Birdcasting

Swainson’s Hawk

When birds share airspace on airplanes, collisions are imminent. Meteorologist George Young created a bird forecasting model to help pilots plan routes around birds like this Swainson's Hawk. The hawk wears a transmitter on its back that monitors how high it flies.

George Young tracks birds. He begins with satellite data: maps of yellow, green, and red blobs indicating the heat that radiates from grassy fields, patches of shrubbery, and parking lots. From experience, Young knows which birds live in those habitats. "In grassy areas you might see a short-eared owl or a horned lark," he says.

"You look at the land use on the satellite map, then the terrain on a topographic map," explains Young. "From there you figure out which plant species will be in that area. Rhododendron, for example, will grow on the north-facing slope of a mountain. And from the plants, you can figure out the bird species." Young can drive to the area he has pinpointed and be almost dead sure that he will find the right birds, the birds he predicted, within walking distance of his car.

As a meteorologist, Young tracks the air as well: warm currents rising like balloons, cool air sinking to the ground. He used to forecast air patterns for glider competitions. Young calls this kind of forecasting "the little game I play with air." Part of the game involves knowing when to use wind over the mountain ridges to send the glider—with its engineless fiberglass body and 50- to 75-foot wingspan—screaming into the next state. The trick to a successful glider flight is to soar as high as possible in one updraft so that you can glide far enough to catch the next updraft.

Lately Young, an associate professor of meteorology and geoenvironmental engineering at Penn State, has been birdcasting—forecasting patterns of bird flight using meteorological and biological data. "In the military, there's been this ongoing concern about birds big enough to wreck engines. There are an awful lot of pelicans in Nevada where the Navy's 'Top Gun' school is now based." When birds—alone or in flocks—share airspace with planes, collisions are imminent. Birds bust nose-cones, smash windshields, and jam engines, rendering planes inoperative. "Get a pelican down the engine of a B2 and you've bought yourself another $500-million plane," Young says. Most airplane engines and windshields are only built to withstand the force of a two-pound bird, not a 20-pound pelican. (The Federal Aviation Administration tests this two-pound standard by using a cannon to hurl chicken carcasses at the engines.)

"Visions of bombers flying through flocks of pelicans," Young adds, prompted the Department of Defense to enlist the help of the Center for Conservation Research and Technology (CCRT), a wildlife research organization based at the University of Maryland, Baltimore County. The CCRT called Young.

"We needed someone with knowledge of birds, soaring models, and boundary layer meteorology," says William Seegar, founding director of the CCRT. "That person was George Young." Young and a group from the CCRT designed a bird forecasting model that will help prevent bird-plane collisions in the air.

"There's not much difference forecasting for gliders and forecasting for birds," says Young. "It's just a difference in scale."

The bird model that Young and graduate student Harlan Shannon created is like the meteorological models that forecast weather. "It predicts how high above the earth's surface the thermals will be, and how high within those thermals a bird will soar," Young explains. The depth of the thermals—columns of rising warm air above the earth's surface—depends on high and low temperatures. "So high and low temperatures dictate how high the birds will soar," says Young.

"The influence of the weather on different bird species varies," says"For example, some soaring birds fly high when the thermal layer that supports their flight is deep and strong. Other soaring birds will fly low, regardless of the depth and intensity of this thermal layer." Young adds: "Some birds like to stay within sight of mice, so they won't go above 500 feet. Others will go much higher, but not above 14,000 feet, because it's too cold."

Seegar, at the CCRT, developed a 20-gram transmitter terminal that is light enough for birds to carry as a backpack. The transmitter locates the bird (with an accuracy of 150 meters) via the ARGOS satellite system. "The math for the bird forecasting model has been around for years," says Seegar, "biologists just haven't been able to match bird flight data to the meteorological models. But now that we're able to track bird flight using small transmitters that the birds can wear, we can take the old math and create new models."

So far the researchers have created modeling systems for three soaring birds: American White Pelicans, Turkey Vultures, and Swainson's Hawks. Young envisions a bird forecast being presented to pilots in much the same way that weather data now is. "The bird model will tell pilots a day in advance how high the birds are likely to soar based on weather conditions," says Young. "Pilots can then plan flight routes to avoid collisions."

George Young, Ph.D., is associate professor of meteorology and geoenvironmental engineering in the College of Earth and Mineral Sciences, 621 Walker Bldg., University Park, PA 16802; 814-863-4228; young@ems.psu.edu. William Seegar, Ph.D., is director of the Center for Conservation Research and Technology at the University of Maryland, Baltimore County; www.ccrt.org. The Department of Defense Legacy Resource Management Program funds the project.

Last Updated May 01, 2000