Meteorologists once treated the signals from flying animals as a nuisance that complicated their measurements. But recent improvements in computing power and networking of radar stations have turned that nuisance signal into a valuable data source on animal ecology.See also: Mayflies seen on radar.
"One of the things that's most exciting to me is that we sometimes see an airmass that's moving, like a weather front, and insects actually get trapped up in that - you can see the insects pooling up along this air mass. If this happens to pass over the bat caves at sunset, the bats come out and distribute themselves right along that gust front and presumably gobble up those insects. Marine biologists probably think that kind of thing happens all the time in the ocean, but we've never been able to see that in the aerosphere."
21 February 2011
From the BBC: