Cooper’s Hawks belong to the genus Accipiter and are widespread throughout North America, including Canada and Mexico. These compact, crow-sized hawks are exceptionally fast and agile and make their home in various habitats ranging from mountain ranges to semi-arid deserts.
Similar to most birds of prey, female Cooper’s hawks are considerably larger than the males - this is a guide to female Cooper’s hawks.
First and foremost, female Cooper’s hawks are much, much larger than males - up to 20% longer and 40% heavier. This is amongst the most pronounced reverse sexual dimorphisms of any bird. Besides size, male and female Cooper’s hawks look similar, though females are more brownish and grayish, and males are often a subtle powder-blue color across the wings and back.
When a size comparison between males and females isn’t possible, the next best place to look is the eyes. Male Cooper’s hawks have dark eyes, often a dark orange, whereas females have light yellow or light orange eyes. In some cases, males have overall brighter plumage than females, but plumage isn’t a consistent way to tell the birds apart.
Male and female Cooper’s hawks have a number of complex interactions, and their different behaviors make it easier to identify them. Read on to learn more about female Cooper’s hawks and how to identify them from females.
Size is one of the best ways to tell male and female Cooper's Hawks apart, with females being considerably larger
Adult Cooper's hawks are medium-sized, compact raptors with shortish wings. They're about the size of a large crow, though the female can be 1/3rd bigger than the male.
In terms of color and plumage, Cooper's hawks are brown-gray to blueish on their upper wings and backs. Their heads and crowns are quite square and boxy, consisting of dark brown or blackish feathers above a pale nape and neck. The chest and breast are paler, with brown banding. The tail has three blackish bands but is otherwise paler than the back.
A female Cooper's hawk can be distinguished from a male by its considerably larger size and slightly less distinctly marked plumage, though this does vary. The back of a female Cooper's hawk is usually more gray or brown, and less likely to be blue. Some male hawks have powder-blue backs that are completely absent from females. Chest barring may also be brighter and more defined.
In general, female Cooper's hawks are larger and more brown-gray than the more blueish males. Moreover, females have lighter eyes which are more yellow than orange. On the other hand, adult males have considerably darker orange eyes.
Cooper's Hawk on the ground
In contrast to most birds, female raptors are typically larger than the males, and Cooper’s hawks are no different.
Female Cooper’s hawks are up to 1/3rd larger than males. They’re some 20% longer than 40% heavier, and the difference is hard to miss when males and females are side-by-side. This is one of the most prolific examples of reverse sexual dimorphism.
The total length of adult Cooper’s hawks varies from 35 to 46 cm (14 to 18 in) in males and 42 to 50 cm (17 to 20 in) in females. Wingspan ranges between 62 to 99 cm (24 to 39 in). One study found that males weighed around 280g (9.9 oz) on average, whereas females weighed around 473 g (1.043 lb). There is virtually no overlap between males and females - females are consistently larger, regardless of regional variations.
There are no specific names for female Cooper's Hawks.
Juvenile Cooper's Hawk in flight
The main way to tell if a Cooper’s hawk is male or female is by comparing their size. Females are considerably larger than males, with almost no overlap between their size and weight ranges, even when accounting for regional variation.
Besides sheer size, male Cooper’s hawks have brighter, more heavily contrasting plumage than the females. They’re also more likely to be blue-gray rather than brown. This shows that sexual dimorphism in Cooper’s hawks probably evolved for the purpose of enhancing the female’s survival, as the male still has brighter plumage to attract females.
Other than size, there are a few other ways to tell the difference between differentiate between male and female Cooper's Hawks, particularly by some of the behavior exhibited.
Below, we go into more detail on other ways to tell the difference between the two.
Close up portrait of a Cooper's Hawk
When forming pair bonds, male Cooper’s hawks are submissive to females. Rather than approaching females directly, females sing a reassuring song to a nearby male to indicate they’re open to being approached.
Males often bow after a complex flying courtship ritual. Once bonded, the male will build most of the nest, which also forms part of courtship. In Wisconsin, the male built around 70% of the nest, with the female providing some materials and inspecting its construction.
The male flies to the female to copulate. After copulation, the female will prepare to lay her clutch as the male begins to hunt. The female incubates the eggs while the male hunts, feeding both the female and the young chicks once they hatch. The female also joins to hunt once the chicks are more than a couple of weeks old. Roles do sometimes interchange - one study found the male takes control of incubation for short periods while the female hunts.
Female Cooper’s hawks rip up the prey the male delivers and feeds it to their chicks whole. The female’s larger beak makes her more efficient at tearing up prey, which is thought to be one of the reasons why females are larger than males.
Close up of a nesting Cooper's Hawk
Female hawks are dominant and hunt different prey to males. Females are capable of hunting much larger prey such as larger birds and land mammals.
This confers survival advantages, as male and female Cooper’s hawks compete less over food and are able to diversify their hunting to take advantage of what’s available in their habitat.
Female Cooper’s hawks have over 40 vocalizations and calls in their repertoire, which is considerable amongst raptors. Contrastingly, males have around 20 calls, many of which are quieter and higher pitched than the female. This differs to birds where reverse sexual dimorphism doesn’t occur - it’s usually the male that sings more frequently than the female.
Female Cooper’s hawks are louder and harsher than the higher-pitched males. They have a number of unique calls, including a softer reassuring call to indicate males they’re ready to be approached for breeding.
Overall, females lead communications between Cooper’s hawks, instructing males on various tasks associated with breeding and rearing the chicks.
Cooper's Hawk with freshly caught prey
Female Cooper’s hawks tend to migrate first, around a week earlier than males in some studies.
Female Cooper’s hawks rely on close cooperation from the male to raise young.
The male builds most of the nest, and guards the nest during incubation. While the female incubates, the male delivers food to her and to the chicks when they hatch. Males help raise the chicks through until independence.
If the male hawk were to die sometime during incubation, it’d be highly unlikely that the nest will succeed.
Female Cooper’s hawks have roughly double the number of calls as the male. The female is also louder, with a deeper, harsher voice.
Females lead communications between Cooper’s hawks, especially during the breeding season.
One of the most distinct female-specific calls is a whaa, which the female uses to signal the male she or the chicks need food. The male also has some specific calls, including a high-pitched kik that he uses to find his mate.
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