Hawks, birds of prey with short hooked bills and powerful claws, are all members of the order Falconiformes. The most common type of hawk in North America is the red-tailed hawk, a striking-looking bird with cocoa-colored back feathers, a pale underbelly, and a reddish tail. Other varieties of hawk include sharp-shinned hawks and red-shouldered hawks, commonly called chicken hawks. Telling male and female hawks apart is very difficult, because both sexes exhibit identical plumage. Even scientists have a hard time differentiating between the sexes; in order to be positive of a hawk's gender, they have to analyze the feathers for sex-specific DNA markers. However, there are some behavioral and size differences between male and female hawks; by using your powers of observation, you can make an educated guess.
Identify the female hawk by her larger size—usually 25 to 35 percent larger than the male—when you see a pair of hawks together. Hawks exhibit reverse sexual size dimorphism—a fancy way of saying that adult males are smaller than adult females. Hawks do not gather in flocks, but they are monogamous and often mate for life. When you see two hawks together, the chances are excellent that they are an established pair.
Identify the female hawk sitting on, or brooding, the nestlings, if you are lucky enough to be able to observe hawks in their nest. Sitting on the eggs is not proof positive of a female hawk, since male hawks also help to incubate the eggs. Only the female, however, broods the young.
Watch for a hawk returning to the nest with prey in his talons for the female and chicks—this will be the male, who will faithfully supply his family with food for at least six weeks.
Observe the hawks' courtship ritual for a foolproof way to tell the male hawk from the female. Courting males do a "sky dance", soaring high, then plummeting straight down and spiraling upwards quickly. The hawks then lock talons, and plummet towards the earth together; at one point, however, the male will fly over the female and grasp her briefly from above.
Use your ears to identify the female hawk. Females sometimes give a "wailing" type call that is not in the male hawk's repertoire. Juvenile hawks perform a more high-pitched version of this call when they are hungry. Both male and female hawks will sound an identical "kih-kih-kih" alarm call if you—or any intruder—get too close to the nest.
Watch for courtship feeding—if one hawk presents a larger hawk with a snake or rabbit, you have just witnessed a courtship gift, and the giver is male.