(CNN) -- The problem of planes hitting birds comes down to a key fact: "We're competing for airspace," says Richard Dolbeer, a biologist who spent 20 years studying the problem at the U.S. Department of Agriculture
Populations of large birds have increased dramatically since the 1970s, when environmental regulations were instituted in the United States. Birds have become more accustomed to living in urban environments near airports and the number of airline flights has risen sharply, according to Dolbeer.
Dolbeer, who retired in September 2008 and is now a consultant on the issue, spoke with CNN hours after a US Airways plane crash-landed in the Hudson River in New York after an apparent bird strike. He retired as National Coordinator for the Airport Wildlife Hazards Program and was chairperson of Bird Strike Committee-USA from 1997-2008.
