Cooper’s Hawk – Complete Birding Guide

Of course. Here is a comprehensive, professional birding article about the Cooper’s Hawk, formatted for direct use in a WordPress publication.

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Mastering the Accipiter: A Field Guide to the Cooper’s Hawk (Astur cooperii)

A sudden flash of slate-gray and rufous, a frantic explosion of sparrows from a feeder, and then silence. For many backyard birdwatchers, this is their first introduction to the Cooper’s Hawk (Astur cooperii), a formidable and highly skilled avian predator. As a member of the genus Astur (the accipiters or “true hawks”), this species is a master of agile flight and surprise attacks. Its increasing presence in suburban landscapes has made it a familiar sight, yet it remains one of the most frequently misidentified birds of prey in North America. This guide provides a detailed look at the physical characteristics, field marks, and behaviors necessary to confidently identify this magnificent raptor.

Identification Features: Beyond a Simple Glance

Identifying a Cooper’s Hawk requires a careful assessment of its size, shape, plumage, and structure. Accipiters are notoriously difficult to separate, so focusing on a combination of features is crucial. The primary source of confusion is its smaller, more delicate cousin, the Sharp-shinned Hawk (Astur striatus).

Size and General Impression (GISS)

The Cooper’s Hawk is a medium-sized hawk, roughly the size of an American Crow, though it often appears leaner. It exhibits significant sexual dimorphism, with females being up to a third larger than males. This size difference can be so pronounced that a small male Cooper’s Hawk may approach the size of a large female Sharp-shinned Hawk, adding to the identification challenge.

• Overall Shape: The classic accipiter build features relatively short, broad, rounded wings and a very long tail. This body plan is an adaptation for high-speed, acrobatic pursuit through dense woodlands. In flight, it can look like a “flying cross.”
• Posture: When perched, it often stands upright, appearing powerful and purposeful.

Adult Plumage (2+ years old)

An adult Cooper’s Hawk is a strikingly handsome bird, defined by its contrasting colors and sharp patterns.

• Head: A key field mark is the dark gray or blackish cap that contrasts with a noticeably paler gray nape (the back of the neck). This gives the impression of wearing a distinct cap.
• Eyes: The eye color deepens with age, progressing from the juvenile’s yellow to a striking orange and finally a deep, ruby red in mature adults.
• Dorsal (Back and Wings): The back and upperwings are a uniform slate-blue or blue-gray.
• Ventral (Underparts): The breast and belly are white with fine, dense, horizontal rufous (reddish-brown) barring.
• Tail: The long tail is blue-gray above and pale below, marked with several wide, dark bands. Critically, the tail tip is broadly rounded and finished with a wide, white terminal band.

Juvenile Plumage (First Year)

Young Cooper’s Hawks look entirely different from adults and present their own identification challenges.

• Head: The head is brown, often with a less defined cap than the adult. A whitish supercilium (eyebrow line) may be visible.
• Eyes: The eyes are a pale yellow.
• Dorsal (Back and Wings): The upperparts are brown, often with pale mottling or edging on the feathers.
• Ventral (Underparts): The breast and belly are whitish or cream-colored, marked with thin, crisp, vertical brown streaks that resemble teardrops.
• Tail: The tail pattern is similar to the adult’s but is brown and buff instead of gray and black.

Key Differences: Cooper’s Hawk vs. Sharp-shinned Hawk

This is the ultimate accipiter identification test. Focus on structure and proportion, not just plumage.

• Head Projection: The Cooper’s Hawk has a large, blocky head that projects well beyond the leading edge of the wings in flight. The Sharp-shinned Hawk has a small, rounded head that barely projects, often looking “neckless.”
• Nape Color: The Cooper’s distinct dark cap and pale nape contrasts with the Sharp-shinned’s “hooded” appearance, where the dark gray of the head extends uniformly down the nape.
• Tail Shape: When folded, the Cooper’s Hawk’s tail feathers are of different lengths, creating a rounded appearance at the tip. The Sharp-shinned’s tail feathers are nearly all the same length, creating a squared-off or notched tip.
• Leg Thickness: If you get a good view of a perched bird, the Cooper’s has thick, powerful legs, sometimes described as being as thick as a pencil. The Sharp-shinned’s legs are remarkably thin, like toothpicks.
• Flight Style: The Cooper’s Hawk has a powerful, deliberate flight pattern: a few deep flaps followed by a glide (flap, flap, glide). The Sharp-shinned has a more buoyant, quick, and fluttery flight, like a large finch (flap-flap-flap, glide).

Habitat and Behavior

Historically a denizen of deciduous and mixed woodlands, the Cooper’s Hawk has adapted remarkably well to human-dominated environments. It is now common in suburban neighborhoods, city parks, and farmlands, provided there are mature trees for nesting and perching. This adaptability is largely driven by the abundance of its preferred prey.

As a quintessential bird-eater, its diet consists mainly of medium-sized birds such as Mourning Doves, European Starlings, Blue Jays, and American Robins. They are also opportunistic and will take small mammals like chipmunks and squirrels. Their hunting strategy is one of stealth and explosive speed, often bursting from cover to surprise prey at bird feeders or in open lawns. Their distinctive “cak-cak-cak” alarm call is most often heard near a nest site during the breeding season.

Best Viewing Tips

Observing a Cooper’s Hawk can be both a planned and an opportunistic event.

• Time and Season: They are present year-round in much of the United States. The fall migration (September-November) and spring migration (March-May) are excellent times to see them in numbers at established hawk watch sites.
• Location: Pay close attention to your backyard bird feeders; this is the number one spot for suburban sightings. Also, scan the edges of wooded areas, parks with tall trees, and riparian corridors.
• Behavioral Cues: The most reliable way to find a Cooper’s Hawk is to listen. The frantic, high-pitched alarm calls of jays, robins, and chickadees often signal that a hawk is perched nearby. A sudden, complete silence at a busy feeder is another dead giveaway.

Photography Tips

Capturing a quality image of this swift raptor is a rewarding challenge.

• Equipment: A telephoto lens (400mm or longer) is essential to get frame-filling shots without disturbing the bird.
• Settings: Use a very fast shutter speed (1/1600s or faster) to freeze the action, especially for flight shots. Open your aperture (e.g., f/5.6-f/8) to gather light and create a soft background. Use continuous autofocus (AF-C) to track the moving bird.
• Technique: Patience is key. Often, the best shots come from waiting near a known hunting perch or a bird feeder. Use your vehicle as a blind; hawks are often less wary of cars than of people on foot. Always prioritize the bird’s welfare over the photograph.

Conservation Status

Like many birds of prey, Cooper’s Hawk populations suffered severe declines in the mid-20th century due to the pesticide DDT, which caused eggshell thinning. Following the ban of DDT in 1972, the species has made a remarkable comeback. The International Union for Conservation of Nature (IUCN) lists the Cooper’s Hawk as a species of “Least Concern,” with a stable and likely increasing population.

Their success is a testament to their adaptability. However, they still face modern threats, including collisions with windows (a common hazard during high-speed pursuits) and potential secondary poisoning from rodenticides. By understanding and appreciating this incredible predator, we can better coexist and ensure its continued success in our shared landscapes.