John James Audubon,
Ornithological biography, Vol. 4…
(1835)
“ Bill black; the cere and soft basal margins yellow. Iris bright red. Tarsi and toes yellow, of a darker tint than the cere; claws black. All the lower parts are pure white, with the exception of a patch on five or six of the larger wing-coverts; the forehead is also white, as are the cheeks; the superciliary bristles black, the white of 370 the head gradually blends into the general colour of the upper parts, which is ash-grey; the smaller wing-coverts bluish-black; the shafts of the quills brownish-black; all the feathers of the tail, excepting the two middle, white ”
