The Red-tailed Hawk occupies a wide range of habitats and altitudes, including deserts, grasslands, coniferous and deciduous forests, tropical rainforests, agricultural fields and urban areas. It lives throughout the North American continent, except in areas of unbroken forest or the high arctic. It is legally protected in Canada, Mexico and the United States by the Migratory Bird Treaty Act.
Because they are so common and easily trained as capable hunters, the majority of hawks captured for falconry in the United States are Red-tails. Falconers are permitted to take only passage hawks (which have left the nest, are on their own, but are less than a year old) so as to not affect the breeding population. Adults, which may be breeding or rearing chicks, may not be taken for falconry purposes and it is illegal to do so. Passage red-tailed hawks are also preferred by falconers because these younger birds have not yet developed adult behaviors, which will make training substantially more challenging.
A male Red-Tailed Hawk may weigh from 690 to 1,300 g (24 to 46 oz), with a mean weight of 1,030 g (36 oz), and measure 45–60 cm (18–24 in). A female can weigh between 900 and 2,000 g (32 and 71 oz), averaging 1,220 g (43 oz), and measure 48 to 65 cm (19 to 26 in) long. The wingspan can range from 105 to 141 cm (41 to 56 in) and, in the standard scientific method of measuring wing size, the wing bone is 33–44 cm (13–17 in) long. The tail measures 19–25 cm (7.5–9.8 in) in length. The exposed culmen was reported to average 2.5–2.7 cm (0.98–1.06 in) and the tarsus averaged 8.6–9 cm (3.4–3.5 in). As is the case with many raptors the Red-tailed Hawk displays sexual dimorphism in size, as females are up to 25% larger than males.
Red-tailed Hawk plumage can be variable, depending on the subspecies and the region. These color variations are morphs, and are not related to molting. The western North American population, B. j. calurus, is the most variable subspecies and has three color morphs: light, dark, and intermediate or rufus. The dark and intermediate morphs constitute 10–20% of the population.
Though the markings and hue vary across the subspecies, the basic appearance of the Red-tailed Hawk is consistent. Overall, this species is blocky and broad in shape, often appearing (and being) heavier than other Buteos of similar length. A whitish underbelly with a dark brown band across the belly, formed by horizontal streaks in feather patterning, is present in most color variations.
Especially in younger birds, the underside may be otherwise covered with dark brown spotting. The red tail, which gives this species its name, is uniformly brick-red above and light buff-orange below. The bill is short and dark, in the hooked shape characteristic of raptors, and the head can sometimes appear small in size against the thick body frame. They have a relatively short, broad tails and thick, chunky wings. The cere, the legs, and the feet of the Red-tailed Hawk are all yellow.