Excerpt
NORTHERN GOSHAWK Pl. 13 Accipiter gentilis
Description The Northern Goshawk, our largest accipiter, is a breeding resident in northern and western mountain forests. Wings are long for an accipiter, rather buteo-like. Tip of folded tail is wedge-shaped. Sexes are almost alike in plumage, with females separably larger than males. Juvenile plumage is different from that of adults. Cere is greenish yellow to yellow. Legs are yellow. On perched birds, wingtips extend halfway to tail tip. Widespread race atricapillus is described below.
ADULT: Head is black except for wide white superciliary lines and whitish throat. Eye color varies from orange to red to mahogany, darkening with age. Back and upperwing coverts are blue-gray and average darker on females; they contrast with blackish uppersides of flight feathers. Underwing coverts and underparts are pale blue-gray with fine black vermiculations and some vertical black streaking. Females usually have coarser, darker barring and more vertical black streaking. Primaries show dusky banding on undersides; secondaries show, at most, faint banding. Tail is blue-gray, with three or four incomplete blackish bands. Undertail coverts are white and fluffy.