Plumage very full, soft, and downy; the feathers generally oblong. Those on the face linear, stiffish, with loose barbs, and disposed in two large disks surrounding the eyes; besides which there is a ruff of softer linear, denser feathers from the forehead, behind the ears, to the chin. The conch of the ear is very large, although greatly exceeded by that of many other Owls, and furnished with an anterior semicircular operculum, beset with slender feathers. Wings very large, concave; primaries, decurved toward the end, the first with the tips of the filaments separated, and recurved in its whole length, the second in its terminal half; the first quill short, being of the same length as the sixth, the second 2-1/2 inches longer, the third 1-1/2 inch longer than the second, 1/4 inch shorter than the fourth, which is the longest, or equals the next. The first five have their outer webs more or less cut out towards the end, and the first seven have their inner webs sinuate. The tail is long, ample, rounded, of twelve broad rounded feathers. Bill yellow. Iris bright yellow. Claws brownish-black. The general colour of the upper parts is greyish-brown, variegated with greyish-white in irregular undulated markings; the feathers on the upper part of the head with two transverse white spots on each web; the smaller wing-coverts of a darker brown, and less mottled than the back; the outer scapulars with more white on their outer webs; the primary quills blackish-brown toward the end, marked in the rest of their extent with few broad light-grey oblique bands, which are dotted and undulated with darker. Tail-feathers similarly barred, darker towards the end, the middle ones more intricately marked. The feathers of the ruff are white towards the end, dark-brown in the centre. The disks are on their inner side grey, with black tips; in the rest of their extent greyish-white, with six bars of blackish-brown very regularly disposed in a concentric manner; feathers on the chin or upper part of throat greyish-white. All the under parts are greyish-brown, variegated with greyish and yellowish white; the feet barred with the same. Length to end of tail 30-1/2 inches, to end of wings 27-1/4, to end of claws 22; extent of wings 48-1/2; wing from flexure 19-1/4; tail 12-3/4; bill along the ridge 1, along the edge of lower mandible 1-3/4; breadth of gape 1-1/2; tarsus 2-1/2; hind toe 7/12, its claw 7/8; middle toe 1, its claw 1-5/12. BLACK-SHOULDERED HAWK. _FALCO DISPAR_, TEMM. PLATE CCCLII. MALE AND FEMALE.