From the Columbus Dispatch in the USA:
Project brings back grassy fields — and raptors that hunt them
Sunday, February 04, 2007
When I began bird-watching during the 1960s, friends told me about or took me to prime locations.
One of the first places was the fields along Ross-Pickaway County Line Road, from Kingston east to Adelphi, southeast of Circleville.
The first short-eared owl I ever saw was there on March 25, 1962, on a field trip led by the late Irving Kassoy of Columbus.
I saw a rough-legged hawk for the first time during another trip there.
All three species fed on small rodents that lived in the grasslands of those fields.
As farming practices changed through the years, more fields were bare. As the small rodents’ habitat dwindled, so did their numbers.
With that food source mostly gone, the Northern harriers, roughlegged hawks and short-eared owls went elsewhere. During a Jan. 11 trip to the area, I saw none of the three species.
But just 10 miles to the northwest, in Pickaway County, there are grass-covered fields now, and raptors have found them.
A hunter’s gaze betrays its strategy. And looking at what an animal looks at when it’s hunting for prey has revealed foraging patterns in humans, other primates — and now, birds. Suzanne Amador Kane of Haverford College in Pennsylvania and her colleagues watched archival footage of three raptor species hunting: northern goshawks (Accipiter gentilis), Cooper’s hawks (A. cooperii) and red-tailed hawks (Buteo jamaicensis). They also mounted a video camera to the head of a goshawk to record the bird’s perspective (a technique that’s proved useful in previous studies of attack behavior). The team noted how long birds spent fixating on specific points before giving up, moving their head and, thus, shifting their gaze: here.