Ridgway’s Hawk is a smallish Buteo and, along with Red-tailed Hawk (Buteo jamaicensis), is one of only two Buteo hawks resident on the island of Hispaniola. Adults are similar in plumage: the back and breast gray, the belly and flanks streaked gray and white, the tarsi and toes are reddish, and the tail is gray, with 3 to 4 narrow white bands. Sexes are similar, but females are more brownish gray than are the males. Juveniles are dark brown above and cream or white below, while the plumage of immature Ridgway’s Hawk is similar to that of adults but is reddish brown where adults are gray.
There is one other resident, and two vagrant, Buteonine hawks on Hispaniola. Ridgway’s Hawk easily is separated from the resident species, Red-tailed Hawk (Buteo jamaicensis), by its smaller size, overall gray appearance, and gray tail with narrow white bands. Both of the other species recorded as vagrants, Broad-winged (Buteo platypterus) and Swainson’s (Buteo swainsoni) hawks, are larger with browner plumage and paler underparts.
Adult : Sexes similar. Back, head, nape, breast, and wings gray. Lower breast, flanks, and belly gray, with fine white bars. Tibial feathers rusty with white bars. Undertail coverts white, sometimes with rusty flecks. Upperparts of males tend to be more slaty than in females, and thighs slightly more rufous, although these differences are subtle.
Immature: Similar to adult, but plumage brown where adults are gray. Breast white, heavily barred rusty brown. Belly predominantly white. Head and nape brown, streaked white.
Ridgway’s Hawks molt in three phases. Fledglings begin to molt into their immature plumage (Preformative Molt) within months of leaving the nest. The molt into adult plumage (Second Prebasic Molt) begins the following year, with all individuals achieving adult plumage by sometime during their second summer. Females typically molt immediately after incubation and nesting.
Iris: dark brown.
Bill: maxilla and mandible gray, paler at the base.
Cere and eye ring: yellow.
Tarsi and toes: yellow.
In general, soft parts are yellowish green where adults are yellow.
Iris: dark golden yellow.
Total length: 36-41 cm (Latta et al. 2007)
Linear measurements: from Wiley and Wiley (1981).
male (n = 71)
wing length, mean 228.1 mm
tail length, mean 148.9 mm
culmen length, mean 18.3 mm
tarsus length, mean 66.2 mm
female (n = 10)
wing length, mean 244.9 mm
tail length, mean 160.5 mm
culmen length, mean 19.9 mm
tarsus length, mean 70.3 mm