Not a Terrible Breeding Year

Yes, it has come to this. Chick production of breeding pairs in northern Wisconsin has declined steadily during the past quarter-century. Black fly outbreaks have made hatching success even worse in the past five years. So we are searching desperately for a positive outcome that we can greet with a sigh of relief. And we have one: breeding success has ticked slightly upwards in 2021.

I wish I could report that breeding success has rebounded with a vengeance. After a dreadful 2020, I felt that a strong rebound might be in order. But the recovery has been modest. Looking at the numbers, only three breeding pairs in our study area had chicks as of this date in 2020. That laughably low number resulted from 97% abandonment rate of May 2020 nesting attempts owing to black flies. Meanwhile 59 pairs were incubating eggs on this date in 2020. As of August of last year, 36 pairs were rearing chicks. This amounts to about 33% chick production in 2020 (36 of 110 breeding pairs). At present, we have 24 pairs in Wisconsin raising chicks and 41 other pairs still sitting on eggs. If we use the 2020 nesting outcomes to project 2021 success, we should end up this year with roughly 46 of 110 pairs with chicks in northern Wisconsin. A 42% breeding success rate is nothing to crow about. But since I am a positive person, I will choose to focus instead on the 28% increase in chick production between last and this year!

What about Minnesota? We have only just arrived in Minnesota and have no data from 2020. So we are not able to provide a very calibrated picture of breeding success in the Crosslake area, where we are located. Furthermore, Crow Wing County, where we work, is running about a week behind Wisconsin, so our data are even more preliminary in Minnesota than in Wisconsin. Still, we can already say that 2021 was a light black fly year in north-central Minnesota, as it was in northern Wisconsin. And that is a good thing. Out of 104 territorial pairs we are currently following in the Crosslake area, Jordana and Katy reported a few days ago that 13 have chicks and 42 are on nests. We estimate that the total pairs with chicks will number about 40, by the time August rolls around. But we are still scouting many of our Minnesota lakes, so that number could grow to 50.

Scouting new lakes is a tricky business, by the way. Going onto a new lake with no information on previous loon usage or breeding success forces you to read the behavior of loons on the lake to infer if those you see are: 1) an established pair that has is not currently incubating eggs, 2) a pair that hangs out together but never breeds, 3) an unpaired young floater, or 4) the “off-nest” member of a pair, whose mate is on a nest on the lake. Katy and Jordana’s daily sleuthing has been effective so far. But sometimes you misread the signs, which, in fact, can be thrilling. No doubt a few lakes where K and J found no loon or only a skittish loner on their first visit will offer a view like that in Linda’s photo on their second.