A baffled scientist hunts for the cause of a mysterious mutation that is distorting beaks of Washington’s birds of prey

MOUNT VERNON, Wash. — It took some effort for Bud Anderson, a falcon researcher in Bow, to pull the dead red-tailed hawk out of a tree on the Samish Flats. The freezing weather and the bird’s rigor mortis had wrapped it around a branch.

Anderson climbed about 5 feet off the ground. He reached out with his bare hands and pulled the bird free, dropping it to the snow on the ground. The first place he studied was the bird’s beak.

The top half of the beak had already rotted and fallen off, but looking at the lower half, Anderson saw a familiar deformity that might have led to the bird’s death.

For the past two years, Anderson’s organization, the Falcon Research Group, has documented a mysterious disorder among an alarming number of hawks in western Washington.

The disorder causes the birds’ beaks to grow faster than normal and makes it harder for the hawks to hunt. In some cases, the deformity has developed to such an extent that the birds are unable to eat, leaving them to slowly starve to death.

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Reports of the disorder in hawks range from British Columbia to central California and include four different species of hawks.

Unconfirmed cases of the disorder have been reported in Los Angeles, Texas and Minnesota and include crows and common seagulls.

The cause of the disorder, whether it is tied to pollution or to a disease, is unknown.

For now, there are more questions than answers.

If the hawk Anderson found dead in the tree last week is determined to suffer from the disorder, it will be the 60th instance of the deformity since Anderson first saw a long-billed hawk in 1997.

Anderson said he is convinced the 59 confirmed cases are not normal.

"There have always been records of birds with long beaks, but what we see is a concentration of them, and that is troubling," Anderson said.

Some oversized beaks Anderson has found are just a few centimeters too long. Others are too long by a matter of inches.

In some cases, birds have been able to adjust to the deformations and continue to hunt. Others are hopelessly starving to death.

As new instances of the disorder are reported to Anderson, he said he worries the disorder may be far more widespread and far more serious than he yet realizes.

"The wildlife population is a finely balanced unit," he said. "Add something there to tip the balance and it creates problems."

A disorder among hawks could have ramifications throughout their ecosystem.

Hawks are the primary predators of many ground rodents — mice, voles and gophers — as well as smaller birds. If the hawks cannot hunt these animals, their population could grow unchecked and have a serious impact on farmland.

The red-tailed hawk is found across the country. Researchers fear that, if the cause of the long beaks is something like a virus or a bacteria, it could affect hawks nationwide.

Biologists do not know exactly how a bird’s body controls a growing beak or what seems to be interfering. Possibilities include environmental pollution, a virus, bacteria, fungus, or a vitamin or mineral deficiency in the bird’s diet.

Anderson first saw a red-tailed hawk with the deformity in 1997. He has only been seriously looking for the disorder in hawks for the last two years.

As far as he knows, he is the only raptor researcher trying to document cases of the disorder, which may explain why there seems to be a concentration of birds with it in western Washington, he said.

"The question that keeps me awake at night is, what if the cluster in western Washington is happening all the way down through California," he said.

"If we have this kind of density all the way down (the Pacific Coast), you can see why I’m concerned," Anderson said. "Our most pressing need is to determine how widespread it is."

To help solve the mystery, Anderson is recruiting bird-watchers to pay closer attention to red-tailed hawks and falcons.

Experienced bird-watchers — the ones with powerful spotting scopes — tend to ignore the common red-tailed hawk, Anderson said.

To add a report of a deformed hawk to his current catalog, Anderson said he needs some kind of photographic proof.

Details such as the condition of the bird and its behavior, along with where and when it was spotted, is valuable data that could yield clues and help lead researchers to discover the cause of the deformity.

The deformed beaks make it harder, if not impossible for the hawks to tear apart the tough skin of their prey.

The top portion of the beak — the maxilla — can become unwieldy or dull. The lower half — the mandible — can curve downward or be pushed to the side, which makes it harder for the bird to grip the flesh of its prey.

Normally, a bird keeps its beak sharp and the right length by rubbing away the keratin as it grows.

Keratin is the same material that makes up a bird’s feathers and its talons. It is the same material that human fingernails are made of. Where humans cut their fingernails, birds wear down their beaks through their normal day-to-day routine.

The long bills seem to stress the birds and they are more skittish. The affected birds have been reported looking for food in places like drainage ditches or eating road kill rather than trying to hunt.

At the Owl Rehabilitation Center in Richmond, British Columbia, the staff has seen long-billed hawks under incredible stress.

"A couple we’ve had in have resorted to eating slugs," said Bev Day, the center’s director. "They come in with the slug slime on their beaks."

As Anderson started dedicating more time to finding and documenting the long-billed hawks, he began sharing his findings with Colleen Handel, a researcher with the Anchorage-based Alaska Science Center, a branch of the U.S. Geological Survey.

Handel first saw deformed beaks in black-capped chickadees, small birds that use their beaks to dig insects out of tree bark. Chickadees are common in residential areas.

"It is heart-wrenching," Handel said. "Once their bill gets grossly deformed, they can only survive because people put food out. They can’t peck. They rely on peanut butter and soft foods by the end of February or March, if they survived that long, they look really dirty and ratty."

Handel started a database of deformed birds in 2000. It is the first official form of record-keeping and could help Handel spot a pattern in the deformities.

To date, she has received about 200 reports of the long-billed phenomenon in 27 other species, including the bald eagle. She has seen the disorder in about 1,200 chickadees, about 10 percent of the population, "a pretty alarming percentage," Handel said. A natural rate of occurrence in the wild should be about half a percent, she said.

She has limited her research to birds in Alaska because she said she fears being overwhelmed with reports from Canada and the continental United States.

After five years of research, she still has more questions than answers.

The chickadees were tested for a number of fairly obvious causes but nothing was found. The disorder does not seem to be transferred from parent to chick, lowering the likelihood that the long bills are a genetic disorder. To Handel, the lack of genetic cause makes it more likely that the source of the disorder comes from some type of pollutant or illness.

At this point, Anderson is more hesitant to point to pollution.

"To imply that would be to mislead the research, to mislead the public and to mislead science at this time," Anderson said. "You’ve got to have the data to prove that."

Handel lists environmental pollutants along with any number of other possible causes. She said pollution from Asia is carried in the atmosphere over Alaska.

Anderson has sent four frozen red-tailed hawks with the beak disorder to the U.S. Geological Survey in Madison, Wis. Rex Sohn, a disease specialist at the lab, said the frozen samples did not yield any answers.

Sohn will continue to test birds Anderson sends him, but said he and Anderson need more data about the deformed birds before a scientist could convince a group to provide serious research money.

Handel said she has been able to build her database and conduct her research in Alaska with help from people keeping an eye on their bird feeders. They take pictures and send them to Handel.

"Most of the people that call me up with reports of birds that come to their feeder have named them," Handel said. "Their name is either because of the behavior of the bird, or the nature of their beak. One called a bird Cyrano."