The Cry of the Loon

An edited version of this article appeared in the Winter 2005/06 issue of ON Nature.

The first of several ironies in our relationship with the common loon is the way we’ve turned a vocalization born of stress—the multiple-note tremolo with an octave jump near the end—into an audio signature of northern tranquility. Loons make this call to defend their territory: to warn off other loons, birds, predators and humans who approach too closely. Too often, we have not listened to their warning signals, and then longed to hear that call again when lakes turn silent.

The common loon (Gavia immer) has been adopted widely by businesses, governments and organizations of all stripes whenever they have desired a symbol that conveys natural solitude and a ruggedly handsome wildness. It is the national bird of Canada (and hence is the “loonie” of the one-dollar coin), as well as the provincial bird of Ontario and the state bird of Minnesota. It is the focal point of Cottage Life magazine’s logo (not to mention the publication you’re holding in your hands). You can also find the loon’s profile in the logo of the Ontario Federation of Anglers and Hunters (OFAH).

The loon’s image is treasured by all sorts of groups that have not only some stake in its preservation, but (here comes another irony) some responsibility for its survival challenges. Waterfront property development is diminishing shoreline habitats the birds require; boat traffic is reducing reproductive viability by swamping nests with wake (and killing birds outright by running them over); and recreational angling gear has caused widespread, and fatal, lead poisoning in the birds. Another loon-related irony: OFAH has vociferously opposed federal proposals to greatly limit lead fishing gear that is poisoning loons and other water birds.

Is the loon an endangered species in Ontario? No—and on the surface of things, it’s doing quite well in most areas. With an estimated 232,800 adult loons in Ontario, and an estimated doubling of breeding pairs in north-central Ontario between 1991 and 2002, one well might wonder why we should even be giving loon numbers a moment’s thought in this province. Therein lies the next irony. For a bird so common that it is called “common,” there’s a surprising amount that we don’t know about it, at least in Canada. While the Canadian Loon Lakes Survey, a volunteer bird count project sponsored by the non-profit Bird Studies Canada, is striving to improve the data, general loon numbers in Canada still rely heavily on estimates from flyover inspections of remote lake habitats, not actual field counts. In other words, we haven’t built up the population picture from what scientists call “fine scale” data, gathered one verifiable bird or breeding pair at a time. “Our data on fine-scale populations is actually pretty poor,” says Craig Hebert, a research scientist with the National Wildlife Research Centre of the Canadian Wildlife Service (CWS) in Ottawa, who has studied the impact of botulism outbreaks in the Great Lakes on loons and other bird species. There are a lot of lakes where we believe loons are, but we don’t necessarily know for sure how many exactly. And even where we know they are, we don’t know how well they’re reproducing, or how many are dying, and why, in specific localities. But we do know that loons have long vanished from habitats in southern Ontario, where agriculture and urbanization have driven them out of their historic range. And, appropriate for a diving bird, it’s what may well be going on beneath the surface that should be giving pause.

We only have to look to the northeastern U.S. to appreciate what damage can be done to this striking and beloved bird, and how much work is involved to help its numbers recover, once they have been reduced. The experiences of American loon-recovery programs in Michigan, Vermont, New Hampshire, New York and Maine are eerily similar, and provide a forewarning of where Ontario could find itself headed with the loon. It’s as if, one day, people looked around their lakes in a particular state and wondered, where have all the loons gone? Didn’t we used to have more? 

Vermont found itself down to eight nesting pairs in 1983, and considerable effort has been required to raise that number above forty, a target the state has been able to meet since 2000. But Minnesota did not wait for its state bird’s population to free-fall before mounting a comprehensive study program, and it enjoys at least a ten-year head-start on Ontario in ensuring the longterm viability of loon numbers. Its Department of Natural Resources began monitoring population levels in 1994, on six hundred of the state’s more than 15,000 lakes. While populations have remained stable in the study areas over the past decade, the state has embraced the bird as an early warning system of overall environmental health, and has been able to draw a correlation between declining water quality (measured by increased turbidity) and significant reductions in some local loon numbers.

To understand why loon numbers can easily go south, you naturally have to understand the loon. It is not a garrulous bird that congregates in large flocks (except for migratory purposes) like geese or ducks. Studies in Minnesota, for example, have revealed an adult loon density ranging from about 0.5 to 4.5 adults per 100 acres of lake. Loons will kill rival loons (and other nesting waterfowl), spearing them with their sharp bill, to preserve their turf. “I’ve picked up three loons that were killed by other loons this year,” says Eric Hanson, a biologist with the Vermont Loon Recovery Project (VLRP), a joint undertaking of the Vermont Institute of Natural Science and the state’s Fish and Wildlife Department “They’re almost self-limiting.” And their reproductive rate is hardly prolific. You don’t find loons with a large brood paddling along behind mom. Research by Maine’s non-profit BioDiversity Research Group has determined that the average age at which loons begin breeding is seven, a long wait for an animal with a low reproductive rate. Breeding pairs usually produce one or two eggs around June, but the success rate for chicks is considerably less. Minnesota has found anywhere from 0.18 to 0.8 juvenile loons per adult loon in its study areas. Because they begin breeding at such a late age, and with so few offspring, any number of factors can seriously impact the stability of loon numbers.

Development pressures similar to the ones found in Ontario’s cottage country compelled the creation of the Michigan Loon Preservation Association in 1986 to carry forward the work initiated by the wildlife division of the state’s department of natural resources and other interested parties in the early 1980s. “As development moves north,” explains Arlene Westhoeven, the society’s president and an instructor in environmental biology at Ferris State University in Big Rapids, “you bring everything with it, including pollution and boats.” Indeed, one of Michigan’s biggest problems has been harassment of loons by personal watercraft operators who run down the birds for sport. But the most important factor in local declines, says Westhoeven, “is the destruction of nesting habitat. If the nest is gone, the loons will not come back to the lake.”

Avoiding disturbances of nests, which loons build along the shore only about three to six inches above the water surface, is key to reproductive viability, as the adults can be flushed off their egg clutch by boat wake, by curious humans who get too close, or by sudden changes in water levels caused by hydroelectric facilities. Educating waterfront property owners on how not to disturb nesting birds, and how to maintain natural shorelines, has been effective in the recoveries of stressed and extirpated populations. Boater education has also been critical. All may end up being strategies Ontario cottagers find themselves having to turn to.

The longer Westhoeven has worked on the loon’s recovery, the broader the problem has become. “It was perceived as human-loon conflict,” she says, something tackled on a lake-by-lake basis with good stewardship from volunteers practicing citizen science. “Then you find out about things like lead, pesticides, gillnetting, botulism. All of those things we have worked on as multiple causes for the decline in loons.” Her group’s goal is to have 500 nesting pairs in the state. An educated guess is that Michigan now has about 300.

Stress factors in loon numbers, as Westhoeven and others have learned, are multifold, but in Ontario the idea that human-driven changes in local lake environments might be seeding a loon population crisis isn’t particularly on the radar—although Cottage Life did address the threat to loon viability in 1999. The issues that have attracted the greatest attention in this province are lake acidification, botulism outbreaks and lead poisoning.

Acidification is a multiple threat. It harms fish populations on which the loon feeds, and is believed to be responsible for increasing the presence of mercury in the local ecosystem, which further harms fish and loon alike—in the case of loons by lowering their already low reproductive rate. In New York State, mercury is suspected of being a factor in a large number of loon deaths from aspergillosis, a fungal infection, as it is thought that mercury could be weakening the immune system.

Botulism crises on the Great Lakes have come and gone. The most recent one began in 1998, with large numbers of dead fish reported on Lake Erie. Outbreaks of type E botulism (first positively identified in Lake Erie in 1999) have since been witnessed on Lakes Huron, Erie and Ontario. The signal event for loon mortality was the fall 2002 migration. That November, 720 dead loons were counted at Long Point National Wildlife Area on Lake Erie—about thirty for every kilometre of shoreline.

Along with uncertainties about Ontario’s loon population we also don’t have a handle on migratory patterns for individual breeding areas. So, when migrating loons killed by botulism outbreaks began washing up, there was no way to know where the individual birds had come from, or were going. And there still isn’t, although scientists are hoping DNA analysis will begin providing answers.

We also don’t know exactly how they’re taking up the botulism. In 2005, there was a wobble in the standard pattern of birds dying during fall migrations, when large numbers of dead birds began turning up on Lake Ontario earlier in the summer. Nevertheless, the prime suspect has been an invasive fish species, the round goby. The theory goes that loons are eating gobies that have ingested the botulism by eating quagga mussels. “Botulism has always been there, but there has to have been a change in the way the toxin is being transferred through the food chain,” says Craig Hebert. “Maybe the gobies are playing some role. It’s all pretty speculative at this point. Botulism is something we’re going to have to live with. Unlike lead, which is something we do something about.”

It’s a critical point from a leading member of the avian scientific community, as angling groups opposed to proposed restrictions on lead fishing gear in Canada routinely argue that regulators are barking up the wrong tree with lead—that it’s botulism in particular, which is responsible for the documented deaths of thousands of loons, which should be the focus of attention.

Various bans on lead fishing tackle, overwhelming driven by studies of loon mortality, are now in place in Maine, New Hampshire, Vermont and New York. The movement to remove lead from fishing tackle in Canada has run up against one of the most strident counter-campaigns yet seen in environmental law in this country. No critic has been more vocal (or quotable) than C. Davison Ankney, a recently retired professor of zoology (avian and wildlife ecology) at the University of Western Ontario. Ankney is a leading proponent of the “botulism, not lead” argument, as he is quoted in OFAH’s February 8, 2005 submission to the federal government’s consultations on lead-free fishing, “unless CWS can show that lead sinker mortality is limiting the size of loon populations, they should turn their attention to something important instead of dithering about something trivial.”

Ankney has not stopped there. “In my 30 years as a wildlife scientist,” he has declared through OFAH, “I’ve seen bad science and I’ve seen abuse of science, but never have I seen so much bad science and abuse of science in one document,” referring to the CWS’s Occasional Paper 108 of 2003, in which CWS scientists addressed lead fishing sinkers and jigs and their toxic effects on the common loon. OFAH neglects to mention the fact that Ankney is a former OFAH president and currently is a member of its board of directors.

Vernon Thomas, professor of zoology at the University of Guelph, who was part of the outside peer review team on OP 108, readily fires back at Ankney’s categorization of lead toxicity in loons as “trivial.” An international expert on lead toxicity in birds who was influential in having the federal government institute a ban on the use of lead fishing gear in national parks in 1997, he adamantly states: “The problem is not trivial. When we look at causes of death in the North American population, what we’re seeing is that mortality from lead poisoning rivals any other type of mortality. We’re looking at 23–30 percent of adult loons in any sampling.” Numerous necropsy studies in Ontario and the northeastern U.S. back up Thomas’ claim. In fact, he’s probably being conservative. The latest results from the gold standard in loon toxicology, a study by the Tufts University School of Veterinary Medicine that’s been ongoing since 1987, attributes to lead toxicosis 35 percent of deaths among the 156 adult and immature birds recovered in freshwater New England lakes since 2001.

“The impact of botulism is obvious,” says Hebert. “It’s easy to count 1,000 dead loons on beaches. Lead is more insidious. You can have a fair amount of mortality in unpopulated areas, with nobody seeing the dead loons. I don’t think it’s fair to compare the two mortality issues.”

How many common loons in Ontario are actually dying of lead poisoning? To know that, you’d have be satisfied that we actually know how many loons there really are in this province, and also be satisfied that the small number of dead loons that are found every year (and having been turned in to authorities, are in a condition that allows a necropsy to be performed) represent a reasonable sample of mortality in the population overall. Nevertheless, the post-mortems performed on 134 adult loons carcasses recovered (outside of the botulism cases) in Ontario in the April–September period between 1989 and 2005 have produced death rates due to lead toxicosis in line with findings in similar U.S. studies. Necropsies conducted by the Canadian Cooperative Wildlife Health Centre (CCWHC) at the University of Guelph have determined that thirty-three of the recovered birds died of lead poisoning—the second highest cause of death after trauma (which includes collisions with boats, drowning in gill nets and gunshot wounds), at 43. That’s one in four recovered birds having died from ingesting lead. (Deaths from aspergillosis, which could be related to elevated mercury levels if the hunch of New York state researchers is correct, totaled 13.)

Doug Campbell, a staff pathologist with the CCWHC, says he is “pretty confident” of the link between death and lead ingestion in the thirty-three Ontario cases. “With the majority of them, you still find the lead present in the gizzard. The rest have detectable levels of lead in tissue at or above a level that would be sufficient to cause death. I think what happens with most of these birds, is they’re taking in lead sinkers with far more lead than you need to kill a bird. From the loon’s point of view, it’s a catastrophic event to pickup a single lead sinker.”

There’s been much debate about how loons ingest the lead. It’s long been believed that they scoop up loose lead shot and weights from the bottom for food grinding. But the bird’s propensity for swallowing fishing gear literally hook, line and sinker suggests that they’re mainly getting it by chasing live bait used by fishermen, and taking in the weight on the line, as well as weighted lures, in the process. A banding program in New Hampshire in the summer of 2005 produced impressive evidence of the loon’s ability to ingest—and endure—fishing tackle. The twenty birds captured were x-rayed as part of the tagging process, and eight were found to have fishing gear inside them. Only one of them appeared worse for wear. Provided a hook does not cause a fatal puncture, or a lure does not plug the esophagus, or fishing line avoids tying up the tongue, the strong acids in the bird’s stomach will erode the hooks and other metals. But if half an ounce of lead is attached to the line, there is more than enough toxin to kill the bird regardless. (That said, thirteen of the dead loons examined at the University of Guelph died from swallowing fishing gear. And 39 percent of the loons necropsied by Tufts since 2001 have shown a fishing gear injury above and beyond lead toxicosis.)

“Lead is a preventable problem,” says Hanson of the VLRP. “There are plenty of alternatives now.” Vermont’s 2004 legislation bans the sale of lead sinkers of one-half ounce or less beginning in 2006, with an outright ban on use to follow in 2007. A legislated free sinker exchange and education program began in 2004. “Education has made a huge difference here,” he explains. “We had almost no fight to stop it. People were realizing, ‘Hey, we have loons dying, and there are alternatives to lead gear.’ We introduced the sinker exchange program, and we got stores on board with alternative suppliers. People learned what the issue was, and that it wasn’t going to shut down everybody. People understand it, even if they don’t like it.”

•     •     •

Preserving the Loon: what you can do

•If you fish, get the lead out of your tackle box.

•If you own waterfront property, preserve your shoreline’s natural state to encourage nesting.

•If you’re a boater, mind your wake, as it will flush loons off their nests. Remember that the speed limit in Ontario is 10-k/h within 30 meters of shore

•Just because you see loons regularly on a lake doesn’t mean they have long-term viability locally. If you keep seeing adult loons without chicks, you might have a local population crash in the making.

•Give nesting loons plenty of privacy. They favour solitude, but in Vermont, loons have successfully reproduced on nests within five feet of a cottage dock, where property owners know to stay clear. And just because you’re in a canoe or kayak rather than a personal watercraft doesn’t mean you can come close to a nest without spooking the parents. Birds flushed off nests either don’t return at all, or stay away along enough for predators to eat the eggs or chicks.

•If loon numbers on your cottage lake concern you, speak with your local cottagers’ association, and consider beginning a monitoring and education program. In the U.S., recovery programs have been successful in using nesting rafts (where there is a lack of proper shoreline habitat) and buoys to keep boats clear of nesting areas. The Michigan Loon Preservation Association and its “loon ranger” volunteer program provide an excellent model of citizen-science stewardship. Go to to learn more.

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