They often have a pair of shaggy tufts -– double crests -– on their heads that make them look like disheveled professors. They nest in colonies, and sing in grunts that sound more like the calls of pigs or toads than birds.
Around the Chesapeake Bay, you may have seen cormorants standing on pilings in their trademark pose: with their black wings held out sideways, to dry in the sun.
It is this vampire-like posture –- and the fact that cormorants eat fish -– that has made the birds hated by fishermen and misunderstood for centuries. Long a symbol of bad luck and evil in Western literature and myth, cormorants have been persecuted and slaughtered by fishermen and even governments, according to a new book called The Devil’s Cormorant by Richard J. King.
“It’s really interesting to see how far back it goes, this sort of anti-cormorant feeling in literature and art,” King said in an interview. “Milton famously had Satan sitting like a cormorant on the tree of life. Shakespeare uses cormorant imagery four times in his plays. And in Shakespeare’s time, being ‘cormorous’ meant being greedy or insatiable.”
Despite the bad rap in Western culture, cormorants are miraculous in their own way. They can migrate thousands of miles, swim deep beneath the water with their webbed feet, and are trained like pets in Japan and China. In these countries, people fasten rings around the necks of cormorants, and attach long leashes to them, and the birds dive own into the water and retrieve fish for their owners.
Even more amazing is the comeback story of cormorants. After being nearly wiped out in many areas, cormorants started multiplying in the 1970s in the United States because the federal government banned the pesticide DDT and outlawed the shooting of cormorants in 1972.
There were no nesting pairs of cormorants in Maryland in the 1970s, according to the Maryland Department of Natural Resources. But by 1990, there were 55. And today, there are about 4,000 nesting pairs here, according to David Brinker, a wildlife biologist with the state agency.
The Virgnia-based Center for Conservation Biology reports that Virginia had zero nesting pairs of cormorants until 1978, when six pairs were discovered on the James River near Hopewell. Today, the center estimates there are more than 5,000 breeding pairs throughout the Chesapeake Bay.
“I view cormorants as a good sign,” Brinker said. “Here’s a new species that adds to the diversity of the fish and wildlife populations of the state of Maryland.”
Double crested cormorants have long migrated through the Chesapeake Bay in the spring and fall, as they moved between their nesting grounds in New England and their wintering areas in Florida and the Gulf of Mexico. Biologists say the nesting has apparently spread south from New England, as the bird population has grown. But whether cormorants ever nested in the Chesapeake Bay in the past is a matter of dispute.
King’s book documents a writer from 1610, who observed cormorants in Virginia’s rivers “in such abundance as are not in all the world to be equaled.”
Bryan D. Watts, Director of the Center for Conservation Biology, said it is “absolutely possible” that cormorants nested in the Chesapeake Bay hundreds of years ago, before being killed out and driven off.
“Many waterbirds have expanded and contracted their ranges up and down the Atlantic Coast in recent decades," Watts wrote in an email. "So there is no reason to believe that cormorants couldn't have done that several times in the past."
There are some nuisance issues associated with cormorants, because they are a colonial breeder. And they sometimes nest in places that are inconvenient to people.
“Cormorants have taken to nesting on the Bay Bridge,” Brinker said. “And what happens then is that any chickens born on the bridge think, ‘oh, home is a steel girder with all this traffic zooming overhead.’ So when they become adults and try to find nesting sites, they will find places similar to where they were raised. So they will try to find bridges. Letting them continue to nest in places like that just makes the nuisance issue worse.”
Cormorants (like other colonial birds) also tend to nest in such densities that their waste kills grasses and trees on parts of the islands they occupy. They eat about a pound of fish a day -– but not enough to harm overall fish populations or the fishing industry, scientists say.
Nevertheless, the U.S. Fish and Wildlife Service in 2013 intentionally destroyed about 3,200 cormorant eggs on Popular Island in the Chesapeake Bay.
Peter McGowan, a wildlife biologist with federal agency, said he and his colleagues sprayed a portion of the colony’s eggs with vegetable oil, which suffocates the embryos. He said wildlife managers worry the booming cormorant population would crowd out other, more threatened birds. Common terns, glossy ibises, and snowy egrets are competing with the cormorants for nesting space, McGowan said.
“There are other species that are –- I wouldn’t’ say have preference, but they utilize habitats that are quickly being lost in the Chesapeake Bay,” McGowan said “And we need to focus on trying to provide the nesting habitat for those species, otherwise we are going to lose those birds from the Chesapeake Bay.”
Stephanie Boyles Griffin, a director at Humane Society of the United States, said the destruction of cormorant eggs is inappropriate –- and an example of how they are still being unfairly discriminated against and persecuted.
“The Humane Society of the United States is strongly opposed to any lethal efforts to control cormorants,” Griffin said. “They’re a native bird. The reason that fishermen and wildlife managers want to manage them at all, using lethal or nonlethal methods, is because of land-use decisions that we as humans have made. We have taken up residence most of the coastal areas of the Chesapeake Bay, and this is all colonial nesting and shorebird breeding ground.”
Development and rising sea levels driven by climate change are forcing common terns and other birds to compete with cormorants for a shrinking number of secluded waterfront nesting sites. People are trying to pick the winners and losers in this competition -- with a misunderstood black bird paying a fatal price.
By Tom Pelton
Chesapeake Bay Foundation
By Tom Pelton
Chesapaeke Bay Foundation