Appearance

Potoos (Nyctibius) are large, long tailed birds with cryptic plumage. The head and eyes both are large; the mouth is very wide, although the bill is short. Northern Potoo is a medium sized potoo. The plumage primarily is brown, but heavily barred and mottled with gray, black and white on the upperparts; the underparts are paler, with dark streaking, and a variable amount of black mottling or spotting in the center of the breast. Northern Potoo has yellow (not brown) irides, and often has a black lateral throat stripe.

Northern Potoo is the only species of potoo in most of its range, including on Jamaica and Hispaniola, and in most of Mexico. There is overlap, from extreme southern Mexico south at least to Honduras, with Great Potoo (Nyctibius grandis). Great Potoo is much larger than Northern Potoo, has paler and less mottled (more vermiculated) plumage, has brown irides, and lacks the black lateral throat stripe that Northern Potoo often shows. Northern Potoo is replaced in central Costa Rica by the very similar Common Potoo (Nyctibius griseus); these two species are best distinguished by their very different vocalizations.

The following description is based on Ridgway (1914) and on Cleere (1998); see also Geographic Variation:

Adult: Sexes similar. Crown broadly streaked or striped with black and white, or black with white and pale brownish buff, the black predominating. Nape and back brownish gray to pale buffy brown, finely vermiculated with darker, and narrowly streaked with black. Scapular region similar to back, but the anterior portion irregularly spotted or blotched with black. Lower back and rump dull sooty black or slate blackish, more or less spotted posteriorly with pale buffy brown or brownish gray. Uppertail coverts dusky with small brownish gray or buffy brownish spots. Anterior portion of lesser wing coverts uniform sooty black. Middle coverts and posterior lesser coverts pale cinnamon or buffy cinnamon, sparsely and indistinctly vermiculated with darker grayish and with sharply defined central black streaks. Greater wing coverts mottled or marbled with brownish gray, pale cinnamon, whitish, and dusky. Inner secondaries marbled and mottled with pale and deeper brownish gray and whitish and with sharply defined irregular central black streaks; outer secondaries dusky, mottled or marbled along edges with pale brownish gray and pale cinnamon buff, and with indistinct spots of mottled grayish. Primaries sooty slate blackish, outer webs with large spots of pale gray, inner webs with less distinct and more broken spots of darker grayish. Rectrices banded with brownish black and grayish, the bands very irregular and broken (especially the grayish bands) by irregular lines and marblings, the black bands relatively broader and more uniform on basal portion of tail.

Auricular region mostly plain sooty black or dusky, forming a distinct postocular stripe. Throat pale buffy grayish or cinnamon buff, each feather with a central black streak. Throat usually bordered laterally with a distinct black streak. Breast similar to throat, but more or less vermiculated with grayish and the streaks broader, some of the feathers with a large terminal black spot. Belly and sides like breast but without black spots and the ground color fading to whitish on the flanks and vent. Undertail coverts white to buffy white, sparsely mottled with pale gray and with distinct (but sometimes broken) central black streaks.

Immature: Similar to adult, but paler and whiter (Cleere 1998).

Juvenile: Similar to the immature, but white and spotted blackish brown along the scapulars (Cleere 1998).

Downy chick: Covered in white down at hatching (Cleere 1998).

Little information. Dickey and van Rossem (1938) noted two specimens collected in El Salvador at the end of October were finishing a complete molt; specimens from January and February showed no signs of molt.

Iris: brilliant straw yellow, bright orange yellow

Bill: horn (nearly black)

Toes: whitish, grayish horn

Bare parts color data from Ridgway (1914) and Dickey and van Rossem (1938).

Total length: 36-45 cm (Cleere 1998), 38-43 cm (Howell and Webb 1995), 38-43.5 cm (Ridgway 1914)

Linear measurements (from Ridgway 1914):

jamaicensis, male (n = 4)

wing length: mean 295.2 mm (range 293-297 mm)

tail length: mean 223.7 mm (range 212-235 mm)

bill length (exposed culmen): mean 25.7 mm (range 25-27 mm)

tarsus length: mean 13 mm (range 12-14 mm)

jamaicensis, female (n = 3)

wing length: mean 291 mm (range 285-299 mm)

tail length: mean 212.3 mm (range 210-216 mm)

bill length (exposed culmen): mean 26.3 mm (range 25-28 mm)

tarsus length: mean 13.7 mm (range 13.5-14 mm)

mexicanus, male (n = 1)

wing length: 305 mm

tail length: 220 mm

bill length (exposed culmen): 27 mm

tarsus length: 13 mm

mexicanus, female (n = 1)

wing length: 304 mm

tail length: 216 mm

bill length (exposed culmen): 25.5 mm

tarsus length: 13 mm

Mass:

male, mean 257.3 g (range 210.2-320.5 g, n = 3; Paynter 1955, Klaas 1968, Foster and Johnson 1974)

female, mean 253.1 g (range 246-265 g, n = 4; Paynter 1955, Russell 1964, Klaas 1968)