Plumages, Molts, and Structure

The following description is based on Restall et al. (2006); see also Blake (1977):

Adult male: Head, neck and breast to central belly offwhite, streaked slightly buffy on nape and scalloped on breast. Mantle gray scalloped white; band across upper mantle, scapulars, breast-sides and flanks orange. Wings black with broad white speculum. Large crescent of dark brown behind flanks. Undertail coverts white.

Female: Similarly patterned, but has drab wash to crown and back of neck; orange flanks less extensive; and dark post-flanks patch borders scalloping on sides to belly.

Unmistakable.

Non-breeding adults in the Venezuelan llanos are observed in large flocks during Feb - April in which some birds are missing primary and secondary wing features, suggesting that non-breeders do form molt flocks (Kriese, pers. obs.).

Unlike true geese, Orinoco Goose adults with young in Venezuela do not molt their wing feathers during the brood-rearing period.  It is unclear then if they molt during the non-breeding season (Kriese, pers. obs.).

There is no alternate plumage.

Iris: dark

Bill: Black above, red below.

Tarsi and toes: Bright salmon red in male, and slightly duller orange in the female.  Juveile individuals have duller color on legs and feet compared to adults.

Total length: 61-66 cm (Restall et al. 2006), 61-76 cm (Hilty and Brown 1986).

Linear measurements:

Below from Kriese (2004) and from Davenport, Nole, and Carlos (unpublished data):

Adult male:

tarsus length:  96.6 ± 1.7 mm

body mass:  1800 ± 54.0 g

Adult female:

tarsus length:  86.6± .7 mm

body mass:  1333.8 ± 47.5 g