Length: 14 - 19 in. (females larger)
Weight.: 265-560 g. (females up to 22% heavier in spring)
Generalized predator takes small mammals, birds, amphibians, insects, reptiles and even crabs and fish on the wintering grounds.
One clutch per season, usually 2-3 young per clutch; most incubation by female; incubation 28-31 days and young first leave nest about 5-6 weeks of age; young often stay on territory with siblings and adults up to two months after fledging.
Documented living for 14 years and 4 months
Problems on breeding grounds and wintering grounds include habitat alteration, fragmentation and elimination, pesticide use on wintering grounds a potential problem, shooting on wintering grounds still common, short timber rotations may not allow for enough large trees for nesting, forest patches needed for roosting along major migration flyways.