dark morph Rough-legged Hawk

during a cracking spell of birding at Port Rowan on our first day this dark morph 2cy Rough-legged Hawk was hunting on the east side of the pond; I was very interested to see a bird in this plumage only having seen pale morph birds previously in California; the dark barred uppertail appeared at odds with our conception of Rough-legs but is typical of birds of this age; the tail pattern ages the bird; the smaller lower photo produces the best overall impression of the bird in sunlight; in good light the rufous underwing coverts can be seen to contrast with the blacker carpal patches but in shade the whole of the underwing coverts and carpal appeared concolorous and dark; it spent long spells hovering which is always a bit of a pointer to this species.