By STEVEN MAIER
Capital News Service
LANSING — Culling season is coming quickly for a controversial Great Lakes waterfowl after it received a one-year reprieve.
Control of the double-crested cormorant will return this spring when the bird returns from wintering along the Pacific, Atlantic or Gulf coasts, according to federal authorities.
Almost all culling was suspended last year after a federal judge ruled in May 2016 that the U.S. Fish and Wildlife Service had failed to adequately assess its impact. With that study complete, the agency can again issue permits to kill cormorants to protect property, habitat, airports, fish hatcheries and other birds.
“We’re trying to balance maintaining a stable cormorant population with managing them in the place where they’re causing damage,” said Tom Cooper, a program chief for the agency’s Migratory Bird Program.
The agency will issue permits to kill up to 18,270 cormorants this year in eight Midwestern states.
Permit applicants must submit photos of cormorant damage, how many cormorants they wish to kill and how they plan to do it, Cooper said.
Cormorants moved into Michigan from neighboring states in the early 1970s, according to a Department of National Resources report. By the turn of the century, there were 30,000 nesting pairs in the state.
Their colonies are found in places like Beaver Island in northern Lake Michigan, Ludington and the Les Cheneaux Islands just off of the southeastern edge of the Upper Peninsula.
Some area residents claim the birds hurt local fisheries but researchers say the cormorants’ impact on local fishing is exaggerated. In fact, scientists have discovered that cormorants are eating invasive species, especially round goby in Lake Huron’s Saginaw Bay and Lake Michigan’s Beaver Archipelago.
Once threatened by chemical contamination, the birds have returned in dramatic numbers.
There were only 125 nesting pairs of Great Lakes cormorants in 1972. Today, there are 40,000 pairs, and they’re causing a big problem on many islands where colonies have degraded many habitats, forcing other animals to move on.
Anglers know them as the bird whose numbers blew up in the 1980s after tapping into a nearly bottomless supply of the invasive alewife. They’re incredible divers and can eat one-fourth of their weight in fish each day.
And they’re public enemy number one for many perch anglers, although how many perch they eat is hotly debated, Cooper said.
Many know them by a distinct calling card — acidic feces that damages cars and buildings. They also destroy vegetation, stripping trees of leaves for their nests and poisoning the ground with their guano.
But defenders think of them as a bird that’s faced persecution for centuries and continues to do so despite protections t under the Migratory Bird Treaty Act of 1918. Some remember them as an environmentalists’ poster child — their DDT-malformed beaks were displayed on posters. The deformities caused by that insecticide kept them from eating and reproducing, threatening the bird’s existence.
Cormorant management is contentious, Cooper said.
“There’s folks that are on both sides of the issue,” he said. “Our role is to balance those using the best available information.”
The Fish and Wildlife Service began to allow culls in 2003 after mounting complaints of damage by a booming cormorant population. Cormorants threatening fish hatcheries, vegetation and other birds were often taken without a permit.
The birds were either harassed or shot, but many prefered to coat their eggs in oil, asphyxiating the embryos. Cormorant mothers continue to sit on the dead eggs. The mothers otherwise often laid new eggs if they found theirs were smashed.
Cormorant management is often done to protect shorebirds that often live alongside the colonies, but researchers at the University of Minnesota found that the culls hurt some of those same species.
The team analyzed population data from 1976 to 2010 and watched how the colonies fared when cormorants were killed.
Black-crowned night herons nest in the undergrowth, often under cormorant nests, said Francie Cuthbert, a co-author of the study in the “Journal of Wildlife Management.” Culling cormorants should save their habitat from an acidic demise and boost the heron population. Instead, those populations declined when the cormorants were killed.
Egg spraying is probably the culprit, she said. To spray cormorant eggs, managers must traverse the island, causing panicked heron chicks to fall out of their nests. The parents then no longer care for them and they die.
For two species of gulls, the opposite is true. The Great Lakes have too many gulls already, and cormorant management makes it worse, Cuthbert said. Gulls raid empty cormorant nests — an easy-access, population-boosting food source.
“When somebody goes in to spray the eggs, the cormorants are the first to take off, and boom, they’re gone,” Cuthbert said. “They’re out sitting on the lake.”
Gulls are quick to take advantage, she said. “They’re into that cormorant colony, busting open eggs as fast as they can.”
That makes for more gulls, and another possible round of eggs from the cormorant mothers, she said.
Cooper said the Fish and Wildlife Service is aware of the study. The managers he’s spoken with are open to changing tactics, even if it means hampering efficiency by limiting egg oiling.
There were close to 10,000 cormorant pairs on West Sister Island in Lake Erie before culling started in 2006, said Jason Lewis, the manager of the Ottawa National Wildlife Refuge in Ohio. The island’s colony has since been cut to 4,000 pairs.
Other nesting species on the island were struggling as the number of cormorants continued to grow, Lewis said. And West Sister Island is the only habitat of its kind in the western basin of Lake Erie.
“It’s not like these species have any place to go,” he said.
Since culling began, vegetation and co-nesters on the island have bounced back, Lewis said.
Steven Maier writes for Great Lakes Echo.
By STEVEN MAIER