The Cooper’s Hawk (Accipiter cooperii) is a widespread North American raptor frequently observed in wooded areas and suburban backyards as it hunts for prey. This medium-sized bird of prey belongs to the Accipiter group, known for their agility, short, rounded wings, and long tails, which allow for rapid maneuvering flight through dense cover. The species historically faced severe population challenges, leading many to question its conservation status. Understanding the Cooper’s Hawk requires examining its physical traits and the environmental crisis it survived, and appreciating its successful recovery.
Identifying the Cooper’s Hawk
The adult Cooper’s Hawk features a blue-gray back, a dark cap, and a chest covered in fine reddish-orange horizontal barring. Its body length ranges from 14 to 20 inches, and females are noticeably larger than males, a common trait among raptors. The long tail acts as a rudder, allowing the hawk to navigate quickly through forest canopies while pursuing birds and small mammals.
Distinguishing the Cooper’s Hawk from the smaller Sharp-shinned Hawk (Accipiter striatus) can be difficult, as they share a similar color pattern. Cooper’s Hawks are roughly the size of a crow, while Sharp-shinned Hawks are closer to the size of a jay. However, a more reliable field mark is the Cooper’s Hawk’s proportionally larger, block-like head, which projects prominently past the wings during flight. Additionally, the Cooper’s Hawk’s tail appears rounded at the tip, unlike the squared-off tail of the Sharp-shinned Hawk.
Historical Decline and the DDT Crisis
The Cooper’s Hawk population experienced a severe decline across North America in the mid-20th century, reaching its lowest numbers between the 1940s and 1970s. This collapse was directly linked to the widespread use of organochlorine pesticides, particularly DDT (Dichlorodiphenyltrichloroethane), employed extensively for agricultural and insect control. These chemicals entered the environment and bioaccumulated in the food web, impacting predators like the Cooper’s Hawk.
The primary harm was a sublethal effect on reproduction, not immediate death. When hawks consumed contaminated prey, DDT’s metabolite, DDE, built up in their tissues. DDE interfered with the female hawk’s ability to metabolize calcium necessary for eggshell formation. The resulting eggshells were substantially thinner and more fragile, often cracking under the weight of the incubating parent. This reproductive failure led to widespread nesting loss and a dramatic drop in the population.
The species also faced historical persecution from shooting and trapping before legal protections were implemented. This combination of factors pushed the Cooper’s Hawk toward possible regional extinction in many parts of its range.
Current Conservation Status and Widespread Recovery
The Cooper’s Hawk is not endangered and represents a successful conservation story. The species is now classified as “Least Concern” by the International Union for Conservation of Nature (IUCN), reflecting its stable and increasing population. This recovery began in 1972 when the use of DDT was banned in the United States, removing the primary threat to the species’ reproductive health.
The removal of DDT allowed for the restoration of proper eggshell thickness, boosting nesting success and chick survival rates. Further protection was provided by legislation, such as the Migratory Bird Treaty Act, which prohibits the hunting, capturing, or killing of the species. This legislative protection, combined with the chemical ban, created the necessary conditions for population rebound.
A factor in the hawk’s successful recovery has been its adaptability to human-altered landscapes. Once primarily a forest-dwelling bird, the Cooper’s Hawk now exploits urban and suburban environments for hunting and nesting. They frequently utilize mature trees in parks, residential neighborhoods, and city centers to build their nests.
While the species is thriving, it still faces modern challenges related to its close proximity to human infrastructure. The most frequent cause of mortality in urban areas is collisions, particularly with windows and motor vehicles. Researchers continue to monitor the population through surveys, confirming a moderate increase in numbers since the 1970s.