Black-and-white Owl is a large owl, between 35 and 40 cm in length. As in most owl species, females tend to be larger than males. Black-and-white Owl lacks "ear" tufts and has a rounded head with a prominent dark facial disk outlined with white speckles. The underparts are white with narrow black barring; this pattern extends partially up onto the sides of the neck and the facial disk. The upperparts are black. The tail is black with narrow white barring. Eyes are dark brown, and the bill and feet are orange yellow.
In most of its range, Black-and-white Owl is easy to distinguish from other owls; it is only in the southern portion of its range that it may be confused with its sister species, Black-banded Owl (Ciccaba huhula) of eastern South America. Although superficially similar, these species differ in size, plumage, and distribution. Black-banded Owl is slightly smaller, although this difference may not be very apparent in the field. Its plumage overall is darker; the underparts are dark brownish black with narrow white barring, and it lacks the unbarred blackish crown and back, the hindneck-collar barred whitish and dusky, and the white ventral underparts of Black-and-white Owl. The facial coloration resembles that of Black-and-white Owl, but shows less contrast with the underparts. These two species are not known to overlap, although there are a few records from Colombia of possible hybrids between the two (see Systematics).
The following description is based on Wetmore (1968); see also Ridgway (1914), Stiles and Skutch (1989), and König and Weick (2008):
Adult: Sexes similar. Facial disc black; rim and eyebrows densely speckled whitish. Upperparts generally sooty black, with a prominent collar of narrow white bars across the hindneck (this collar is continuous with the barring of the underparts).Rectrices sooty blackish, with 4 (or more?) narrow white bars, and with a narrow white terminal band. Greater and primary wing coverts faintly mottled with dull grayish brown. Remiges sooty blackish, indistinctly barred with white and grayish brown on the outer webs. Underparts white, densely but narrowly barred with black.
Juvenile: Downy chick whitish. Juvenile overall whitish;above narrowly barred dark brown to blackish-brown, and below creamy-white to buff with dusky barring. Juvenile facial patterns are similar to adult, with dark around the eyes but the white with black barring extends over crown and nape as well as wing coverts. The flight feathers are black, like the adult, and the tail is also the same as the adult.
Undescribed; probably follows the complex basic molt strategy.
Iris: dark orange brown, brown, pale yellowish brown; iris of juvenile dark brown, washed with dusky oily bluish
Bill: bright yellow, orange yellow; cere orange yellow
Tarsi and toes: tarsi feathered, barred dusky and whitish; toes bare and bright yellow or orange yellow; claws yellowish horn
Bare parts color data from Wetmore (1968) and König and Weick (2008).
Total length: 35-40 cm (König and Weick 2008), 38-40.5 cm (Howell and Webb 1995), 41 cm (Hilty and Brown 1986), 43 cm (Hilty 2003)
Linear measurements (specimens, from Wetmore 1968):
male (n = 6)
wing length: mean 261.6 mm (range 254-268 mm)
tail length: mean 152.3 mm (range 144-165 mm)
bill length (culmen from cere): mean 20.0 mm (range 19.0-21.1 mm)
female (n = 9)
wing length: mean 275.2 mm (range 270-279 mm)
tail length: mean 170.2 mm (range 160-178 mm)
bill length (culmen from cere): mean 21.6 mm (range 19.5-22.8 mm)
Linear measurements (live birds, from Gerhardt and Gerhardt 1997):
male (n = 1):
wing length (chord), 286 mm; tail length, 165 mm
female (n = 1):
wing length (chord), 293 mm; tail length, 187 mm
male, 436 g (n = 1; Gerhardt and Gerhardt 1997); female, 535 g (n = 1; Gerhardt and Gerhardt 1997)