The bald eagle population has rebounded in recent years. Unfortunately, eagle-aircraft collisions are also on the rise, increasing 2,200 percent since 1990.
A better understanding of bald eagle behavior could help airfield managers develop countermeasures. To that end, a team of researchers used GPS telemetry units to track the flight paths of 32 young eagles in the Chesapeake Bay area.
Bald eagles tend to congregate near airports because “they like to loaf around,” says Tricia Miller at West Virginia University, one of the study’s authors. Surrounded by tall wetland plants, forests, and housing developments, Miller says the birds prefer airfields, “which are open, park-like landscapes that give them a nice grassy place to sit and in some cases view the water.”
And, water, it turns out, is a key factor in predicting eagle flight paths. Young bald eagles, who are less experienced in avoiding aircraft, tend to not venture far from nesting areas—except to search for fresh water. The study warns that eagles who nest in a lower quality habitat with lots of saltwater may pose a greater risk to aircraft than those nesting in a higher quality habitat because they fly further in search of water. With knowledge of where airports are located relative to nests and fresh water sources, airfield managers might be able to better anticipate the flight paths of bald eagles and determine which airfields are most at risk.