Cooper’s hawks build their nests in the crotch of a large tree, typically 25 to 50 feet above the ground, using sticks and lining the bowl with bark flakes. Nesting season runs from February through July across most of their range, with egg-laying peaking in April and chicks fledging by early July.
Background: A Forest Hawk That Adapted to Suburbs
The Cooper’s hawk (Accipiter cooperii) is a medium-sized accipiter found throughout North America, from southern Canada to Mexico. Historically a bird of mature deciduous and mixed forests, it has become a common breeder in suburban and urban areas over the past several decades. This adaptation is largely due to the abundance of prey—especially mourning doves, pigeons, and small songbirds—at backyard feeders, and the tall trees in residential neighborhoods that mimic its natural woodland habitat.
Named after naturalist William Cooper in 1828, this species is often confused with the slightly smaller sharp-shinned hawk. Cooper’s hawks are agile fliers, with short, rounded wings and a long, banded tail that helps them maneuver through dense vegetation while chasing prey.
Nest Site Selection and Construction
Cooper’s hawks are not particularly picky about tree species, but they show a strong preference for mature trees with a sturdy fork or horizontal branch that can support a bulky stick nest. Common choices include pines, oaks, maples, and beeches. In urban areas, they may nest in large shade trees in yards, parks, or along tree-lined streets.
The male typically selects the nest site and does most of the stick gathering, while the female arranges the material. The nest is a flat-topped platform of sticks, often 2 to 3 feet in diameter and 6 to 8 inches deep, lined with bark flakes, twigs, and sometimes green sprigs. Unlike some raptors, Cooper’s hawks do not add new material to the nest during the breeding season, but they may reuse and refurbish the same nest in successive years.
Egg Laying and Incubation
Clutch size ranges from 3 to 5 eggs, with 4 being most common. The eggs are pale blue-white, sometimes with faint brown blotches, and are laid at intervals of about two days. Incubation begins with the first or second egg, so hatching is asynchronous—chicks in the same nest can differ in size by several days.
The female does most of the incubating, while the male provides food. Incubation lasts about 34 to 36 days. During this period, the female rarely leaves the nest except for brief stretches to stretch or defecate. The male’s hunting success is critical, as the female depends on his deliveries.
Chick Rearing and Fledging
Hatchlings are covered in white down and are entirely dependent on the female for brooding and feeding. The male continues to bring prey, which the female tears into small pieces and feeds to the chicks. After about two weeks, the female also begins hunting, leaving the chicks alone for longer periods.
Young Cooper’s hawks leave the nest (fledge) at about 30 to 34 days old, but they remain near the nest and are fed by the parents for another 4 to 6 weeks. During this post-fledging period, the young practice perching and short flights, gradually developing the hunting skills they need to survive independently.
Common Nesting Problems and Misconceptions
One common misconception is that Cooper’s hawks abandon their nest if a human touches the eggs or chicks. In reality, birds have a poor sense of smell, and brief human disturbance rarely causes abandonment. However, prolonged disturbance—such as repeated visits or loud activity near the nest—can cause stress and may lead to nest failure.
Another issue is nest collapse, especially after heavy rain or wind. Because the nest is made of loosely piled sticks, it can fall apart, particularly if the supporting branch is weak. In urban areas, some nests are built on artificial platforms or even on building ledges, which can be problematic if the structure is unstable.
Predation of eggs and chicks is relatively rare, but raccoons, crows, and great horned owls may take them. Adult Cooper’s hawks are fierce defenders and will dive at intruders, including humans, if they approach the nest tree.
How to Observe a Nest Safely
If you find a Cooper’s hawk nest, the best approach is to observe from a distance using binoculars or a spotting scope. Stay at least 100 yards away, and never climb the nest tree or attempt to handle eggs or chicks. Use a car as a blind if possible, as hawks are less wary of vehicles.
It is also important to avoid visiting the nest during the first two weeks after hatching, when the female is most sensitive. If you see the adults giving alarm calls or diving at you, back away slowly—you are too close.
Comparison with Other Accipiters
Cooper’s hawks are often compared with the sharp-shinned hawk, which is smaller and has a squared-off tail, while Cooper’s tail is rounded. In terms of nesting, sharp-shinned hawks prefer denser conifer forests and build smaller nests, usually higher in the tree. Cooper’s hawks are more adaptable to open woodland and suburban areas.
The goshawk, a larger accipiter, nests in extensive boreal and montane forests and is much more secretive. Unlike Cooper’s hawks, goshawks are rarely seen in urban settings.
Frequently Asked Questions
Do Cooper’s hawks nest in the same place every year? Yes, they often reuse the same nest or build a new one within the same territory. A pair may have several alternate nests and rotate among them in different years.
When do baby Cooper’s hawks leave the nest? Chicks fledge at about 30 to 34 days after hatching, but they stay near the nest and depend on their parents for food for another month or more.
Will a Cooper’s hawk attack me if I get near its nest? Yes, they are protective parents. They may dive at your head or make loud alarm calls. It’s best to keep your distance and avoid the nest area during breeding season.
What should I do if a Cooper’s hawk nests in my yard? Enjoy the opportunity, but keep pets indoors and avoid using bird feeders that might attract prey near the nest. You can also put up a sign to warn visitors not to approach the nest tree.
How long does a Cooper’s hawk stay with its young after fledging? The young stay with the parents for about 4 to 6 weeks after leaving the nest, during which they learn to hunt. After that, they disperse to find their own territories.
Is it legal to remove a Cooper’s hawk nest? No, Cooper’s hawks are protected under the Migratory Bird Treaty Act. It is illegal to disturb or remove an active nest without a federal permit.
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