With fury in its tiny dark eyes, the black-capped chickadee struggled to
escape research technician Lisa Pajot by pecking her fingers. But tips of the
bird's deformed beak had grown apart since its last monthly exam and it could
not pinch the skin.
Its feathers were dirty and a bit frayed too -- potentially fatal problems for a
wild bird.
"He can't preen properly and keep himself clean," Pajot said recently as she and
federal bird biologist Colleen Handel inspected the tiny songbird in a U.S.
Geological Survey lab off Tudor Road.
Captured 15 months ago in South Anchorage, with a bill three times longer than
normal, the adult male chickadee has become part of a scientific investigation
into a mysterious epidemic of beak deformities that surfaced in the 1990s and
continues. Through February, 1,211 individual chickadees and 195 birds of 27
other species have been found in Alaska with crossed, curled or malformed
mandibles. The reports stretch from Bristol Bay to Fairbanks, from Juneau to the
Matanuska and Susitna valleys. They include 42 northwestern crows in Southeast
as well as 37 black-billed magpies, 28 Steller's jays, 21 downy woodpeckers,
plus robins, ravens, nuthatches and others.
Such deformities are not unknown, but they appear to be rare anywhere else in
the country. Some migratory birds arrive in Alaska with straight beaks but have
young that develop the problem here.
For reasons unclear, most of the deformities appear in birds that forage and
nest in Anchorage, Mat-Su and Kenai Peninsula woods, with especially high
numbers on the Anchorage Hillside, Handel said.
"There could be something affecting a wide array of species, but we don't know
what that is or how it's operating," said Handel, lead land bird researcher with
the Geological Survey's Alaska Science Center in Anchorage.
"It's the lack of information that is most frightening. ... One of the hidden
questions is what might be happening to human beings."
"It's a great mystery, and I think it's got the attention of ornithologists and
other scientists around the country," added biologist Stan Senner, executive
director of Audubon Alaska. "People should be concerned because birds are the
proverbial canary in the coal mine."
One of the most common Alaska forest birds, black-capped chickadees flit in
small flocks through the trees in search of seeds or insects, recognizable by
their "chick-a-dee-dee-dee" call. They're little -- running 40 or 50 to the
pound -- but feisty and smart. They're so good at finding food and remembering
stashes that other birds will follow them, Handel said.
Reports of deformities peaked in 1999 and 2000 after extensive publicity in
local newspapers and on TV. Including birds seen more than once, Handel has
logged 1,689 chickadee reports between 1991 and 2004.
By contrast, she has uncovered 12 reports of deformed chickadees from Ontario
and the Lower 48 between 1987 and 2000.
"What drives me crazy is I try to think about all the possibilities, and I
always come back to: Why Alaska? What's so different up here that we're getting
this and no one else is?" Handel wondered.
With about $150,000 in federal funding, Handel began an investigation in 2000
with Pajot, Julie Stotts and John Terenzi at the science center, and Kim Trust
and Steve Matsuoka at the U.S. Fish and Wildlife Service. The team has looked
into genetics, nutrition, diseases, parasites and other potential causes but has
few answers yet.
Tests for organic contaminants and pesticides in 20 deformed birds should be
done this spring. Handel hopes the results will offer clues.
Using a network of 250 nest boxes and five winter capture sites, the research
team has found the problem in about 10 percent of chickadees captured four times
per year over the past four years. That rate is 20 times higher than expected
for a healthy wild population.
About the same rate was seen in April, Handel said. "Nothing is going away."
Bill deformities remain relatively rare in birds elsewhere in North America,
said Julie Craves, a researcher at the Rouge River Bird Observatory in Michigan.
She has written a scientific paper about the deformities in another species and
maintains a list of reports.
"The incidence in Alaska is surely very significant," she wrote in an e-mail.
"Chickadees are so common as feeder birds across the continent that if there
were a 10 percent rate anywhere else, it would almost certainly be reported. I
am both intrigued and concerned about the Alaska situation."
Some elements of this riddle are known. The deformity shows up in resident
Alaska birds in all seasons. It doesn't seem to be inherited from parents or
appear at birth. It has been seen in male and female chickadees 6 months to 2
years old and is not limited to birds that use winter feeders.
The scientists have not found diseases, parasites or changes to the bony
structure at the base of the beak. Migratory birds don't arrive in Alaska with
the problem, but they sometimes develop it after hatching and feeding during
summer.
Handel and Pajot used eight remote cameras to monitor chickadees as they raise
young in nest boxes. One male bird had such a deformed bill that it could not
feed the hatchlings. So the bird would pass off seeds and larva to the female to
give to the offspring, Handel said.
About 40 chickadees captured and found to be normal were later recaptured with
deformed bills, allowing scientists to pinpoint when it happened. One chickadee
seen with a deformed bill was captured later in good shape. Handel kept that
bird for observation.
By process of elimination, the clues might seem to point toward an external
cause, like exposure to contaminants. But she said they can't rule anything out.
"We're still testing for a multitude of causes," she said. "There's kind of a
million different combinations, and you have to take them one by one and test
them one at a time."
Beaks are made of a fingernaillike material that continually grows and wears
down as the birds forage and peck. In a healthy bird, the upper and lower
mandible should stay aligned and wear at the same rate. Chickadee bills average
about 7 to 8 millimeters long. Figuring out why these bills grow to 21
millimeters or longer has been difficult partly because biologists don't know
precisely how the process is supposed to work.
For instance, they have discovered a single mandible can grow at different rates
along its own length. How does that happen? Is that normal? Handel wants to
capture and monitor healthy birds to find out more.
In the meantime, the captive male chickadee with the overgrowing bill has
managed to stay fat and chipper on a diet of powder vitamins, peanuts and pine
nuts, sunflower seeds and meal worms. It shares its cage with another male bird
with a lesser deformity, and lives at Pajot's house.
Wild birds with deformed bills have trouble keeping clean and finding enough to
eat. At feeders, they peck around on the ground, where they're easy prey.
"Both of these birds would have died by now," Handel said.
During last week's exam, Pajot finished measuring the growth on the bird's
misshapen bill -- 2.5 millimeters in one month. Then she trimmed the excess,
temporarily giving the bird a normal fit.
The 11.3-gram bird -- fairly plump for a chickadee -- didn't appear grateful.
With its newly sharpened beak, it began hammering away at Pajot's fingers.
"He can pinch me now," she said as she put it in the cage.