In 1999, as part of an atlasing project on Isle Royale, we assessed Siskiwit Lake, the island’s largest inland body of water at 4150 acres. We delineated the lake’s loon territories, which were believed to number four or five, and identified nest sites in a non-disruptive manner. When finished, we had identified no less than nine breeding pairs on the lake, far and away the highest total in Michigan. As with the rest of the island, we provided park management with detailed maps of Siskiwit so that efforts could be initiated to minimize disturbance from both recreational paddlers and staff conducting future loon surveys. We also cautioned that the revised tally for island-wide occupation which, mirroring Siskiwit, had jumped dramatically as a result of our atlasing was not attended by a comparable increase in productivity, and as such the long-term stability of Isle Royale loons was uncertain. In other words: although you [the Park] have been largely effective in annually locating most of the island’s chicks, their number has represented the collective reproductive output of 100 total pairs, not 40, and if that pattern holds there’s good reason to believe that over time the breeding population will shrink.
We made several extended visits to Siskiwit over the course of the 1999 season, and in sum spent at least a week upon its waters… this for one lake. Based upon its size and seclusion, the logistics of atlasing Siskiwit were unusual, and strictly extrapolating the effort that it necessitated would be misleading. Nonetheless, there are thousands of lakes in Michigan that either harbor loons or, based upon of the demonstrations of habitat and history, should harbor them, and in aggregate they present a rather daunting hurdle of time and energy if each is to be addressed assiduously. In this sense, the notion of our small organization hewing to a “Michigan loons” philosophy feels like a prudently self-limiting exercise. It’s a big enough bite for us.
That said, there are exceptions and caveats. In the past we have been involved in a number of projects beyond Michigan borders, especially within the neighboring states and provinces of the Great Lakes region. More significantly, we believe that our work with loons can often apply itself to broader considerations and achievements in the arenas of research, education and conservation. For example, in engaging with lakeowners and associations to identify and develop shoreline easements, we are primarily interested in maintaining habitat for breeding loons, but in the process trust that the preservation of a riparian ecosystem will ultimately benefit a variety of species. Similarly, in attempting to heighten public awareness of the inconspicuous and often counterintuitive needs of nesting loons, we hope to foster something of a behavioral template that can be applied expansively and instinctively… an approach to the natural world that first asks is my appreciation of this setting incurring a cost to its inhabitants? In the case of a research topic such as mercury (Hg) contamination, we are interested in not only how loons are being impacted by their exposure to the toxic metal, but also in what their Hg levels can tell us regarding the threat posed to human consumers of fish from particular lakes, and what changes in these levels can suggest regarding the efficacy of curbing regional Hg emissions from coal-fired power plants and other significant polluters.
In light of these perspectives, probably the most accurate one-sentence answer is a small elaboration upon the precept of our home page: Common Coast is a non-profit organization dedicated to the study and protection of loons and the waters upon which they rely, especially within the Great Lakes region.
In spring I often see three or more adult loons on my lake in northern Wisconsin. For many years I assumed that this was the pair being joined by their young from the past summer, but it seems to happen even when there were no chicks in the year before. Also, sometimes things turn very violent, and end with the pair driving off the other loons, which doesn’t seem like a very nice way to deal with your kids. I’m wondering what’s really going on… are these birds not related to each other? ~ Mary G, Boulder Junction WI
As you’ve likely noticed, in years of successful reproduction the autumn departure of your lake’s loon family is not synchronous… usually mom goes first, dad follows a week or two later, and the chicks themselves are left to tackle their journey to the ocean without parental assistance. While the pair will likely return in the spring again, having migrated independent of one another their offspring, if they survive their arduous first winter, will remain on southern waters, and will not attempt the voyage north until they have reached maturity in their third (or, in rare instances, second) year. The intruders on your lake, then, are not last year’s young in search of parental assistance, but rather unpaired adults seeking to acquire a territory and because loons do not mate for life possibly a partner as well.
These challenges run the gamut of duration and antagonism. At times, a bird lands, engages in a few quick bill-dips and jerk-dives with the pair, and astutely determines that its efforts will be in vain… off it flies. But, as you’ve witnessed, other intrusions can manifest themselves as protracted engagements marked by extended sprints of “rowing” pursuit across the water, simultaneous point yodeling by two or more males, and moments of highly dangerous assault via bill or wing. Oftentimes the outcome is determined by the strength of the bond between the breeding pair, and detecting a successful usurpation can (in the absence of color-marked birds) prove difficult to the point of futility… it may seem as if a challenger has come and gone, when in fact a turnover in pairing has occurred, and the departing adult was actually last year’s resident male or female.
Among a pair’s offspring who do survive their multi-year adolescence on the ocean, it is males who are likelier to return as breeding adults to the area in which they were hatched; as with many bird species, returning females tend to disperse from their natal home at distances of thirty miles or more. At present there’s no evidence to suggest recognition between generations, an impression reinforced by the occasional, genetically-unwise pairing between mother and son.
Although spring carries with it the highest risk of territorial eviction, intrusions can take place throughout the breeding season, especially within healthy populations marked by a surplus of unpaired adults… see social gatherings for further discussion.