Identification

Perching: Much larger than other accipiters. Adults have dark crowns, white "eyebrow" behind red eye, blue-gray backs, and white underparts with dense gray barring.

Flying: Wings are proportionately longer and tail proportionally shorter than Cooper's and sharp- shinned. But goshawks do show densely barred breast and long, banded tail typical of accipiters.

Nesting Habitat

Open conifer stands with large trees (often old-growth ponderosa pine), dense stands of spruce or fir, or mature aspen stands, usually between 2000 and 3200 m. No one is sure what constitutes optimal goshawk nesting habitat. In the Boulder Mountain Park they nest in 80-foot high ponderosa pines in remote north-facing canyons. In Rocky Mountain National Park pairs often nest in aspen groves near meadows. Adults are vocal and sometimes aggressive around the nest.

Nesting Dates

Courtship: April to May

Incubation: early May to mid-July

Dependent nestlings: early June to early August

Incubation of 2-5 eggs requires around 30-35 days, and young fledge 35-42 days after hatching.

Statewide Distribution and Population

They nest throughout the mountains and western plateaus, with highest nesting densities apparently occurring in the north-central mountains. They may be threatened in some areas by forest fragmentation, as they seem more sensitive than other accipiters to human disturbance.

Federal and State Status

Colorado State Wildlife Action Plan Tier 2 species; U.S. Forest Service and Colorado Natural Heritage Program species of concern.

Search and Nest Monitoring Protocol

Drive a set route beginning in mid-May, stopping every 500 m to look and listen for 10 minutes. After locating a territory, search suitable trees for nests. Visit nest sites every 2-3 weeks, observing for no more than 20 minutes at a time from a distance of at least 800 m.

Recommended Nest Buffer Area

No human encroachment within 800 m of active nests whenever possible.

References

Bent, A. C. 1937. Life histories of North American birds of prey, part 1. U.S. National Museum Bulletin 167, Washington, D.C.

Braun, C. E. et al. 1996. Northern Goshawk and forest management in the southwestern United States. Wildlife Society Technical Review 96-2.

Call, M. 1978. Nesting habitats and surveying techniques for common western raptors. U.S. Department of the Interior Technical Report 316.

Johnsgard, P. A. 1990. Hawks, eagles, and falcons of North America. Smithsonian Institution press, Washington, D.C.

Kingery, H. E., ed. 1998. Colorado breeding bird atlas. Colorado Bird Atlas Partnership, Denver.

Reynolds, R. T., and H. M. Wright. 1982. Nesting habitat preferences of accipiters in Oregon. Journal of Wildlife Management 46: 124-38.

Wickersham, L.E. 2016. The Second Colorado Breeding Bird Atlas. Colorado Bird Atlas Partnership, Denver.