Appearance

Rufous-winged Ground-Cuckoo is a large, terrestrial cuckoo (about 50 cm in length) that resembles Greater Roadrunner (Geococcyx californianus) of the American Southwest and Mexico in shape and behavior. As such, it has a large, sharply-ridged bill, prominent crest, long tail, and strong feet and toes. Rufous-winged Ground-Cuckoo is deep purplish blue on crest, head, neck, and upper breast; its throat, lower breast, and belly are ashy brown. Black borders on the feathers of the lower throat form prominent “V” pattern. The wings are dark brownish red with bluish black primaries. The back of Rufous-winged Ground Cuckoo is olive, glossed with purple; the central rectrices are metallic purple, and the remaining rectrices are greenish black. The Bare orbital skin red; the bill is black with a paler tip.

The Neotropics are home to five species of Neomorphus ground-cuckoos; however, they generally replace one another geographically so that only one species inhabits any given forest region. Also the five species differ in the color and patterning of their anterior underparts and upperparts, and in the color of their bill and bare orbital skin (Haffer 1977).

Haffer (1977) suggested that a potential contact zone between Rufous-winged Ground-Cuckoo and Red-billed Ground-Cuckoo (N. pucheranii) could exist in the upper Rio Negro area, although there are no specimens to support this. In any event, Red-billed Ground-Cuckoo easily can be differentiated from Rufous-winged by its bright red bill, paler throat, narrow blackish breast band, and pale belly. There is unlikely to be contact zones between Rufous-winged Ground-Cuckoo and any other species of Neomorphus.

Adult: Sexes similar. Head, crest, neck, and upper back deep purplish blue; back and wing coverts glossy purplish olive; primaries bluish black, secondaries dark brownish red. Lower back and upper tail coverts olive. Tail blackish, central rectrices metallic purple, outer rectrices black glossed with green. Throat ashy gray to dark gray; lower throat feathers gray with V-shaped black borders giving scaled appearance. Breast black; lower breast and belly dull ashy brown to slate gray. Undertail coverts slate gray.

Juvenile: Crown black, back and wing coverts brownish slate. Primaries black, secondaries dark brownish red. Lower back and rump black. Tail black, rectrices glossed with purple and green, rectrices narrower than in adult. Underparts slate.

Nestling: Just-fledged young had black skin below, and dark brown hair-like feathers attached to tips of crown feathers.

Descriptions from Payne (2005) and Erritzöe et al. (2012).

Rufous-winged Ground-Cuckoo presumably follows the Complex Basic molt strategy; otherwise, molt unknown.

Iris: brown in adult and juvenile.

Facial skin: bare orbital skin red to reddish-violet; skin on nape cobalt blue covered by black feathers. Bare orbital skin dull red in juvenile; skin on nape cerulean blue covered by black feathers.

Bill: black with greenish to greenish white tip on maxilla. Nostrils in Neomorphus are broadly operculate and opening is slit-like, unlike other cuckoo genera. Bill black in juvenile and less deep than adult.

Tarsi and toes: greenish gray to gray blue in adult.

Bare parts descriptions from Payne (2005) and Erritzöe (2012).

Total length: 48-56 cm (Gray 1849, Meyer de Schauensee and Phelps 1978, Hilty 2003).

Linear measurements (from Payne 2005):

male (n = 6)

wing length (flat): mean 169.5 mm (range 164-176 mm)

tail length: mean 275.7 mm (range 262-290 mm)

bill length: mean 40.7 mm (range 39-42 mm)

tarsus length: mean 67.4 mm (range 63-71 mm)

female (n = 6)

wing length (flat): mean 164.3 mm (range 152-174 mm)

tail length: mean 288.5 mm (range 266-300 mm)

bill length: mean 41.3 mm (range 38-44 mm)

tarsus length: mean 69.8 mm (range 68-71 mm)

Mass (from Payne 2005):

male, mean 435 gm (range 350-520 gm; n = 2)

female, mean 327.5 gm (range 315-340 gm; n = 2)

Female fledged young (emaciated) 144 gm

Wing formula: P4 = 3 = 2 > 5 = 1 > 6 > 7 > 8 > 9 > 10.