Pilots should take heed of wildlife patterns | Photo gallery
The collision with a flock of geese that forced down the Airbus 320 on the Hudson River didn't surprise Mike Begier.
The head of the U.S. Dept. of Agriculture Wildlife Services program that works to alleviate wildlife hazards said the flight path leaving New York's La Guardia Airport also is used by migratory waterfowl. An avian-aviation encounter was imminent.
"This was an accident that was waiting to happen," said Begier, national coordinator of the Airport Wildlife Hazards Program. "We have an expanding population of large birds in North America, and they're using air space around airports.
"On average, there are 25 bird strikes a day that occur across the country. The overwhelming majority of those strikes are non-damaging, and pilots, passengers and airport officials never even realize they occur."
About 14 percent of strikes are damaging, Begier said, "where there is some sort of negative effect on flight or damage that is noticed."
Since 1990, wildlife strikes cost U.S. civil and military aviation more than $500 million annually and have killed at least 156 people and destroyed more than 120 aircraft, Begier wrote in a report.
Since the late 1980s, the airport hazards program has worked with more than 700 airports and airbases throughout the country to lessen the potential for wildlife strikes to aircraft, said Carol Bannerman, USDA Public Affairs Specialist. The USDA conducts wildlife hazard assessments at airports, develops mitigation plans and carries out the recommended program or trains airport staff to do so.
"An airport's ecological and geographic situation influences the types of wildlife presenting concerns as well as how to reduce hazards," Bannerman said. "Every airport has its own set of problems with its own ecology and species."
Bannerman said issues range from deer at heavily wooded West Virginia airports to Arizona airports overrun with prairie dogs. Airports along flyways for migratory waterfowl are of great concern as well.
Other considerations are large water birds like herons foraging in drainage areas, small flocking birds like starlings, and she said there is also an increase in collisions with raptors. The program develops remedies for each set of circumstances.
"General aviation airports, they actually face a greater degree of hazards in some respects, because a lot of them are located in rural areas," Begier said, "and there's not a lot of funding to address wildlife protection."
Wildlife Services personnel have written numerous publications on management techniques based on their scientific research, and the internationally recognized findings are used by airport managers to justify and defend wildlife hazard management programs.
"A lot of people refer to (strikes) as an act of God," Begier said. "We have a lot of knowledge, and we are working on awareness. There is still a lot we need to do to inform the public, or inform the pilot."
Taking off
The program began in the late 1980s as increasing air traffic coincided with an increase in wildlife and bird-plane strikes. The Federal Aviation Administration, which had recorded strikes since 1965 but hadn't entered them into a database, and the Department of Defense asked Wildlife Services to reduce wildlife hazards to aviation.
"We're the federal entity that deals with wildlife damage management and conflicts of wildlife and people," he said. "Airport wildlife hazard falls under human health and safety."
The WS program started training personnel, conducting research and applying techniques at airports. Its mission is to determine which species are causing problems and offer remedies to eliminate those risks.
Begier's report from 2004 to mark the 15th year of the program noted that non-migrating Canada goose populations in North American increased 9 percent each year from 1970-2002 to more than 3.5 million. And most of the 36 North American bird species larger than 4 pounds also increased in numbers, and most of those are flocking birds, increasing the probability of multiple strikes.
The increase in white-tailed deer in the U.S. and favorable habitat surrounding airports was also cited in the report. USDA data show 600 deer-aircraft collisions in the U.S. from 1990-2003. Coyote and other mammals were also mentioned as hazards.
The majority of airports are in flat or low-lying areas with green spaces and water nearby – areas that hold wildlife.
"That's exactly the issue," Begier said. "Since we've been keeping this database for the FAA over the last 18 years, we have 82,000 records that detail these strikes and 98 percent involve birds. Two percent involve other mammals, coyote and deer predominately."
The database relies on strike reports from pilots, airport personnel, air traffic control towers, airport operations personnel and carcasses found within 200 feet of a runway centerline unless another reason for the animal's death is identified, but Begier said many incidents go unnoticed or unreported.
"It's very hard to quantify that. The system of reporting to the wildlife strike database is a voluntary basis, not mandatory," he said. "We really encourage people to report. We can fix problems, but we can't if we don't know.
"We have 82,000 records. We've done some scientific studies and we estimate that's only 20 percent of the reports. Eighty percent are not reported."
Flight plans
The hazards program has three cornerstones to mitigate problems: habitat management, frightening off or relocating wildlife, and as a last resort, depredation.
Begier said habitat management is used first and foremost. Airports simply create less hospitable conditions for wildlife from getting there or wanting to be there.
"Putting up an appropriate fence to keep deer out, you're changing the habit," Begier said. "There may be something in particular the wildlife are using as a food source, so removing something in the grass that attracts wildlife. A trained biologist would go and recommend eliminating this grass or shrub."
One success story occurred at an air force base that was having issues with ground-nesting meadowlarks. A biologist determined that the birds desired a certain height of grass, and the recommendation was to simply keep the grass cut shorter. That reduced strikes there 75 percent, Begier said.
"It can be as simple as eliminating worms coming out on runways for gulls, grasshoppers that would draw birds, woodchucks in the ground to bring more predator birds," he said. "Runways often have to have drainage ditches, and they often have great blue heron in the drainage ditch. It needs to be cleaned out properly."
Frightening away wildlife like waterfowl and other flocks of birds can be done with propane canons, pyrotechnics or other loud noisemakers. One airport discourages waterfowl by placing black floating balls in waterways.
"We are basically trying to scare the bird away from the airport," Begier said.
With eagles, kestrels, osprey and other raptors, relocation is considered. Bannerman said an immature bald eagle was recently moved from Minneapolis/St. Paul to northern Minnesota.
"He was actually fairly close to the airport," she said. "He has a tracking mechanism on him. It will be interesting to see what he does on his way back to the woods."
Begier said osprey chicks were taken off Langley Air Force Base and sent to help reestablish the population in Ohio. "That was a good collaboration."
The tactic of last resort is depredation, or killing the species.
"There are allowances in the Department of Interior in the federal code that if an airport needs a depredation permit, we can do that," said Begier, noting an exception to threatened or endangered species. "All airports can acquire these permits and do this work on their own."
The WS has recommended airports adopt zero tolerance for deer, and that deer removal should be done by professional shooters. They call for 3-meter high fencing and cattle guards at gates that might allow deer to enter airport operations areas.
"This is an interesting statistic," Begier said. "Ninety percent of the time when deer and aircraft meet on a runway, there's significant damage to the aircraft."
One small bird of major concern is the European starling, referred to as "feathered bullets." The deadliest U.S. bird-plane disaster occurred in 1960 when a passenger plane taking off from Boston hit a flock of European starlings and crashed, killing all 62 people aboard.
"They can be very, very hazardous at airports because they fly in big flocks and have a very high density that's particular to them," Begier said. "In the industry, they are referred to as feathered bullets. People in the engine manufacturing industry coined that term. When they get into engines, they can cause a tremendous amount of damage. Lethal removal could be starlings."
The FAA requires airports that experience an incident to have a hazard assessment, which Begier said can take a year to study wildlife through the seasons, but a remedy could be instituted immediately upon identifying the problem.
"The bottom-line message with a lot of this work," Begier said, "is we are stewards of wildlife and we're not doing them any favors by allowing them to live at the airport. We have to learn how to coexist."