If there is an archetypal buteo, then, perhaps the Red-tailed Hawk is it. This widespread hawk is a large, comparatively broad-winged soaring species that occupies a wide range of habitats. The average wingspan is about four feet (1.24 meters) and the average length is just under two feet (0.62 meters). Plumage variation is great but in very general terms. There are light-morph birds that have brown backs and red tails with whitish underparts variously marked with dark streaking, and there is another large group of dark-morph birds that are dark brown to blackish colored all over the body and upper wings with two-toned light and dark underwings and tails that vary from rufous through to whitish gray with dark bands. An enormous range in plumage variation occurs across the range of this species with intergrades and degrees of intensity resulting in perhaps the most complex raptor in North America to identify correctly at the subspecific level, and occasionally, at the species level.
The "Western" Red-tailed Hawk has light, rufous, and dark-morphs, the "Harlan's" has light but predominantly dark-morphs, the "Eastern" has only la ight-morph, the "Krider's" is a pale variant of the "Eastern" race, the "Florida" , and "Fuertes", and Alaska" Red-tailed Hawk all have only a light-morph.
SIZE
The Red-tailed Hawk is one of the largest buteos, with a wingspan ranging from 43 to 56 inches (109.2 to 142.2 centimeters) depending upon the sex, population or author you are dealing with. Females are larger than males and vary in length from 20.5 to 25 inches (52.1 to 63.5 centimeters) with wingspans up to 56 inches (142.2 centimeters). It weighs from 32 to 50 ounces (914 to 1,429 grams). Males vary in length from 18 to 22.5 inches (45.7 to 57.2 centimeters) with wingspans up to 45 inches (114.3 centimeters). It weighs from 27 to 39 ounces (771 to 1,114 grams).
Eastern birds tend to have wingspans ranging from 43 to 52 inches (109.2 to 132.1 centimeters) and average 47 inches (119.4 centimeters) while western populations range from 47 to 56 inches (119.4 to 142.2 centimeters) and average 51 inches (129.5 centimeters).
MORPHS AND MOLTS
This is a highly variable species with light, rufous, and dark-morphs. Only the "Western" Red-tailed Hawk has morphs, the rest are subspecies except the "Harlan's" Red-tailed Hawk. There is great variation due to interbreeding. The question of taxonomy in this species still appears to be confused and it is not safe to say that certain subspecies are dark while others are light, as each taxonomic grouping appears to have plumage variations that may fit into any of these color morphs. The rufous and dark-morph only breed in the West, that is west of the Rocky Mountains. Subspecies are found within a fairly specific range with overlap at the fringes.
The juvenile plumage is retained for nearly a year with the molt into adult plumage starting during the following breeding season. Molt into the adult plumage takes about 100 to 120 days and is complete by early fall of the second calendar year. Thus "adult" birds first start appearing at about 1.5 years of age.
