I sometimes dwell on the negative. In fact, those who know me well no doubt would regard that as an understatement. Strangely, I myself forget that I possess this trait. As a result, I often careen downwards over periods of days or weeks, seeing one after another of the unpleasant aspects of a certain committee I sit on, a basketball team I watch, or a politician whom I hear speak. Eventually though, my negative jag launches me into something unambiguously positive that contradicts all earlier evidence and forces me to pause and reconsider.
So it has been in recent weeks, as I have worked on a team of loon biologists revising the common loon account for Birds of North America. While the long-term, downward trajectory of my study population had me in a funk, talking to and working with these folks (especially David Evers) has given me a broader, more balanced view of how loons are doing along the southern edge of the species range. This has turned me around.
As Dave pointed out to me, the picture of loon breeding in other parts of the U.S. is quite a bit rosier than in northern Wisconsin. While not all of the data are reliable, there seems no question that loons are thriving in Maine, New Hampshire, Vermont, and Massachusetts, having experienced double-digit increases in adult populations in the past decade. These findings contrast sharply with Upper Midwest loon populations, which have shown little or no change. In Minnesota and Michigan, according to our latest measures, populations are merely stable. Wisconsin loon populations, while they increased greatly during the 1980s, 1990s, and even early 2000s, have been measured as stable or declining in recent years.
So the overall picture of loon populations along the southern edge of the breeding range is mixed. But things look so good for the species in New England that, even after considering the slightly negative recent trend from the Upper Midwest, we must conclude that overall the U.S. loon population is doing fairly well.
The uneven geography of loon population patterns raises an important issue. Could the burgeoning New England loon population supply young adults that settle in the Upper Midwest, breed there, and thus rescue our struggling population? No, this cannot happen, because young loons do not disperse far from their natal lakes to breed. A few of the chicks that we have marked in Wisconsin have made it to Michigan, and one or two of these thousands probably has settled in Minnesota (though we have no reports to date), but none has gone farther afield than that. The stability of the Upper Midwest loon population relies solely upon the successful reproduction of Upper Midwest adults. In other words, we are on our own.
Still, the mere fact that loons are reproducing well and expanding their population somewhere is heartening. It suggests that factors causing the decline in the loon population in Wisconsin might be local ones, not sweeping ones, like climate change. Or it might mean that factors that could lead to loon population declines — whatever those factors are — can be reversed by intense local conservation efforts, such as occur in New England states.
At any rate, I am looking at the world a bit more cheerily now, after learning about thriving loon populations in New England. With my tunnel vision always focused more on things loon than things human, there is reason for hope.