On the Loon Project, we are all out to band loons in Minnesota. This effort borders on obsession. Since adult loons must produce chicks to be easily catchable, our marking initiative depends upon finding pairs with chicks. “Have you seen any loon nests on your lake?” is a refrain Eric Andrews and I uttered to many residents of lakes in Crow Wing and Cass Counties back in May and June. “Have you seen any chicks?”, I have begun to ask in recent days, now that I am on my second tour through the Minnesota Study Area. This question is on my lips so often that I now smile inwardly each time I ask it. I hope that I do not sound desperate.
People have been happy to answer our loon-related questions. Driven by love of the state bird, scores of Minnesotans have shared their observations of loons, nests, and chicks, given us permission to launch canoes from their property, and even permitted us to post their photos of loons to spruce up our blog and Instagram posts. (Sheila Farrell Johnston’s cool photo, above, of a territorial battle on Upper Gull Lake this spring is a case in point.) Minnesotans, it seems, are as concerned about loons as we are and wish to help us enhance the current low-resolution picture of the state loon population with a robust, scientific analysis. The outpouring of support we have received this summer has ended any lingering uncertainty we had about continuing our research in the region. *
A growing demographic disparity lends urgency to our efforts in Minnesota. You see, accumulation of data from the Minnesota Study Population — and comparison with corresponding data from Wisconsin — has revealed that loons are returning to their territories at a lower rate in Minnesota than in Wisconsin. That’s right. In Wisconsin, where we already know the population is in some trouble, adult loons are returning to their territories at a higher rate than in Minnesota.
The numbers speak for themselves. In 2023, 63 of 74 Wisconsin territorial females (85%) returned to their 2022 territories, while 69 of 79 Wisconsin males came back (87%). Those numbers are typical for Wisconsin and for New England loon populations as well. In contrast, only 81% of Minnesota females (34 of 42) and 82% of Minnesota males (37 of 45) returned in May 2023 to the territories they owned in 2022. Now, these are not massive samples. So you might be excused for dismissing these numbers as sampling error from which no conclusion can be drawn. But this is the third independent analysis that has shown a higher rate of return in Wisconsin. We saw the same story in the data from last year and from Kevin Kenow’s marked adults from 2015-2017. So the time for hemming and hawing is over. We can no longer escape the fact that loons in Crow Wing County are returning to their territories less often than loons in Oneida County, Wisconsin.
Before you hurl yourself off of your dock, let me add some perspective. The lower return rate in Minnesota does not necessarily indicate lower survival there. Why not? Because a loon’s ability to return to its previous territory depends not only upon its being alive, but also upon its ability to defend its territory from challengers. Minnesota loons might be surviving just as well as — or even better than — Wisconsin loons. If so, however, they are being evicted from their territories at an astonishingly high rate.
Paradoxically, a high rate of eviction in Minnesota, if it is occurring, could be good news. A high eviction rate might indicate that Crow Wing County is overflowing with young 4-, 5-, and 6-year old adults looking to challenge owners for territories. If so, frequent eviction reflects high breeding success of loons in the County (4 to 6 years ago), because it is Crow Wing County loon pairs (for the most part) that have placed all of these young whippersnappers into circulation.
Ok, I admit it. I am putting lipstick on a pig. I do not truly believe that our Minnesota loons are kicking each other off of territories often enough to account for the low return rate we have found there. I do not know how to account for the pattern. But I am yet not unduly concerned about our Minnesota Study Population. Adult survival, even if lower in Minnesota, is only one piece of the puzzle. Still, the news is pushing me to be even more inquisitive of Minnesota lake residents. Someone listening closely late this afternoon might have heard my favorite question echo across the gently scalloped surface of Duck Lake: “Have you seen any loon chicks this year?”
*Mind you, we are still enthusiastically following our long-term study population in northern Wisconsin. Wisconsin loons continue to yield exciting insights about age-related behavior patterns and impacts of water clarity on the health and survival of loon chicks.