This has been a devastating spring for loons in northern Wisconsin and Minnesota wth 70 % of loon nests abandoned. The host specific black fly species, simulium annulus, feeds exclusively on the Common Loon. Forever bothersome to nesting loons, these flies appeared in larger than normal swarms this year. According to Walter Piper, a Chapman University researcher of loon behavior in Wisconsin, the late ice out and late snow melt is part of what causes an extra large population of these flies, which differ from the black flies that leave huge welts on our human hairlines and pollinate blueberries.
Simulium annulus flies feed on a loon’s head as they sit on their nest, causing the loon to continuously dive off the nest to try to rid themselves of the pests. However, even when loons swim underwater, the flies can still stick to the loon’s head. Whenever the loons dive underwater to escape the flies, the eggs are exposed to cold and predation.
On Hungry Jack Lake, a loonwatcher observing a loon nesting on a man-made platform reported a huge cloud of flies swarming the loon’s head that was visible without binoculars from 100 ft away. That loon repeatedly got off the nest to dive and then had to fight off a crow going for the exposed eggs. The pair finally abandoned the nest and after one week the eggs were taken to the DNR office in Grand Marais to be transferred to Grand Rapids, MN for contamination studies.
This tragedy of events also touched the loon pair who nest on the man-made loon nesting platform in the Chik-Wauk Museum bay. Over the winter, the platform had broken loose and when Kathy and Mike Lande towed the refurbished platform back to the nesting site in mid-May, the pair swam alongside, diving under the canoe and pecking at the platform. The loons started nesting on May 19th and had been on the nest for two weeks before the flies hatched. The pair abandoned the nest after 20 days of incubation, 8-10 days short of hatching. When Kathy went out to the nest a week after it had been abandoned, there were no eggs so it is assumed that the flies drove them off the nest and a predator got the eggs. Although the pair stayed around the nest for awhile and showed signs of renesting, they finally swam away. Sadly after two successful nesting years in 2011 and 2012 producing two chicks each year, both 2013 and 2014 have been unsuccessful nestings.
Some of the pairs on Gunflint Trail lakes renested, with chicks hatching in mid-July. This is very late in the season for loon chicks to be hatching and the loons now have a finite amount of time to learn how to survive on their own before the autumn migration.
Now is the time for boaters to be very “Loon Aware” as chicks in their first three-four weeks are very vulnerable, especially to speeding watercraft and boats pulling waterskis and tubes. Anglers should be cautious when loons are near, since bait on the end of a line looks like free lunch to loons. Loons may dive for the bait, swallowing hook and line.
The re-nesting loon on Hungry Jack Lake has a fishing line dangling from his or her beak. When the loon is not on the nest, it spends more time trying to get out the line than eating. DNR officials contacted say it is impossible to catch a loon and remove the hook, so the loon will most likely have a slow and painful death. Local business owners and anglers have reported loons taking bait, so it is a problem that anglers should be aware of. When loons are about, anglers should pull in the line and go elsewhere to fish.
The DNR is collecting any abandoned eggs and/or dead loons. If found, they should be put in plastic bags, frozen, and labeled with the information on where and how the specimen was found, then taken to the DNR office in Grand Marais. Local DNR wildlife manager Dave Ingebrigtson can be reached at 218-387-3034 with any questions or concerns.
Report submitted by Gunflint Trail Historical Society board member Phyllis Sherman.