Appearance

Tinamous are pudgy, terrestrial birds with very short tails and rounded wings. Nothuras are small, short billed, tawny tinamous, all of which inhabit grasslands or open scrub. Spotted Nothura is somewhat variable, but usually has pale, grayish or olive upperparts, spotted and vermiculated with black. The underparts are buffy, the neck and breast more or less streaked with dusky. The sexes are similar.

Spotted Nothura is the most widespread species of nothura and overlaps with all other members of the genus. White-bellied Nothura (Nothura boraquira) has bright yellow tarsi and toes, has paler (whiter) underparts, has finer spotting on the sides of the breast and finer barring on the flanks, and the inner webs of the remiges are entirely dark. Lesser Nothura (Nothura minor) is smaller and more rufescent, and is restricted to campo grassland, avoiding areas with shorter grass or agricultural fields. Spotted Nothura is very similar to Darwin’s Nothura (Nothura darwinii), but Spotted Nothura has longer tarsi and toes (e.g., middle toe with claw typically 24-28 mm in Darwin's but over 28 in most subspecies of Spotted; Conover 1950), and the inner webs of the outermost primaries of Darwin's are unmarked (rather than barred as in Spotted). Spotted Nothura also is similar to Chaco Nothura (Nothura chacoensis), but Chaco has paler upperparts (ochraceous buff rather than dusky rufescent or grayish black), the dark markings of the neck and breast are duller, narrower, and less prominent, and the breast and belly are much paler and brighter. Dwarf Tinamou (Taoniscus nanus) is very much smaller and pudgier. Red-winged Tinamou (Rhynchotus rufescens) is much larger and is more ochraceous. Crested tinamous (genus Eudromia) are much larger and have a long, thin crest. Nothoprocta tinamous are larger, with a longer, more decurved bill, and often have a more noticeable crest.

The following description is based on Blake (1977); see also Geographic Variation:

Adult: Sexes similar. Crown entirely dark, or streaked with pale buffy gray. The sides of the head, and the nape and hindneck, pale ochraceous or grayish buff, patterned with narrow to broad black stripes. The base coloration of the upperparts is pale grayish or olivaceous brown, spotted and vermiculated with black, and throughout narrowly striped with yellowish white. Wing coverts ochraceous or tawny, barred with black. Remiges dull brown or blackish, evenly barred on both webs with buff or reddish ochre. Throat white, immaculate. Lower foreneck and underparts tawny buff or ochraceous; the belly is unmarked, but the rest of the underparts are makred with brown or blackish stripes, spots, and, on the flanks, bars.

Immature: Very similar to the adult, but upperparts less boldly marked; throat less pure white; and breast spotted, rather than striped.

Little information.

Iris: dusky yellow (adult male, and up to 37% of females) or orange brown (62% of adult females)

The irides are dark brown in both sexes at hatching.

Bill: maxilla brown, mandible yellow

Tarsi and toes: dull yellowish

Bare parts color data from Bump and Bump (1969) and Blake (1977).

Total length: 23 cm (Fjeldså and Krabbe 1990), 24-26.5 cm (Blake 1977)

Linear measurements (from Blake 1977):

cearensis, male (n = 1; type)

wing length (flat): 114 mm

bill length (exposed culmen): 18 mm

tarsus length: 29 mm

major, male (n = 4)

wing length (flat): mean 129 mm (range 126-132 mm)

bill length (exposed culmen): mean 19 mm (range 18-20 mm)

major, female (n = 3)

wing length (flat): mean 132.3 mm (range 121-140 mm)

bill length (exposed culmen): mean 18.6 mm (range 18-19 mm)

paludivaga, male (n = 4)

wing length (flat): mean 131 mm (range 127-136 mm)

bill length (exposed culmen): mean 19 mm (range 17-21 mm)

tarsus: 33 mm (n = 1)

paludivaga, female (n = 8)

wing length (flat): mean 130.5 mm (range 125-134 mm)

bill length (exposed culmen): mean 18.8 mm (range 18-21 mm)

maculosa, male (n = 10)

wing length (flat): mean 132.7 mm (range 128-141 mm)

bill length (exposed culmen): mean 17.6 mm (range 17-19 mm)

maculosa, female (n = 10)

wing length (flat): mean 134.4 mm (range 132-138 mm)

bill length (exposed culmen): mean 18.7 mm (range 17-20 mm)

pallida, male (n = 4)

wing length (flat): range 131-139 mm

tarsus length: mean 37.7 mm (range 36-39 mm)

pallida, female (n = 1)

wing length (flat): 128 mm

annectens, male (n = 5)

wing length (flat): mean 135.4 mm (range 130-143 mm)

bill length (exposed culmen): mean 16.7 mm (range 16-17 mm)

annectens, female (n = 7)

wing length (flat): mean 139.7 mm (range 132-145 mm)

bill length: mean 17.3 mm (range 16-18 mm)

submontana, male (n = 1; type)

wing length (flat): 153 mm

bill length (exposed culmen): 19 mm

tarsus length: 41 mm

nigroguttata, male (n = 5)

wing length (flat): mean 140.6 mm (range 138-144 mm)

bill length (exposed culmen): mean 17.6 mm (range 16-19 mm)

nigroguttata, female (n =5)

wing length (flat): mean 144 mm (range 135-155 mm)

bill length (exposed culmen): mean 18 mm (range 16-19 mm)

Mass: 

annectens, male (n = 29): mean 252.9 g ± 21.3 g (range 214-294 g; Bump and Bump 1969: 146-148)

annectens, female (n = 18): mean 272 g ± 33.3 g (range 173-323 g; Bump and Bump 1969: 146-148)