Lasers Being Deployed in Campaign Against Bird Strikes

'Avian dissuaders' can help but are not a cure-all against birds flocking at airports

Lasers are being employed to frighten birds away from airports, marking the deployment of yet another means of combating the threat posed by birds colliding with airplanes.

A robot controlled green laser has been deployed at France's Montpellier airport, in a test program to assay its effectiveness. The airport is located near marshes, a prime bird habitat, and the airport in the south of France accounts for fully a tenth of the country's bird impacts on airplanes.

The laser beam sweeps the runway to keep the birds from landing, according to an account of the Montpellier laser in the French press. Jean-Luc Briot, the French official behind the laser trial, likened it to "a painless stick which chases the birds away without disturbing the pilots."

When a low-power laser was used to disperse a huge flock of Canada geese at Pennsylvania's Lake Galena, the story in the Philadelphia Inquirer declared, "The laser beam shaved geese off the lake like a razor on black stubble."

The scientists and wildlife biologists dealing with the problem describe the birds' reaction to the approaching laser beam as a "neophobic avoidance response." The geese were responding to an unnatural new "threat."

If the laser causes the birds to fly away,it does not mean they'll stay away. In one test of lasers against crows roosting at night in urban in treetops, the crows returned to their perches after about 15 minutes. According to the 2002 report of this experiment, "The laser beam produced a startle reaction comparable to that produced by a sudden, loud noise, but imparted no threat sufficient to cause desertion of a roost."

The effectiveness of the laser, wildlife scientists have found, is species-specific and context-specific.

Nonetheless, low power lasers are seen as a potential weapon in the continuing campaign to minimize the risk of bird strikes. According to Richard Dolbeer, national coordinator for airport safety at the National Wildlife Research Center in Sandusky, Ohio, more than 50,000 bird strikes on aircraft have been recorded in the United States since 1990. That total figure suggests an average rate of about nine bird-airplane collisions per day. Significant damage to engines and structure can result, as noted recently in this publication (see ASW, March 15, "flocking suicide" at Sacramento, Calif., and ASW, March 29, event at Cleveland, Ohio).

"There is a lot of product promotion" about lasers, when more research is needed, said Bradley Blackwell, a wildlife biologist at the National Wildlife Research Center. Much of the research into airport wildlife control (birds, deer, etc.) is conducted at this facility.

Blackwell told ASW of the French trial, "I am pleased to see Dr. Briot's work is now operational at an airport. Unless the energy level is substantial - and I doubt this because of safety concerns - this green laser is likely only effective during periods of high contrast, that is, dark, or with fog or other particulate matter in the air."

"Still, if the timing of the beam sweep is depended on a motion sensor or is variable, a laser sweeping across the runway at night probably will reduce the presence of loafing gulls," Blackwell added. Unless integrated with other measures, such as habitat and population control (mowing of grass, destroying eggs), Blackwell said, "habituation to the beam remains a concern."

No one method works. In military terms, bird control is like a combined arms operation, involving the integration of numerous complementary measures. "The big take-home message is that the moderate power lasers (5-500mW), like the Avian Dissuader, represent one tool in the biologist's box," Blackwell said.

Light has long been considered a tool for bird control. More than 30 years ago, it was suggested that runway lights exclude wavelengths less than 500 nanometers to reduce the attractions of insects and, subsequently, their avian predators.

Low-power lasers developed more recently offer a number of characteristics useful in bird control: light weight, portability, silent operation, long range (hundreds of feet), no fire hazard (up to Class IIIB lasers), and no reported injury to birds. However, birds of different species react differently to lasers.

"The bird has to see it, and the bird has to perceive it as dangerous," Blackwell said.

The laser concept came out of the problem of seagulls perched on the helipads of offshore oil and gas rigs in the Gulf of Mexico, Blackwell explained.

"So we got to thinking about how to remotely protect these landing spaces, and we thought of lasers," Blackwell said.

In low ambient light, the bright laser beam causes the birds to move away from it. However, best results have been obtained in low-light conditions (sunset through dawn), and bird reactions vary by species, as evidenced by the discouraging results with crows. However, Blackwell said, "Canada geese respond beautifully. They panic. Some run. Some take flight." This is the "neophobic avoidance response" alluded to above.

One of the concerns is the potential damage to birds' eyes. In tests conducted through the National Wildlife Research Center's Mississippi Field Station, double-crested cormorants were exposed to a moderate-power red laser at a distance as short as three feet. No eye damage was observed.

However, lasers used for bird control could potentially flash-blind a pilot momentarily. For this reason, airport managers must seek special permission from the Federal Aviation Administration for trial use of lasers at their facilities.

At many airports, deer pose a major hazard. Studies have shown that deer exposed to lasers do not exhibit the avoidance behavior of birds. Photos in a 2003 research paper show the deer placidly munching away with laser beams illuminating their bodies.

As far as mounting lasers on aircraft, "that won't happen," Blackwell asserted. "The safety issue is huge," he said.

"Any type of laser directed from an aircraft has the potential to impair the visibility of other pilots, not to mention ground-based traffic and personnel - be it aircraft on the taxiway, tower personnel, or the guy driving down the highway next to the airport. These beams travel some distance before the light is dispersed," Blackwell explained.

"What we hope to accomplish with aircraft mounted systems does not involve lasers. Instead, we hope to use the existing lighting systems via wavelength-specific light and varying pulse frequencies to, in effect, increase the visibility of the aircraft to birds," he said. The research is in its infancy, but Blackwell said he is encouraged by the preliminary results. >> Dolbeer, e-mail richard.a.dolbeer@aphis.usda.gov; Blackwell, e-mail bradley.f.blackwell@aphis.usda.gov<<

Eyeballs Compared - Birds & Humans

• Birds have proportionately larger eyes than humans, and the importance of vision to birds is shown in the relative size of the eyes to the skull. Eyeballs make up about 1 percent of the mass of the human head. For birds, the starling in this case, the eyes constitute some 15 percent of the head mass. In some species the combined weight of the eyes exceeds that of the brain.
• While retinal photo sensors in humans are based on three color channels (blue/green/red), birds see in four primary colors: ultraviolet (UV), blue, green and red. The UV sensitivity is likely correlated with scanning for aerial predators and for ground foraging.
• Tiny oil droplets in the light sensitive cones enhance the bird eye's sensitivity to hues.

Source: Understanding Avian Vision: The Key to Using Light in Bird Management, by Bradley Blackwell, Univ. of Calif., 2002

Airplanes Versus Avians

Bird strikes are an increasing problem for aviation:

• Populations are increasing of many bird species hazardous to aviation.
• Birds are adapting to urban settings.
• Air traffic is increasing.
• Jet aircraft are getting quieter.
• There is an increased liability issue associated with bird strikes.

Managing bird strikes in the airport environment creates unique challenges:

• Most strikes (90 percent) involve native bird species that are federally protected.
• The public is sensitive to the killing of birds.
• Birds are dynamic, often flying 25 miles or more daily between their nesting/roosting sites and feeding areas.
• Birds rapidly "habituate" to most non-lethal frightening devices and techniques.
• A third of bird strikes (34 percent) occur at night.

Laser applications at airports:

• Dispersal of birds from night roosts.
• Dispersal of birds from bodies of water.
• Dispersal of birds from on and inside structures.
• Easily integrated with other management methods.

Source: National Wildlife Research Center, Ohio Field Station