Cooper's Hawk Nest at the Arboretum

The Cooper's Hawk (Accipiter cooperii) is a medium-sized hawk. Adults have a dark cap, blue-gray upperparts and white underparts with reddish bars. They have red eyes and yellow legs. These birds capture prey from cover or while flying quickly through dense vegetation, relying almost totally on surprise. Most prey are mid-sized birds and small mammals.

Their breeding habitat are forested areas. The breeding pair builds a stick nest in large trees. The incubation period ranges from 30 to 36 days. The hatchlings are completely covered in white down. They are brooded for about two weeks by the female, while her mate forages for food. The fledging stage is reached at 25 to 34 days of age, though the offspring will return to the nest to be fed for up to 4 more weeks.

- Bill Eley, Program Development Director

Nesting Time Line

3/22 – Nest discovered by Arboretum visitor.

3/26 – Birds seen defending nest from squirrel.

4/10 – Eggs laid. (date is approximate)

5/15 – Chicks hatch. (date is approximate)

(Click on thumbnail image below to view larger image in new window.)

5/21/08	6/4/08
Chicks are alert. Adult female spends most of her time in the nest. Note females orange eye.	Chicks spend most of their time standing on the edge of the nest. Adult not always present. Juvenal feathers present on the breast and back (note: the term “juvenal” refers to feathers on a “juvenile” bird).
6/9/08	6/9/08
Juvenal plumage well developed, but some downy patches still present on the legs and behind the eyes. For comparison, note the fully adult plumage of the female at the nest.
6/9/08	6/9/08
6/9/08	6/9/08
6/12/08	6/17/08
Juveniles have begun to venture out of the nest and perch on adjacent limbs.	Birds rarely return to nest (except to receive prey from the female), and spend most of their time exploring adjacent trees. Constant calling between the birds takes place. Note that the juvenal plumage is complete, and the eyes and legs are yellow.
6/17/08	6/17/08
6/17/08	6/17/08
7/10/08	7/10/08
7/10/08	7/10/08
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The Arboretum would like to sincerely thank the following photographers for allowing us to share their photos on this website: Photograph of 5/21/08 by David McDonald; Photograph of 6/12/08 by Kathy Adams Clark; Photos of 7/10/08 by Sat Kartar Khalsa. All other photographs by Nigel Curlet Photographers reserve all rights to photos.