I am far behind schedule. Just as I am preparing to report which of our marked loons returned, the loons themselves have hatched chicks. While I am pondering which loons survived the winter and settled on their previous territories, the loons are busy warning foreign adults with yodels to keep them at a distance, wailing like banshees at eagles overhead, and overreacting vocally to every mildly threatening muskrat, osprey, or great blue heron that ventures close to their little ones.
But it cannot be helped. I am in the midst of a book and jealous of every moment not spent writing it.
However, I have not completely forsaken fieldwork for the printed page. I took the month of May off from my project to race around our study areas in Minnesota and Wisconsin and train the new Minnesota team. And I have now tallied the banded loons that we resighted. This is my report from that field effort.
In Wisconsin, 52 of 70 banded males returned to the territory they occupied in 2025, and 51 of 66 females did so. In Minnesota, 65 of 71 males returned, and 61 of 68 females came back. The proportions returning are shown below.
These differences look pretty stark. But before you jump to conclusions about them — perhaps making a hasty comment about your neighbors that you will later regret — let me explain them a bit. The Minnesota numbers are solid. We spent ample time at each of these territories and have observed each on at least three separate occasions to ensure that we did not miss any loons and that our visit did not coincide with a social call by the breeding pair to a different lake nearby. On the other hand, the Wisconsin return rates for both males and females are biased downwards — are too low, in other words — because we certainly missed a few loons that happened not to be present on the day of our single visit to their lake. Remember, we were all out to cover the Wisconsin territories this year and currently have no regular team in that study area.
Some of the strikingly low return rate in Wisconsin can be explained by the curious spate of tragic deaths that occurred there in 2025 — the South Two female, North Two male, Jersey City-Flowage male, for example. Still, I don’t like the look of the Wisconsin returns. In addition to the banded birds that we failed to relocate, several of our regular territories that have always supported pairs — Hancock, Oneida-East, Carrol, Greenbass, Coon, Thunder, Hilts, and Wind Pudding — were either devoid of loons or occupied by a lone adult at the time of our visit. Pairs have no doubt settled on some of these lakes since we stopped by to look, but others, I am confident, remain without a pair. A worry-wart like me cannot help being concerned that our recent field work in Wisconsin showed us a pattern that I have feared since first documenting the steep downward trend in young adult survival five years ago — the leading edge of population decline.
* The featured photo depicts the 12-year-old male breeding male of Gilmore Lake in Wisconsin sitting on his 2026 nest. Hatched and reared on nearby Hasbrook Lake, this male and his mate have fledged seven chicks over the past six years.