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.
SPECIFIC DESCRIPTION
The many variations of plumage within each subspecies result in birds that may be difficult to assign to a race on the basis of plumage. The following descriptions refer to recognizable forms, with comments about taxonomic association where appropriate. In particular, western forms may not be safely assignable to subspecies from plumage descriptions. The sexes are alike except for size, although females average larger.
Adult Western (calurus) Light-morph - Perched
Note: The "Western" Red-tailed Hawk (calurus) is highly variable and have as many as three color morphs. The range of variation amongst individuals seems to bridge the "color morphs" due to interbreeding. The color morphs are generally referred to as light, rufous and dark but variations are legion. As well, some of the color morphs discussed under this subspecies may in fact be representative of the extremes of some other subspecies as intergrades approach one another.
The basic plumage is often described as being like the eastern Red-tail with some specific variations, so the description for the "Eastern" Red-tailed Hawk (borealis) is presented here with modifications as appropriate and as available from literature.
HEAD
- generally brown over the sides and top giving a "hooded" appearance
- a blackish mustache mark is usually present at the sides of the chin
- chin and throat white in the center but streaked with brown on the sides and often darker than in the "Eastern" Red-tailed Hawk (borealis)
- forehead may or may not have much whitish feathering
- the lores are whitish
- the beak is blackish but grades to bluish near the base
- the cere is yellow
- the eye is brown with a dark pupil
BODY
- the upper breast through to the tail is more rufous than white with variable amounts of dark markings but usually more than the "Eastern" Red-tailed Hawk (borealis)
- these markings often become extensive and form a dark "belly band" that may be absent but is usually more extensive than in eastern birds
- the flanks are barred
- the back and upperparts are dark browns with white markings that may form a "V"
WINGS
- the upper wings are similar to the back but some coverts may have whitish edgings
- the primaries are dark but some light barring may be evident and they do reach the end of the tail in this race
TAIL
- the underside is a washed out rufous color with faint dark banding near the tip
- the upperside is rufous to deep red often with 7 to 10 narrower dark bands and a wider black band near the whitish tip
LEGS
- the legs and feet are yellow to olive yellow
- the talons are black
Immature Western (calurus) Light-morph - Perched
Overall, the brown colors are darker than those of the "Eastern" Red-tailed Hawk (borealis)
HEAD
- much of the head is a medium, neutral brown paler than adults'
- the mustache mark may be obscure or absent
- the chin and throat are darkly streaked to all dark
- the lores are whitish
- a whitish spot on the rear crown may be visible
- the beak is blackish at the tip and a lilac gray basally
- the cere is light greenish to olive-buff
- the iris is dull yellow to brownish cream
BODY
- the underparts are all white from the chin to the tail
- elongated black markings form a belly band
- the back is dark brown with white mottling that can form a "V"
- the leg feathering usually has brown barring
WINGS
- the upper coverts are dark brown
- the scapulars may show buff to white markings
- the primaries are variably grayish or dark
TAIL
- from below it is a dingy brown
- from above, the tail is grayish brown with numerous dark transverse bars and a white tip
LEGS
- the legs and feet are dull to greenish yellow
- the talons are black
SIMILAR SPECIES
Depending upon age, race and color morph, the Red-tailed Hawk could be mistaken for similar variants of Swainson's, Ferruginous, Rough-legged, Red-shouldered, Broad-winged, and perhaps Short-tailed hawk. the Red-tailed Hawk does not soar with its wings in a dihedral as do the Swainson's Hawk and the wings are wider at the base, giving the bird a much stockier appearance. Assuming good views of these similar species are obtained, separation may be organized as follows:
Light-morph Adults
- the upper surface of the tail is rufous-colored, unlike any other light plumaged buteo except the Ferruginous Hawk. This latter species also has a rufous-colored back and reddish tarsal feathering that are not characteristic of any other light buteo. The Red-tailed Hawk also has whitish underwings with black tips and dark patagial marks, unlike any other buteo. "Krider's" Red-tailed Hawk (krideri) does not have the reddish tarsal feathering of the Ferruginous Hawk.
Dark-morph Adults
- dark western or rufous morphs of the Red-tailed Hawk usually has some degree of reddish coloring in the tail which is not present in dark morphs of other buteos. The tail of "Harlan's" Red-tailed Hawk (harlani) is more variable and may have rufous near the tip or appear more blackish or narrowly dark and white banded. This latter race may also have some whitish streaking on the breast set against a generally black body, further distinguishing it from Common Black-Hawk, Zone-tailed Hawk or the dark Rough-legged Hawk.
Immatures
- immature, light-plumaged birds retain the dark "patagial" mark on the underwing that is not found on the Red-shouldered, Broad-winged, Swainson's, or White-tailed hawk. Immatures of the "Krider's" Red-tailed Hawk (krideri) have the dark "patagial" marks. Immature Red-tailed Hawks all have a distinct light panel, or "window", on the upper primary and primary greater coverts which is shared by no other buteo species. Dark-morph immature Red-tailed Hawks usually have light breast markings and many dark bands on the brown tail. The immature Zone-tailed Hawk is more blackish with white spots on the underbody and the immature Common Black-Hawk has more tawny feathering on the breast with dark streaking, dark flank patches, and a patterned head.
OTHER NAMES
The Red-tailed Hawk is also referred to as the "Eastern Red-tailed Hawk", "Florida Red-tailed Hawk", "Fuertes Red-tailed Hawk", "Harlan's Hawk", "Krider's Hawk", "Western Red-tailed Hawk", "Buzzard", "Chicken Hawk", "Gopher Hawk", "Hen Hawk", and "Redtail."
ETYMOLOGY
The genus Buteo is Latin for "buzzard" which is an early name for hawks and vultures. The species name jamaicensis is the Latin word for the locality where the first individual was described. Red-tailed clearly refers to one of the commonly seen field marks and Hawk is likely from the Teutonic word "hab" meaning to "sieze."
MYTHOLOGY
There is none documented for North America.
VOICE
The common call is a down-slurred scream given in flight or from a perch. Sometimes described as "tsee-eee-arrr", it is hoarse, sibilant and may vary in pitch, reminding one of a cat scream at greater distances. The function is likely territorial. Following a territorial encounter, individuals of mated pairs will utter a loud "chwirk" call. Other notes include a series of low, raspy "hrrrr" sounds, grunting or quacking "gank" calls and hunger calls similar to those of the nestlings. During courtship, a loud "chirk-chirk-chiruk" is given but perhaps this is the "chwirk" of other authors. The young utter soft, peeping notes and as they grow, softer versions of the adult scream as well as two-syllable "klee-uck" calls are given.