Taxonomy & Identification

Scientific name: Astur cooperii (formerly Accipiter cooperii).
Family: Accipitridae (hawks, eagles, kites).
Appearance: Medium-sized raptor, 35–50 cm in length, with short rounded wings and a long, banded tail. Adults have bluish-gray upperparts and reddish-barred underparts; juveniles are brown with streaked underparts.
Sexual dimorphism: Females are larger than males (typical of raptors).

Distribution & Habitat

Range: Native to North America, breeding across southern Canada, throughout the continental U.S., and into northern Mexico.
Habitat: Prefers woodlands, forest edges, riparian zones, and increasingly suburban/urban areas with mature trees.
Nesting: Builds large stick nests high in deciduous or coniferous trees, often reusing old nests.

Primary diet: Medium-sized birds (doves, pigeons, starlings, jays, robins, sparrows).
Secondary prey: Small mammals (squirrels, chipmunks, mice), and occasionally reptiles and insects.
Hunting style: Ambush predator; uses cover and agility to weave through trees, surprising prey with rapid, short-burst chases.
Urban adaptation: In cities, diets shift toward abundant prey around bird feeders (e.g., Mourning Doves, Rock Pigeons, House Sparrows).

Breeding season: Late spring through summer.
Clutch size: 2–5 eggs, incubated mainly by the female.
Fledging: Young leave the nest at about 4–5 weeks, dependent on parents for another month.
Longevity: Many fall victim to window strikes and vehicle collisions in urban areas, though individuals can live over 10 years in the wild.

Population control: Plays a key role in regulating populations of medium-sized birds. This helps prevent ecological imbalances, especially in areas where prey species (like pigeons or starlings) can become overly abundant.
Influence on prey behavior: Creates a “landscape of fear” that alters the foraging and flocking patterns of songbirds. Birds at feeders, for instance, will often adjust vigilance and feeding times in response to hawk presence.

Cooper’s Hawks frequently prey on doves and pigeons, which are carriers of Trichomonas gallinae, a protozoan parasite. This link creates a strong predator–prey–pathogen relationship:
- Infected prey can transmit disease to hawk nestlings through regurgitated food.
- Outbreaks of trichomoniasis have caused significant nestling mortality in some urban populations.
This makes Astur cooperii an important species for studying how predators, prey, and pathogens interact in city ecosystems.

Adaptability: Once considered shy woodland hawks, they now thrive in urban and suburban landscapes. Cities like Chicago, Tucson, and New York have stable and growing populations.
Synanthropy: Their success is tied to human activities such as bird feeding, which concentrates prey, and urban tree planting, which provides nesting sites.
Behavioral innovation: Studies have documented hawks timing hunts with human movement (e.g., using traffic or pedestrians as cover), showing high cognitive flexibility.

As predator: Controls prey populations, maintaining balance in avian communities.
As prey: Nestlings and eggs are vulnerable to raccoons, crows, and snakes; adults may be taken by larger raptors such as Great Horned Owls.
As host: Serves as a host for parasites (lice, tapeworms, helminths), supporting broader parasite and scavenger networks.

IUCN Red List: Least Concern, with increasing population trends.
Historical context: Populations declined during the mid-20th century due to DDT and persecution but rebounded after pesticide bans and legal protection under the Migratory Bird Treaty Act.
Present threats: Collisions (windows, cars), secondary poisoning from rodenticides, and disease outbreaks in urban settings.

Bird feeding: Regular cleaning of feeders can help limit disease transmission among prey species, which in turn supports hawk health.
Window safety: Installing strike deterrents (UV decals, screens, patterned glass) reduces accidental hawk and songbird deaths.
Rodenticides: Avoidance of second-generation anticoagulant rodenticides prevents secondary poisoning.
Urban biodiversity: Planting native trees and maintaining green corridors provide nesting habitat and sustain prey diversity.