working with Acadia University and Birds Canada, loon populations are currently stable but fewer surviving loon chicks could mean fewer adult loons. And since loons are indicators of ecosystem health, their reproductive diffi culties suggest serious problems with Ontario lakes.
Researchers measure loon reproductive success by the annual number of six-weekold chicks pairs of loons have. By that point in their development, young loons are nearly two-thirds of adult size and are able to elude predators. Ontario loons successfully raised 0.8 six-week-old chicks per pair per year in the 1980s. Now, they raise fewer than 0.6 sixweek- old chicks. Other studies suggest that if this rate falls below 0.48, the number of loon adults may decline. “Our study shows that Ontario may be on its way to dipping below the 0.48 threshold,” says Bianchini.
What is behind this decline? Acid rain caused by air pollution in the 1970s and 1980s deposited toxins such as aluminum and mercury in Canadian lakes. These toxins deplete fish stocks on which loon chicks rely for food. Accumulated mercury also affects loon behaviour, decreasing nest incubation, chick feeding activity and the young birds’ resilience. Warmer conditions due to climate change may further raise mercury levels in the food chain, the study suggests.
Loons encounter other challenges in rearing their chicks, including shoreline development and boating activity. Cottagers and homeowners can help by letting shoreline native plants grow to provide shelter for loons and support habitat for species the birds eat. Additionally, minimizing the presence of boats and their wakes can lower the risk of damaging loon nests or separating adults from their progeny.
People can also advance research by participating in the Canadian Lakes Loon Survey. The upcoming third Ontario Breeding Bird Atlas, on which fieldwork will start in 2021, will reveal more details about loon and other bird population trends.
For both new and seasoned naturalists, the call of the loon is indelibly connected with Ontario’s wilderness areas. “To me, hearing loons has always been associated with being in a secluded wild place,” says Cecilia La Rose, a member of Ontario Nature’s Youth Council. “The sound has made me happy for as long as I can remember.” Ontario Nature hopes future generations of nature lovers will continue to enjoy those iconic sounds.
Many thanks to Ontario Nature and the author Noah Cole.