<Li> B. j. fuertesi (southwestern red - tailed hawk) breeds from northern Chihuahua to southern Texas . It winters in Arizona, New Mexico, and southern Louisiana . This seems to be a particularly large subspecies, although its size is not drastically different from calurus, and, going on average wing size and tarsal length, this appears to be the largest race of red - tailed hawk . The wing chord of males can range from 385 to 402 mm (15.2 to 15.8 in), averaging 393.3 mm (15.48 in), and, in females, it ranges from 425 to 436 mm (16.7 to 17.2 in), averaging 430.7 mm (16.96 in). Additionally, males and females average 210.9 and 223.8 mm (8.30 and 8.81 in) in tail length, 88 and 93 mm (3.5 and 3.7 in) in tarsal length and 26.3 and 27.5 mm (1.04 and 1.08 in) in culmen length . Hybridization seems to occur in eastern Texas with borealis, broadly to west with calurus and, possibly, Nuevo León - Chihuahua with B. j. hadropus . This race combines the darker back of calurus with the paler underside of borealis, with the belly - band either entirely absent or only manifesting in light streaking . The tail is variable but relatively pale, with some individuals showing almost no dark subterminal band, others having quite a broad subterminal band and some showing extensively barring on top like darker morphs of calurus . </Li> <Li> B. j. fumosus, Islas Marías, Mexico . A relatively small subspecies . Unlike some other island races, the validity of this race has rarely been called into question . The wing chord of males can range from 368 to 370 mm (14.5 to 14.6 in), averaging 369.3 mm (14.54 in), and, in females, it ranges from 395 to 400 mm (15.6 to 15.7 in), averaging 397.4 mm (15.65 in). Males and females average 228.9 and 235.5 mm (9.01 and 9.27 in) in tail length, 85.9 and 88.3 mm (3.38 and 3.48 in) in tarsal length and 27.4 and 29.2 mm (1.08 and 1.15 in) in culmen length . This race is similar to calurus but, beyond being noticeably smaller, is duskier and duller hued overall and has a more cinnamon wash below, with heavily dark barred thighs . </Li> <Ul> <Li> B. j. hadropus, Mexican Highlands . Not all authorities recognize this race, however most list as it as valid in recent years . Like other neotropical races, this one is relatively small . wing chord averages 378.9 mm (14.92 in) in males and 401.1 mm (15.79 in). Males and females average 215 and 230.4 mm (8.46 and 9.07 in) in tail length, 89.1 and 88 mm (3.51 and 3.46 in) in tarsal length and 26.3 and 26.8 mm (1.04 and 1.06 in) in culmen length . Apparently, this is a similarly race as to B. j. kemsiesi to the south but unlike that race it has rufous barring that extends to the flanks and belly . Apparently, some dark morphs have occurred . One other unique feature is its massive feet (as implied in the subspecies' scientific name), with a toe length nearly 10% longer than calurus despite its otherwise small body size . The evolutionary reason for these relatively large feet are not known . </Li> <Li> B. j. harlani (Harlan's red - tailed hawk, It breeds from central Alaska to northwestern Canada, with the largest number of birds breeding in the Yukon territory or western Alaska, reaching their southern limit in north - central British Columbia . The Harlan's hawk is restricted as a breeder to pure taiga habitat . Harlan's hawk winters from Nebraska and Kansas to Texas and northern Louisiana, with a rare bird found as far east as Tennessee . While similar in linear dimensions to calurus, this race is sometimes described as slighter and lighter than typical western red - tailed hawks . On the contrary, though, they are highly sexually dimorphic in size (the most dimorphic of any in the United States) and mature females are not infrequently notably more massive and heavy than almost any female calurus . However, calurus tends to have a much longer tarsus than Harlan's hawks do, as expected due to the latter's habitation of cold environments almost year around . The wing chord of males can range from 365 to 390 mm (14.4 to 15.4 in), averaging 381 mm (15.0 in), and, in females, it ranges from 390 to 430 mm (15 to 17 in), averaging 408.7 mm (16.09 in). Males and females average 211 and 225.3 mm (8.31 and 8.87 in) in tail length, 79.8 and 87 mm (3.14 and 3.43 in) in tarsal length and 24.7 and 27 mm (0.97 and 1.06 in) in culmen length . A wintering female in eastern Kansas weighed 1,629 g (3.591 lb). The historic taxonomic status of Harlan's hawk has been quite erratic, sometimes it has been classified as its own species, B. harlani to the opposite extreme that Palmer (1988) classified as it (perhaps improbably) as a mere western color morph . Most modern authorities recognize as a valid subspecies . Harlan's hawk is markedly different from all other red - tails and can reportedly be identified nearly 100% of the time by an experienced hawk - watcher . In both color morphs, the plumage is predominantly blackish, lacking any warmer or brownish tones (save the tail). Harlan's hawks usually have faint streaks on the sides of their head and a little gray mottling or speckling on scapulars . Apart from a variably white - streaked throat, their underparts usually mostly black with variable white streaking and barring on the thighs or crissum . There are up to four main variations from the typical one above: extreme dark morph (where even throat is black and no pale streaking is present), dark morph (with barring still present from tarsus to underside), rare pale morph (with few blackish blobs on belly and generally whiter head) and perhaps even rarer types where the base color is grayish . Unlike most red - tailed hawks, generally immatures are similar enough to adults that it can be difficult to distinguish them . On average, immatures have more extensive pale streaking above and mottling below, but much individual variation has been recorded . The typical tail of a Harlan's hawk is white with a thick black subterminal band but individuals may vary considerable and the tail may be reddish, dusky, whitish, or gray and can be longitudinally streaked, mottled, or barred . </Li> <Li> B. j. kemsiesi is a dark subspecies resident from Chiapas, Mexico to Nicaragua . The wing chord of males can range from 357 to 382 mm (14.1 to 15.0 in), averaging 376 mm (14.8 in), and, in females, it ranges from 362 to 402 mm (14.3 to 15.8 in), averaging 398.2 mm (15.68 in). Males and females average 212.5 and 231 mm (8.37 and 9.09 in) in tail length, 87.8 and 87.1 mm (3.46 and 3.43 in) in tarsal length and 26.1 and 26.4 mm (1.03 and 1.04 in) in culmen length . This race is similar to B. j. fuertesi but markedly smaller, with its thighs barred with rufous . The dark wing marking may not be distinct in paler birds . A dark morph, similar to calurus, is known to occur in this race . </Li> </Ul> <Li> B. j. hadropus, Mexican Highlands . Not all authorities recognize this race, however most list as it as valid in recent years . Like other neotropical races, this one is relatively small . wing chord averages 378.9 mm (14.92 in) in males and 401.1 mm (15.79 in). Males and females average 215 and 230.4 mm (8.46 and 9.07 in) in tail length, 89.1 and 88 mm (3.51 and 3.46 in) in tarsal length and 26.3 and 26.8 mm (1.04 and 1.06 in) in culmen length . Apparently, this is a similarly race as to B. j. kemsiesi to the south but unlike that race it has rufous barring that extends to the flanks and belly . Apparently, some dark morphs have occurred . One other unique feature is its massive feet (as implied in the subspecies' scientific name), with a toe length nearly 10% longer than calurus despite its otherwise small body size . The evolutionary reason for these relatively large feet are not known . </Li>

Where do red tail hawks sleep at night