By Denis Cuff
CONTRA COSTA TIMES
Posted on Mon, Jun. 20, 2005
|
| Brooks Island is home to nearly 800 pairs of Caspian Terns and hundreds of California and Western Gulls. (Gregory Urquiaga/Times) |
BROOKS ISLAND -
Fluffy, clumsy Caspian chicks huddled in nests
of open sand on a San Francisco Bay island where
danger perpetually lurks nearby.
A hungry
gull swooped into the colony, snatched a tern chick
and dumped it in the Bay.
The chick, too young to swim, floated face down before
the gulls ate it.
If the chick had lived a few more weeks, it might have
drowned from high tides washing over its nest.
Life begins with peril for the Caspian
terns on Brooks Island.
But the tall birds with the stout red beak and
mohawk-shaped black crown have flourished here, so
much so that the island near Richmond is a prime beachhead
in a federal plan to relocate a large batch of the
terns from Oregon's Columbia River, where they eat
endangered salmon.
In
a plan of unusual scope and distances, the federal
Fish and Wildlife Service proposes to break up and
disperse the world's largest Caspian tern colony from
a Columbia River island to seven places in California,
Oregon and Washington.
A sand spit on Brooks Island appears to be the best
of the relocation sites, which also include two shoreline
spots near Hayward and Fremont, scientists say.
No nets, traps or guards are involved in this relocation
of birds with wingspans that can exceed 4 feet.
Federal agencies plan to
lure the terns to new nesting areas by adding sand
and clearing weeds in isolated areas suitable for the
birds.
If necessary, managers will also
display decoys and blast recorded tern calls to entice
the birds.
Back
in Oregon, the federal wildlife manager plans to grow
tall plants to repel terns from a large expanse of
East Sand Island, a breeding ground for some 19,000
terns, or 70 percent of the West Coast population.
"I can't recall a
project that has relocated so many birds over these long distances," said
Nanette Seto, a Fish and Wildlife Service biologist based in Portland. "A
lot of people wonder whether it will work. We have
reason to think it will."
Spreading out the terns could help endangered salmon
runs, she said.
Terns could benefit, too, she said. Establishing multiple
colonies far apart would also give the West Coast tern
population more resiliency from disease or environmental
disasters, federal biologists said.
Environmentalists skeptical of the project question
whether terns significantly threaten endangered salmon.
They also say they worry the
project will fuel growing pressure on federal and state
agencies across the nation to relocate or even kill
birds that compete with endangered species damaged
by human activities like dams and development.
"They're moving
the terns because it's a politically expedient way to deal with the salmon
issue," said Alex Morgan, Seattle Audubon's conservation
director.
"We're not saying we will never support relocations," Morgan said, "but
we shouldn't make the Caspian tern the scapegoat
for problems that humans created."
Seattle Audubon was part of an environmental coalition
that sued the federal government after it began what
proved to be a successful relocation of the Columbia
River colony from one island near the coast to another
up river where salmon are less vulnerable.
In a 2002 lawsuit
settlement, the federal government pledged to develop
a salmon predation management plan and investigate
alternative nesting sites on the West Coast. That study
identified Brooks Island, an isolated East Bay Regional
Park District holding, as a prime spot.
Scientists are in their third year of a study
on the feasibility of luring more terns there.
To be sure, the terns
like the place.
The colony has grown from a single nesting pair in
1984 to more than 1,000 pairs last summer, scientists
report.
Brooks offers
the terns a rare, shrinking resource in the West: open
sand fairly well-protected from cats, coyotes and humans.
Caspian terns once thrived
in California's Central Valley wetlands, but habitat
destruction pushed them toward the coast.
"Brooks is a unique place," said Keith Larson, an
Oregon State University wildlife biologist who studies the terns on the island.
"There are not many habitats like this left."
On a misty June day,
Larson squeezed into a small bird blind on the island
to observe the birds and record their behaviors on
his hand-held computer.
The terns clustered
together in a tight pack of nests, holes scratched
out of the sand. The birds perpetually called, squawked
and pecked in the air to enforce their tiny family
territories of a few square feet.
"Peace is relative to the terns. They
are always on the edge of aggression," said Steve Bobzien, the East Bay Regional
Park District ecological services coordinator. "They
do what they need to do to be successful."
Caspian terns on Brooks Island have been observed flying
some 35 miles to Del Valle Reservoir in Livermore to
fish.
More often,
the terns plunge just below the Bay surface to snare
fish.
Larson said
his research suggests terns will not endanger fish
in San Francisco Bay, as some skeptics worry. The terns
feed primarily on the relatively common anchovy and
shiner perch.
The terns face their own problems on the Richmond island,
though.
Storms last winter washed away several feet of sand
spit shoreline, reducing nesting territory.
If the federal relocation plans
win approval this fall, environmental agencies would
haul in sand to rebuild the beach.
Crews also would remove island vegetation that the
terns avoid but gulls like for nests.
Wildlife officials also want to deal with
people, another threat. Officials are considering how
to improve warning signs to keep boaters away from
tern nests.
Larson said he has seen boaters
unknowingly cause chick deaths on Brooks by racing
inside the offshore "Keep
Out" buoys. This frightened off tern parents, allowing
gulls to steal the babies.
"The terns are very sensitive to disturbances," Larson
said.
Brooks Island, a one-time Indian settlement and later
a hunting club that counted Bing Crosby among its members,
has a long history of human use.
But the park district now limits visits to reserved
groups with their own boats. Live-in caretakers shoo
away unauthorized visitors.
Park
officials also close the breeding areas from April
through August, and they may expand that to year-round.
Park officials, however, are looking into the
possibility of developing an overnight camping area
for kayakers elsewhere on the island and an observation
deck for viewing the terns from a safe distance.
"We want to protect the Caspian terns," Bobzien said. "But
we also want the public to be able to appreciate
this natural resource."
© 2005 ContraCostaTimes.com and wire service sources. All Rights
Reserved.
http://www.contracostatimes.com