For the past two decades most range maps for breeding common loons such as this have depicted a southern limit that cleanly bisects the central Lower Peninsula. In doing so, they have typically ignored a small, disjunct population of nesting pairs located well to the south in Barry and Allegan counties. Historical accounts for the area are comparatively abundant, and frequently as at right record the observation of breeding pairs and the simultaneous disruption of their nesting attempts. In spite of such disturbance, and of the immense pressure from residential development, a small bright spot in statewide surveying of the mid 1980s was the confirmation that a remnant assembly of common loons still summered in southern Michigan. By the end of the decade, however, further atlasing identified a sharp decline in their numbers; an attendant report offered a series of recommendations for maintaining the continuity of this reproductive outpost.
Shortly afterward, in 1992, the Michigan DNR’s Loon Recovery Plan attempted a similar assessment on a statewide level. The document divided Michigan into six regions, and assigned to each an estimated number of current breeding pairs and a future goal. In aggregate, they totaled 300 in the present and 575 as a long-term target for recovery. For the isolated southern population, the tallies were ten and fifteen pairs, respectively.
Twenty years later, one nesting pair remains. They inhabit Fair Lake, in southern Barry County, and represent not only the southernmost extension of breeding loons in Michigan, but in the world. Forty two degrees north, thirty five miles southeast of Grand Rapids, and more than seventy miles removed from their nearest neighbors. In their singularity they testify to the failure of the recovery plan’s ambitions for the southern region.
But what of the rest of the state? During the very same year that the plan was being assembled, additional surveying (again led by Bill Robinson of Northern Michigan University) revised the statewide estimate considerably upward, to nearly 500 breeding pairs. Further work at the end of the 1990s, organized through Lake Superior State University, suggested even higher numbers. And as of 2007, Common Coast has identified at least 500 current pairs in the Upper Peninsula alone, with an estimated 200-300 additional partnerships inhabiting lakes below the bridge. In the most straightforward interpretation of these findings, the overall numerical goal of the recovery plan has certainly been realized.
The manner in which this increase has been achieved, however, begs closer scrutiny. Are there now many more Michigan loons than in the 1980s, or have more simply been discovered? Our work on Isle Royale, described in detail here, provides a case study: after two decades of island surveying had consistently registered 40 or so breeding pairs, our own three-year atlasing effort ultimately documented over 100. While this 150% surge was a pleasant surprise, there was ample evidence to suggest that the overwhelming majority of it arose from an improved survey methodology, not an actual rise in loon occupancy. The same conclusion holds for comparable increases across the mainland Upper Peninsula resulting from CCRC atlasing. Such upward revisions would still be encouraging if not for the fact that UP sites such Isle Royale do not currently demonstrate measures of reproductive success to suggest that their levels are sustainable. We can best make inferences about this long-term viability by combining occupancy and productivity data with population parameters (juvenile survivorship and dispersal, adult longevity, etc.) gleaned from the study of color-marked loons. Isle Royale may currently be blessed with the highest density of loons in the state, but in order to determine whether it will still harbor 100 pairs in twenty or thirty years it is necessary to consider, for example, not only how many fledged juveniles leave the island every autumn, but how many of them are likely to return as breeding adults.
This intersection of monitoring and research a touchstone for Common Coast is ultimately more concerned with population trends than hard numbers. While our work at specific study sites has allowed us to draw conclusions about the state of affairs in those particular areas, it is not currently possible to make any authoritative statements concerning the present stability and long-term viability of the statewide loon population. We as an organization feel that addressing this deficiency would bear obvious benefit for matters of broad-based conservation, such as better illuminating the degree of peril posed by the current botulism outbreak on the Great Lakes. It would also, in our opinion, help to galvanize interest on local levels by providing individuals and associations with a context for their attempts to protect, assist or even reestablish loon pairs on specific lakes… that is, establishing a means by which their efforts are explicitly connected to those being undertaken on neighboring waterbodies, and throughout their region, and across the state.
As this notion relates to the southern limit of Michigan loons, in both 2006 and 2007 the Fair Lake pair who utilize an artificial nesting platform successfully hatched and fledged chicks. While the Fair male and female may maintain their partnership for another ten or twenty years, and could presupposing continued nesting assistance produce several dozen offspring during that time, the vagaries of juvenile survivorship and dispersal dictate little chance that the offspring of Fair Lake alone can recolonize the region the years to come. But if, seventy miles to the north, lakeowners and associations along the functional southern periphery begin to slowly encourage reoccupation on empty lakes through the deployment of platforms and the preservation of remaining habitat, then the long-term prospects for the region could tip slightly to the better. While we as an organization aren’t holding our collective breath for the recolonization of Oakland County, nor for the repopulation of all of the state’s Loon Lakes, we can credit the possibility of a breeding range that begins to demonstrably expand back into parts of southern Michigan. With success in this quarter, perhaps someday Fair Lake will, in a positive sense, be stripped of its notoriety.