A different form of biological control ...
http://www.latimes.com/news/science/la-me-falcons13nov13,0,7433223.story?coll=la%2Dnews%2Dscience
Falcons' Talon Show Scatters Gulls
Four of the predators are loosed upon a large and polluting shorebird
population at a San Juan Capistrano landfill.
By Stanley Allison
Times Staff Writer
November 13 2002
Well, there goes the neighborhood.
Four falcons -- put on the county payroll as part of a five-month experiment to
rid a San Juan Capistrano landfill of thousands of gulls -- moved in Tuesday and
quickly showed who's boss, harassing and bullying the longtime residents.
As soon as one of the trained falcons was released, the California gulls,
considered a menace by employees and a potential source of bacterial pollution
by county officials, took to the air.
"While he's in the air, the gulls don't feel comfortable on the ground," said
David Knudson, owner of KlearView Resources, the Spokane, Wash., company that
supplies the falcons.
The lanner and saker falcons, Knudson said, should quickly establish aerial
domination, and the gulls will just as quickly develop a healthy fear of the
county dump.
Using falcons to scare off lesser birds is not new. Knudson's falcons have been
employed at landfills and military bases throughout the West.
And the mission is always the same: clear the airspace.
"They'll have to go back to what they naturally do for food, which is not eat at
a dump," said Knudson of his target. "They now have to learn to live and forage
someplace else."
Which is just what the county's Integrated Waste Management Department, which
operates the landfill, wants.
The gulls, along with a sprinkling of crows, pigeons, starlings and other
scavengers, have dined at the landfill since it opened in 1976. Feasting on the
2,300 or so tons of municipal waste dumped there daily, the gulls wreak havoc on
vehicles and employees, making things, well, messy.
The landfill is three miles from the sea and near the ocean-bound San Juan
Creek. The thousands of gulls and other birds that leave their droppings
throughout the 1,530-acre landfill create potential health, safety and
water-quality hazards.
Over the years, the county has tried many scare tactics to chase away the
gulls, including:
* A zone gun, which resembles a small cannon that creates a noise at preset
intervals. The birds got used to it and ignored it.
* Bird wire, strung above the working area on poles in a crisscross fashion. The
birds figured out that they could walk under it.
* Flash tape, a reflective material that hangs from the wire to scare them.
Again, they ignored it and walked under it to get to the garbage.
* Bird distress calls, broadcast from an earthmover equipped with a loudspeaker.
The birds adapted and ignored it.
* Kaleidoscope lights, like at a disco. That lasted about half a day before it
became clear they wouldn't do the trick.
* Inflatable owls placed around the site. The birds got used to them.
* Whistles and noisemakers. They got used to them.
* Cracker shells, very loud explosions from a shotgun. Neighbors complained
about the noise, and the department discontinued their use.
With few options left, county officials turned to Knudson, who has rid other
West Coast landfills of problem birds.
The falconer, who has 18 birds, has contracts with about six landfills and
military bases in the West.
The falcons do not necessarily harm the gulls, unless the birds unwisely choose
to ignore the raptors.
"We're talking about scaring birds as opposed to killing them," Knudson said.
His falcons -- Ahmed, the Prince, Wanda and Faith -- will be at the landfill
five or six days a week, flying in 20-minute shifts.
The falcons are territorial and aggressive, handy traits in the gull operation.
Put up against gulls and other lesser birds, the falcons -- which Knudson said
have been clocked at 227 mph in a full dive -- will take control of the area
almost immediately.
"They're all about force," he said.
The gulls and other scavenger birds will look elsewhere for their food.
"I don't know where," Knudson said. "They'll probably go back to the ocean where
they belong. We've created an unnatural food source and an unnatural population
of gulls."
As they are forced to abandon the dump as a food supply, the population will
eventually thin to natural levels, he said.
At the end of the five-month, $40,000 experiment, Knudson and county officials
will assess its effectiveness. If the falcons have worked, the falconer will
return periodically to maintain the friendly skies.
Supervisor Tom Wilson, who observed the falcons' inaugural flights, was
impressed. "We can demonstrate that we're being proactive rather than reactive,"
he said. "This looks like an effective way of improving this space."
Birding-Aus is on the Web at
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