Appearance

19-29 cm. The Short-tailed Nighthawk is a large nightjar with a short tail. The plumage is cryptically patterned, like other nightjars. Some plumage patterns that are common in nightjars, such as a pale or rufous nape collar, and white markings near the tips of the primaries or on the outer corners of the rectrices, are lacking in this species. The upperparts generally are blackish, spotted cinnamon-rufous; the scapulars and tertials are mottled silvery. White patch on throat. Throat and chest sooty blackish brown, spotted paler. Belly and undertail coverts cinnamon, barred with blackish brown.

Rufous-bellied Nighthawk (Lurocalis rufiventris) of the Andes is the same size and shape as Short-tailed Nighthawk, and has a similar same color pattern. The Rufous-bellied Nighthawk occurs at higher elevations than Short-tailed Nighthawk, however, and is larger, the belly lacks the black barring of Short-tailed, and it has different vocalizations.

The following description, of nominate semitorquatus, is based on Cleere (1998); see also Geographic Variation:

Adult: Sexes similar. Forecrown, crown and nape dark brown, spotted and speckled with rufous and buff. Back, rump and uppertail coverts dark brown, spotted and speckled with rufous and buff. Scapulars grayish white, spotted with brown. Lesser wing coverts dark brown, spotted with grayish white and cinnamon. Greater wing coverts dark brown, barred with deep cinnamon-rufous. Remaining wing coverts dark brown, spotted with cinnamon, rufous, tawny, buff, and grayish white. Primaries brown, boldly ocellated with tawny along outer webs, and barred grayish brown along inner webs. Secondaries brown spotted with pale buff or tawny. Tertials brownish white, mottled with brown. Rectrices brown, barred with tawny or grayish brown, and narrowly tipped with brownish buff or whitish. Lores and auriculars dark brown, spotted with rufous. Chin and sides of throat dark brown, spotted with rufous. Throat white. Breast dark brown, speckled and spotted with grayish white and pale buff; lower breast pale buff, barred with brown. Belly and flanks tawny-buff barred with brown. Undertail coverts tawny-buff, barred brown.

Immature: Similar to adult, but upperparts and wing coverts sprinkled with brownish white feathers, boldly spotted tawny wth blackish brown tips. Scapulars and tertials brownish white, vermiculated with brown and boldly spotted with blackish brown and tawny. Primaries broadly tipped brownish white mottled brown, and the rectrices narrowly tipped with grayish brown mottled brown.

Iris: wood brown (Wetmore 1968), dark brown (Cleere 1968)

Bill: dull black (Wetmore 1968), blackish (Cleere 1968)

Tarsi and toes: brown, scutes outlined in dull white (Wetmore 1968); brownish or grayish flesh (Cleere 1998)

Total length: 19 cm (Ridgely and Greenfield 2001), 20 cm ( Stiles and Skutch 1989), 20-21 cm (Howell and Webb 1995), 21 cm (Hilty 2003)

Linear measurements of noctivagus (from Wetmore 1968):

male (n = 3): wing, mean 181.6 mm (range 177-190 mm); tail, mean 74.0 mm (range 71.1-77.6 m); culmen from base, mean 11.1 mm (range 11.0-11.2 mm); tarsus, mean 12.1 mm (range 11.0-12.8 mm)

female (n = 1): wing 174 mm; tail 73 m; culmen from base 11.9 mm; tarsus 11.0 mm

semitorquatus (from Cleere 1998):

male, wing 163-181 mm, tail 71-75 mm (n = 3); female, wing 175-177 mm, tail 71-80 mm (n = 3)

stonei (from Cleere 1998):

male, wing 188 mm, tail 83 mm (n = 1); female, wing 203 mm, tail 85 mm (n = 1)

schaeferi (from Cleere 1998):

male, wing 175-210, mm tail 75-98 mm (n = a minimum of 5); female, wing 183-198 mm, tail 73-88 mm (n = a minimum of 5)

nattereri (from Cleere 1998):

male, wing 201-208 mm, tail 81-89 mm (n = a minimum of 5); female, wing 196-225 mm, tail 82-103 mm (n = a minimum of 5)

Mass: semitorquatus, 79 g (n = 1, female; Cleere 1998); nattereri, 82-89 g (n = a minimum of 5, males; Cleere 1998)