The young peregrines then begin to capture birds and large insects on their own. On average, two eyases successfully fledge per nest. Infertile eggs and natural losses of eyases account for this success rate. If the birds survive their first year, their chances for survival are good. Peregrine falcons are distributed worldwide, occurring on every continent except Antarctica.
Some northern populations migrate long distances.
There are three subspecies of peregrines in North America. They differ slightly in appearance, breed in distinct regions and migrate different distances. This subspecies no longer exists east of the Mississippi. Historically, peregrines nested in Wisconsin on cliffs along the Wisconsin and upper Mississippi rivers and in Door County. Between 1965 and 1985, however, no peregrines nested in the state.