The next generation of wildlife biologists is using a tool to help manage waterfowl, and migratory birds in general. It's the same tool you might rely on hoping to see tomorrow's sky will be dark, blustery and gray. It's NEXRAD Doppler radar.
In the eddies of your mind, swirling there is a composite imagery.
It's always November. The sky is a variegated gray. Its five shades are amoving misty pale, smudged dark and sooty. The sun struggles to showitself on the horizon through the mass of clouds. In the crepuscular lightyou can see flecks, a mass of birds, moving over the treetops, levelalmost, going left to right over the marsh. Wings whistle. Headlong, theytake a look at the decoys. They drop air from their cupped wings, and theadrenalin stokes you.
It's a scene you hope plays out this coming waterfowl season, watchingbirds get up and get on you. How the birds behave is somewhat predictable.They get restless to break their fast, and get to the fields to feed.
When they move, and where they go, is becoming clearer to science. Thenext generation of wildlife biologists is using a tool to help managewaterfowl, and migratory birds in general. It's the same tool you mightrely on hoping to see tomorrow's sky will be dark, blustery and gray. It'sNEXRAD Doppler radar.
NEXRAD stands for "next generation radar," new and improved radar far morerefined and sensitive than the original radar put into common use going on60 years ago.
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Its sensitivity to skyward objects makes it useful to biologists and landmanagers. The same radar that produces imagery for your weather forecast,or helps direct jet airliner traffic, also picks up bird traffic. In fact,NEXRAD is so sensitive, if can even detect grains of pollen wafting in thewind.
Here's how it works. NEXRAD sends microwaves into the sky. The wavesstrike an object like rain drops, a plane, or duck. Most of the microwavesscatter, but some of the signal bounces back to the radar. It's done veryrapidly, about 1,300 microwave pulses per second. As objects in the skymove, the signal changes over time, shown as movement on a NEXRAD screen.The technology also illustrates by color, the density of a flock of birds(or moisture content in the air), and which way they are traveling, and howfast they fly.
It's a coarse tool for biologists. They can't yet tell what species thebirds are looking at NEXRAD imagery, but the sizes of birds do createdifferent signals. The speed, at which they fly, too, also creates adifferent signal. Biologists can follow the nocturnal migrations. At anytime of day, when birds are in the air at least, biologists can get aninstantaneous broad-scale look at what birds are doing.
It has proven to be beneficial in land management. NEXRAD imagery lets yousee the linkage of the lands that surround wildlife refuges. It letsbiologists see where waterfowl roost, and where they take flight to feed,and where they light. It's been extremely useful in that regard for landacquisition to conserve important habitat. San Bernard National WildlifeRefuge on the Texas coast used NEXRAD to locate an important tract ofbottomland hardwoods that 249 species of birds needed. They "fallout" ofthe sky and find respite in these Texas bottomland woods following agrueling 400-mile non-stop trek across the Gulf of Mexico. These birdsrefuel on the refuge, then fan out to the eastern two-thirds of the US andadd color and music to backyards, wetlands, and woodlots from Maine toMontana.
NEXRAD offers utility in conservation by identifying the corridor thatbirds migrate. That gives land managers a tool in finding good places tolocate communications towers and wind-powered generators.
This waterfowl season, as your experiences add to the imagery pooled inyour mind, know too, the birds are also probably creating radar imagery -and data that scientists can put to good use for conservation.
Springer works for the U.S. Fish & Wildlife Service. ContactThis email address is being protected from spambots. You need JavaScript enabled to view it.
PHOTO: NEXRAD picks up an evening flight of wintering waterfowl atLacassine National Wildlife Refuge, Louisiana. NOAA image.
Source: U.S. Fish & Wildlife Service
