A Brief History of Loons and Loon Management in Michigan
By William L. Robinson
Professor Emeritus, Northern Michigan University
from Loon Echoes, Dec 1999
W.B. Barrows, in his classic 1912 book, Birds of Michigan, noted that Common Loons (Gavia Immer) occurred throughout the state, but by the early 1900s had largely disappeared from southeastern Michigan. By the early 1980s, surveys sponsored by the Michigan Nongame Wildlife Fund, the North American Loon Fund, and the newly formed Michigan Loon Preservation Association and conducted by the Michigan Department of Natural Resources and cooperating university biologists revealed that there were fewer than a dozen nesting pairs in the southern half of the lower Peninsula, and that loons appeared to be declining seriously in the northern Lower Peninsula and some parts of the Upper Peninsula, as well.
Reasons for the declines were not definitely known, but it appeared that various human activities were responsible. Such activities included disturbances of loons on their nests and in their brood rearing sites, entrapment of adult loons in commercial traps nets set for whitefish, and occasionally outbreaks of botulism (mainly on Lake Michigan). The Common Loon was designated as threatened in Michigan, and in accord with the Endangered Species Act, a committee of state, federal, and university biologists developed a recovery plan. The plan required making surveys of lakes throughout the state to get an estimate of the numbers of breeding loons present, their reproductive success, to determine causes for low numbers of loons, and to recommend actions to increase their numbers.
Unlike other waterfowl such as ducks, which begin to breed with they are one year old, and produce a clutch of 8 to 12 eggs, loons do not breed until they are least three years old, and they lay only one or two eggs (rarely three). Therefore, loons, like eagles and condors, are unable to replenish their numbers in a short time. Loons are superbly adapted for an aquatic existence, with their large webbed feet placed far back on their bodies, but this adaptation makes it very difficult for them to move about on land. Thus they must build their nests close to the water or risk being killed and eaten by raccoons, coyotes, wolves and otters. This reproductive behavior evolved through the millennia, before humans invented powerboats and other wake-generating water toys, and before lakeshores were lined with cottages and mowed lawns.
Any watercraft that generates a wake of more than six inches high may destroy loon eggs. Sometimes loons will attempt to replace a lost clutch of eggs, by re-nesting nearby, but if no protection from boat wakes is available, the second nest will also be destroyed. A few waves from a single watercraft can, in a few seconds, destroy a nest and probably an entire year’s reproduction of loons. Even without creating a wake, a fisherman innocently anchored near a Loon nest in May or June, may keep a Loon off her eggs, causing embryos to bake and die in the sun. Other boaters, fascinated and amused by the spectacular displays and calls of parent loons distracting intruders from their young, have been known to pursue parent loons until they die of exhaustion. These factors, researchers believe, are the primary reasons for declines in Loon populations where humans have invaded their breeding range.
To protect the loons from both intentional and unintentional harassment by humans, interested citizens formed the Michigan Loon Preservation Association (MLPA) in the early 1980s. Its primary goals were to educate the public about the threatened status of loons in Michigan and to support research to enhance environmental conditions for loons so that their populations would be secure. One of the programs of MLPA, referred to as Michigan Loonwatch, involved designating a local volunteer (referred to as a " Loon Ranger") whose responsibility was to monitor loons on a lake, usually one on which they owned property, to report on nesting and reacting of young loons, and perhaps most significantly, to educate all other users of the lake about loons and their vulnerability to intrusions. These people took their job seriously.
One of the causes of deaths of loons has been drowning in commercial trap nets set for whitefish in the Great Lakes. After the nesting season, many loons which have occupied inland lakes visit the Great Lakes to feed on fish that they can find readily in the clear waters. The Department of Natural Resources, in the 1980s, estimated that about 260 loons were drowned annually in commercial fishing nets in Michigan waters, with 86 percent of those in trap nets. (The estimated number of breeding loons in Michigan is only somewhat over 400) Loons apparently are attracted to fish trapped in the 20x20x20 foot "pot" of the trap net and drown when they attempt to surface and become entangled in the mesh of its roof. Traditionally, the roof of the net consisted of 4x4 inch nylon mesh.
Research conducted in 1990 by NMU graduate student, Corinne Carey, sponsored by MLPA and DNR, using temporarily captive loons, revealed that most loons could pass through a 6 by 6 inch mesh. In the early 1990s, graduate student Joe Christiansen, with the cooperation of commercial fishermen, monitored trap net lifts. He found that under pressure from the Michigan DNR, most commercial fishermen had converted their nets to the 6 by 6 in. mesh. Following such adoption, the estimated seasonal Loon catch on Lake Superior was reduced from an estimated 263 to 77 loons. Fishermen who have converted the tops of their nets to the larger mesh found no significant reduction in fish catch, as the whitefish instinctively tend to go deeper when in trouble, thereby remaining in the pot to be harvested.
The goal of the Michigan Loon Recovery Plan is to maintain at least 575 breeding pairs, and to sustain such a number for at least five years. Goals of breeding pairs are established for six regions as follows:
Isle Royale-40: Western UP. –200; Central UP.- 200; Eastern UP-100; Northern LP-150: and Southern LP-15. According to surveys made every five years, supported by the Michigan Nongame Wildlife Fund, the North American Loon Fund, and the Michigan Loon Preservation Association, breeding Loon populations in the northern Lower Peninsula in 1996 consisted of an estimated 177 pairs. This was above the goal of 150 breeding pairs for that region established by the Michigan Loon Recovery Plan. (That region was the only major Loon breeding region in the state to exceed its goal) This area of the state was also the area in which the "Loon Ranger" program was most active. Despite the fact that humans more heavily populate lakes in this part of the state than those in the Upper Peninsula, Loon nesting success was higher. It appears that the efforts of the "loon Rangers" have been very effective. One might even suggest that without their enthusiasm, conscientious work, and vigilance, loons might be approaching extinction in the Lower Peninsula.
Flaws in estimating the number of loons in Michigan have occurred in most surveys because of the vast number of lakes (11,000 plus) in Michigan and the difficulties of obtaining a random sample large enough to be representative of the entire state. The 1996 season was characterized by an extremely cold spring with ice remaining on many Northern Lakes into late May and early June probably causing stress for loons and reducing their nesting success, especially in the Upper Peninsula. Surveys done only every five years furthermore run the risk of an unusually late or dry spring, thereby introducing a variable not easily rectified. Other states have employed aerial surveys to count broods of loons with some success, and this may be adopted in Michigan. Researchers from Lake Superior State University, advised by Dr. William Bowerman of Clemson University, are attempting to improve sampling methods to obtain better estimates of breeding loons in the state.
In summary, research supported by the Nongame Wildlife Fund of the Michigan Department Natural Resources, the North American Loon Fund, Michigan universities, and the Michigan Loon Preservation Association has identified and documented the causes for low Loon numbers. The application of results, through public education, has been effective in at least stemming the decline of loons throughout most of state; although only in one portion of the state, the Northern Lower Peninsula, have significant increases in Loon numbers occurred. New approaches such as aerial surveys of breeding loons appear to have considerable promise in increasing the efficiency of the surveys.