John James Audubon’s Double Crested Cormorant
The five men came ashore on Little Galloo Island, an uninhabited, 52-acre outpost on the American side of eastern Lake Ontario, on July 26, 1998 . The island was then owned by Phillips Petroleum and used for fall duck hunting, but as an Important Bird Area under New York state law, summer access for bird research was permitted by the company. These men, however, weren’t doing research, they weren’t from the oil business, and although they sported shotguns loaded with cheap shells that would not make much noise, they weren’t gunning for ducks out of season.
This story originally appeared (in an edited version) in the Winter 2002/03 issue of Seasons (now ON Nature). See also my 2019 Broadview article, “Cormorants Aren’t the Devil,” on the proposed hunt in Ontario that went into effect in September 2020, allowing hunters to kill as many as fifteen a day, with no season limit.
When they had finished littering the ground with about 130 spent casings, some 850 double-crested cormorants, most of them flightless juveniles, had been blasted to death in their nesting clutches. Another 100 were so badly injured that they had to be euthanized. It may have been the single worst slaughter in the United States of migratory birds protected by federal law. Certainly no one could think of a more dismal precedent. And it made people in the nearby summer community of Henderson Harbor cheer.
Many of its 3,700 residents were convinced the cormorants were destroying their livelihoods. The little port was heavily reliant on the local sportfishing industry, which in turn was heavily reliant on smallmouth bass. The fish had been in decline locally over the past decade, and data on fish populations and angling efforts didn’t suggest that the bass were being overfished by people. At the same time, cormorant numbers in eastern Lake Ontario had been exploding. In 1974, only 27 breeding pairs were counted on Little Galloo. In 1996, the number of active nests peaked at 8,410. Since 1992, half of the entire cormorant population on Lake Ontario had been crowded onto Little Galloo. New York’s Department of Environmental Conservation (DEC) had been using depredation permits issued by the U.S. Fish and Wildlife Service to destroy nests and eggs on several islands in the eastern basin, but not on Little Galloo, where it had launched a study of cormorant diet in 1998. It didn’t appear to require rocket science to connect more fish-eating birds with fewer smallmouth bass.
The vigilante action was far from isolated. The number of cormorant nests on False Ducks Island on the Canadian side of the lake’s eastern basin plummeted from 1,153 in 1998 to 153 in 1999 through illegal disturbances by persons unknown. And for decades, breeding colonies throughout the continental interior had been casually vandalized.
In recent years, Ontario has seen vociferous lobbying from hunters and anglers, native bands, municipalities, ratepayers groups and cottagers for a reduction of cormorant populations, either through culling by the Ministry of Natural Resources or the introduction of a hunting season. Among the cormorant’s alleged failings: its guano smells, destroys precious habitat, and pollutes water; it harbors Newcastle disease, which could threaten domestic poultry; and its nesting habits drive off other migratory birds. But make no mistake: the hot-button issue is the impact its diet may be having on sport fish.
Around Manitoulin Island in Lake Huron’s North Channel, the bird is suspected to be a major cause of the decline in yellow perch, although a 1999 Ministry of Natural Resources study of fish stocks on Manitoulin Island’s Lake Manitou exonorated the cormorant after suspicions of excess predation. Since 2000, Michael Brown, Liberal MPP for Algoma-Manitoulin, has been sponsoring a private members’ bill that amounts to a cormorant eradication program. It would make it legal not only to hunt cormorants during a controlled autumn season, but for any person “to destroy, take or possess the nest or eggs” without apparent supervision or limitations. (The most recent version, Bill 72, received first reading in June 2002.)
The Little Galloo slaughter has come to roost in Ontario. While it no doubt inspired the vigilante destruction of nests on Ontario’s False Ducks Island in 1999, the Little Galloo slaughter has also had a direct impact on the convictions of its lawful-minded, Canadian-based adversaries, as well as the province’s official approach to the cormorant population question. On December 18, 1998, the DEC announced preliminary results from its Little Galloo study, which actually blamed the cormorant for a decline in bass numbers. This could only reinforce anti-cormorant sentiments elsewhere in the Great Lakes. The DEC also announced that in “the near future” it would be meeting with Ontario’s Ministry of Natural Resources “to review the findings and discuss possible management options.” This led to the MNR’s announcement in May 2000 of a five-year cormorant study. This past summer, as part of that study, the MNR initiated a population control program within Brown’s riding, destroying thousands of eggs in the North Channel around Little Current.
We seem to have been despising this bird for as long as humankind has known it. And yet, despite eons of malice, and high present levels of anxiety, surprisingly little is actually known about how much this bird eats of what. Notwithstanding the DEC’s confident fingering of the cormorant in Lake Ontario’s eastern basin, no one has produced a credible, peer-reviewed scientific study linking cormorant numbers with declines in prize fish stocks on the Great Lakes.
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The bird is burdened by its own albatross, a poetic and literal reputation for greed and malice. In Book IV of Paradise Lost, the seventeenth-century English poet John Milton portrayed Satan as a cormorant perched in the Tree of Life in the Garden of Eden, “devising death / To them who lived.” It was an inspired transmogrification of Satan from his traditional Garden guise, a serpent, into a black bird with a serpentine neck and an established reputation for gluttony. It has been estimated that one double-crested cormorant consumes between one-quarter and one-half of a kilogram (one half to one pound) of fish a day, the equivalent of about twenty-five percent of its body weight. To its detractors, the cormorant indeed has been nothing less than the devil loose in Paradise.
It is hated in an impressive number of places worldwide. Recreational fishermen in Great Britain concerned about what they call the “black plague” even have their own web site: cormorantbusters.co.uk. Such is its dark reputation that a field guide could claim that it retreats to a cave at sundown, to hang upside-down by the four clawed toes of its webbed feet till dawn, and people would believe it.
There are between thirty and forty cormorant species worldwide (the taxonomy debate is ongoing), six of them in North America. They are all generally black, with a vaguely sinister profile, accentuated by a narrow, serrated and hooked upper bill so adept at grabbing fish. The double-crested cormorant, Phalacrocorax auritus —named for the tufts the males sport above their eyes during breeding season—has five subspecies; the most common, the “northern” variety, Phalacrocorax a. auritus, is the only cormorant frequenting the Great Lakes. An ungainly flyer, it nevertheless migrates from winter colonies in the Gulf of Mexico and Atlantic seaboard to breeding sites as far flung as western Idaho, northern Saskatchewan, and western Quebec.
Exactly when the double-crested cormorant started showing up on the Great Lakes is open to debate. Regardless, wildlife biologists do not consider it a foreign invader. “The cormorant is a native species in Canada,” Environment Canada firmly states in its fact sheet on the Great Lakes variety.
The bird’s historic role in native cultures suggests it has long used the Great Plains to the west of the Great Lakes, if not the lakes themselves, as a summer breeding area. Europeans first observed the cormorant breeding on Lake of the Woods in 1798, and one of the earliest definitive references to the bird in the Great Plains region was made in 1792 by the Hudson’s Bay Company’s chief surveyor, Philip Turnor, while travelling in northern Saskatchewan.
It’s possible that the double-crested cormorant’s summer range has moved into and out of the Great Lakes since prehistory, as breeding populations from the adjacent Great Plains and Atlantic regions expanded and contracted. Thomas McIlwraith’s 1886 Treatise on the Birds of Ontario called the cormorant an “occasional visitor,” and the 1895 edition of the American Ornithologists Union’s Checklist of Birds, an authoritative guide not given to casual observation, specified the Great Lakes as a cormorant breeding area. But the first Great Lakes nesting sites for the double-crested cormorant weren’t observed until 1913, on western Lake Superior. Population growth then spread roughly southeast through the Great Lakes basin, until the upper St. Lawrence was finally colonized about 1945.
The bird had scarcely set up shop on Lake Ontario when commercial fishermen began complaining in the 1950s that it was eating their catches. Official control measures were introduced in numerous jurisdictions, including Ontario, which were amplified by illegal culls and egg harvesting. At the same time, toxins such as DDE and PCB were likely causing eggshell thinning and reproductive failures. Throw in habitat loss, and the cormorant was doomed to suffer a severe population crash on the Great Lakes. Nesting pairs dropped from an estimated 900 in the early 1950s to just 125 in 1973. It had vanished altogether from lakes Michigan and Superior, was seriously depleted on Huron, and was down to ten pairs on Ontario. It became protected under the U.S. Migratory Bird Treaty Act when it was signed with Mexico in 1972, and many states and provinces extended it various levels of legislative sanctuary as well in the 1970s and 1980s. The double-crested cormorant is currently considered “not at risk” in Ontario, and is not protected under the provincial Endangered Species Act. But it cannot be hunted in any Canadian or American jurisdiction.
For a few brief years, this oft-despised bird was loved, at least by environmentalists. Pictures of double-crested cormorants with obscenely twisted bills, victims of toxic pollutants, were persuasive evidence of the need to clean up the Great Lakes. Successfully restoring cormorant numbers was widely viewed as a litmus test of an ecosystem’s recovery. When the remedial action plan for the cleanup of Hamilton Harbour was drawn up in 1991, a stated goal was to bring 200 nesting pairs of cormorants to Cootes Paradise, a sprawling wetland at the harbour’s west end. Yet, just five years later, such was the concern over the environmental impact of guano from cormorants nesting in trees on Hickory Island that flares were used in an unsuccessful attempt to scare them away. The cormorant has rebounded quickly, and some would say with a vengeance.
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Among the people in Henderson Harbor interviewed by National Public Radio’s “Living on Earth” program in the wake of the 1998 slaughter at Little Galloo was a charter fishing captain, Mitch Franz, who told NPR: “The bird is out of whack.” Franz said he’d been after New York’s Department of Environmental Conservation “for ten years now” to do something about the cormorants. “I think that the people around here probably have gotten fed up with the Department and the Fish and Wildlife Service and all the people who are from the Audubon Society and all the bird lovers’ societ[ies]. Yeah, they all love the birds. But the problem is, those people aren’t paying the bills.”
As it turned out, Franz was one of three Henderson Harbor fishing guides who, along with six other local men, would plead guilty in federal district court in Syracuse, New York, on April 8, 1999 to charges stemming from the slaughter. A tenth man was convicted of being an accessory to the killings, for hiding their guns for them. In all, some 2,000 birds had been illegally shot on the island that year by the convicted men. They paid fines of up to $2,500 and agreed to incarcerations ranging from probation to six months of in-home confinement. They also agreed to make a cumulative contribution of $27,500 to the National Fish and Wildlife Foundation, to be used in wetlands projects on Lake Ontario.
“I don’t know why the bird is so maligned,” confesses Linda Wires, a wildlife biologist at the University of Minnesota, as she considers the Little Galloo Island case and the unhappy reality that Collin Peterson, a congressman from her own state, has been pushing to make cormorant hunting legal. His legislative enthusiasm is shared by New York congressman John McHugh, whose district happens to include Henderson Harbor. “I’m almost going to give up on biology,” she adds. “Nobody’s listening. You present the biological evidence, and people say, `I don’t care. I know what those birds are doing.’”
Ms. Wires is the lead author of “Status of the Double-crested Cormorant (Phalacrocorax auritus) in North America,” aka the Wires report, a 377-page tome that compiled and critiqued everything known about the creature. Commissioned by the U.S. Fish and Wildlife Service, it was released by the University of Minnesota’s department of fisheries and wildlife in May 2001. The report provides, in part, a politely damning survey of the research performed to date on double-crested cormorant impact on fish populations. It found only one study, in the Les Cheneaux Islands of northern Michigan published in 1999, that was sufficiently rigorous in its methodologies to pass muster, and that study cleared them of blame for the local decline in yellow perch.
The Wires report also demolished the study of cormorants and their impact on smallmouth bass released in full in February 1999 by New York’s DEC, produced in association with the U.S. Geological Survey’s Biological Resources Division. It was researchers in this study who discovered the bloody aftermath of the shotgun slaughter on Little Galloo in the summer of 1998.
The New York study determined that smallmouth bass accounted for only about 1.5 percent of the local cormorant diet, with an annual consumption of 1.3 million fish. That’s actually not very many bass, as the local population measures in the billions. But because of what it determined to be heavy predation in some bass age classes, the DEC report said that there was “reasonable evidence to conclude that double-crested cormorant predation on smallmouth bass in New York waters of the eastern basin of Lake Ontario is excessive.” It was a groundbreaking study in blaming the cormorant for a measurable decline in a sport fish.
The report was released just as investigators of the Galloo massacre were able to link the guns used to their owners, and inadvertently helped turn the massacre’s perpetrators into local heroes. Fundraising dinners were organized by leading Henderson Harbor citizens to help pay the massacre participants’ fines and their compulsory wetlands contributions. Hats and t-shirts were sold.
Wires says the DEC study’s methodologies on diet and bass mortality “were not rigorous enough.” Deciding how many fish of a particular species a cormorant population eats by sorting bones in regurgitated pellets, as the DEC did, is fraught with uncertainty and error. The errors, says Wires, were compounded by using bass maturation and mortality rates gathered from a different time and place, Oneida Lake in upstate New York. Her report also cited a thorough study of smallmouth bass in the eastern basin by Canadian scientists from 1978 to 1998, which made a strong case that midsummer water temperatures were the major factor in bass population trends.
Wires is not blind to the possibility that cormorants could be affecting fish species in certain areas. Cornell University, she notes, is doing “really good work” on Oneida Lake, “and they’re finding that cormorants are having an impact on walleye and perch.” But she remains skeptical of many efforts to link cormorants to other environmental woes—crowding out black-crowned night herons at breeding sites, for example. Nesting site dynamics are complex, and she mentions a recent bit of field work in which she was able to disprove such an impact in a particular area. “We went out and recounted the black-crowned night herons. Most people don’t even know how to count them.”
Yet in Toronto, at Tommy Thompson Park, cormorant numbers have been controlled through egg oiling by the Metro Toronto Region Conservation Authority in order to preserve black-crowned night heron nesting sites. According to Bruce Pollard, a senior avian biologist with the MNR’s fish and wildlife branch,“It’s clear beyond a shadow of a doubt” that at this park at least, cormorant nesting was crowding out the herons.
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Bruce Pollard finds the cormorant controversy “an intriguing situation.” He defends the MNR’s study program, which has led to the destruction of thousands of cormorant eggs in Georgian Bay and the North Channel. “I think we’ve done a really good job of framing the questions,” he says. “We came up with a comprehensive list of data gaps.”
The MNR is conducting what is known as a “before-after control impact,” or BACI, study. The MNR first spent two years gathering population data on the birds and prey fish. They’re avoiding entirely the pellet surveys that caused so much controversy in the 1999 DEC study. “Cormorants eat pretty well whatever they get their beaks around,” he sums up. In year three, 2002, the MNR began oiling eggs to prevent them from hatching at selected cormorant breeding sites. Coating eggs with oil is preferred to physically destroying them, because cormorants have tended to react to smashed eggs by flying to a new colony area and laying a fresh clutch.
If the cormorants are having a deleterious impact on certain fish species, then reducing the bird’s numbers, holds the logic of the study, should show positive changes in species data. Seven separate study areas were established in Georgian Bay and the North Channel, and oiling has gone on in three of them.
Drawing solid conclusions about interactions between cormorants and fish populations is not going to be simple. “There’s a huge amount of variability in natural systems,” Pollard acknowledges. He also recognizes that two of the cormorant’s favourite fish, the alewifeand the rainbow smelt, are non-native to the Great Lakes, and that it’s very likely that their proliferation in the twentieth century encouraged the spread of the cormorant. This raises concerns that if cormorant numbers are seriously reduced to placate fishermen, unchecked population growth in alewives and smelt could reverberate catastrophically through the ecosystem. “We view these birds as an important pat of the ecosystem, and we don’t want to see them disappear from it,” Pollard emphasizes. Cormorant numbers have also probably increased in the Great Lakes because of new food resources provided by aquaculture operations in their wintering grounds. Aquaculture workers in the southern U.S. are permitted to shoot cormorants on sight. “We cannot turn the Great Lakes back to the turn of the previous century,” he notes.
Jerry Ouellette, Ontario’s minister of natural resources, emphasizes the importance of developing “the management strategies necessary for the birds.…We’re trying to assess it and proceed in a logical and scientific fashion.”
When this writer mentioned to the minister that he lives on southern Georgian Bay and keeps a boat at the north end of the bay, Ouellette replied, “Oh, so you know the problem up there.”
But the problem, it seems, is that we don’t yet know if there really is a problem. —Douglas Hunter