In the early days of World War II, British radar operators noticed mysterious, ethereal shadows drifting across their screens. Those apparitions, so wonderfully dubbed angels by pioneering radar technicians, heralded the beginnings of radar ornithology. Radar's first major contribution to ornithology took form in 1958 when Sidney Gauthreaux, then a high school student in New Orleans, postulated that if radar can see planes and weather, why not birds? Only a few years later, as a Louisiana State graduate student, he found his proof. His radar images definitively proved the existence of massive trans-Gulf migrations. Prior to these observations, there was a continuing belief that the majority of migrants held to a more land-bound, clockwise pattern; arriving in North America via Mexico.

Through the 60's, 70's, and 80's, however, radar's promise failed to evolve fully. There were a few notable discoveries, such as in 1989 when Gauthreaux, working from archival images, awakened the ornithological world to the precipitous decline in migrating flocks -- down by nearly half when compared to the 1960's. The existing radar of the day, however, was proving largely inadequate. It lacked not only the necessary resolution, but it also failed to provide a three dimensional view.

The early 1990's saw dramatic progress. The new, highly efficient NEXRAD Doppler radar (Next Generation Radar) began to be placed into service. The Air Force started investigating NEXRAD's utility in their Bird Aircraft Strike Hazard Program (BASH). During this period, portable NEXRAD units were teamed with vertically mounted thermal imaging units so that the images captured by the radar could be visually verified. Elsewhere, graduate students studying under Dr. Gauthreaux were making their own exciting discoveries. Their breath-taking images of giant expanding aerial doughnuts were found to be thousands of Purple Martin radiating from critical roosting sites each morning.

Today NEXRAD's capabilities are being used in concert with other evolving technologies including the remote sensing of birds using radio and satellite telemetry, thermal imagery, bioacoustic monitoring, and the manipulation of the radar images to remove all weather. The conservation, health and safety, economic, and recreational potential of these complementary technologies is huge. From a better understanding of the migratory routes to safer air space to aid in planning the careful use of pesticides, the applications of these discoveries will surely touch us all as they make life easier for the birds.

To learn more about NEXRAD, read:
An Introduction to Radar Ornithology