The grey-winged trumpeter (Psophia crepitans) is a member of a small family of birds, the Psophiidae. It is found in the northern Amazon rainforest and Guiana Shield in tropical South America. Unlike all other trumpeters, the rump and back are grey in the grey-winged trumpeter.
It has two subspecies separated by the Rio Negro: The nominate from the Guiana Shield, and napensis from the north-western Amazon. Although their plumage differences are relatively minor, some have suggested they should be treated as separate species (instead of subspecies) due to genetic differences. Genetic evidence also suggests ochroptera, traditionally considered a subspecies of the pale-winged trumpeter, actually is closer to the grey-winged trumpeter. source