Number observed: 1
Comments: Sub adult. Large buzzard-like eagle soaring on slight dihedral with longish, rounded tail. All dark above and below, but with a single oval white patch on upper side of the wing at the base of the inner primaries. Relatively small head, broad rounded tail and and localized white patch on wing ruled out Bald Eagle. We waited for it to come in to DC airspace, but it never did.