Fossil (or subfossil) black vultures cannot necessarily be attributed to the Pleistocene or the recent species without further information: the same size variation found in the living bird was also present in its larger prehistoric relative.

[3] Humans may have interacted with this species: a subfossil bone of the C. occidentalis was found in a Paleo Indian to Early Archaic (9000–8000 years BCE) midden at Five Mile Rapids near The Dalles, Oregon.

[7] The southern birds were of the same size as present-day northern black vultures and can only be distinguished by their somewhat stouter tarsometatarsus and the flatter and wider bills, and even then only with any certainty if the location where the fossils were found is known.

[8] C. occidentalis was a high-altitude specialist, being primarily found throughout the Andes of South America north to the arid montane regions of the western United States.

It is thought that these lowland areas may have provided feeding opportunities, including trapped megafauna in the La Brea Tar Pits, mass accumulations of dead salmon in Oregon, and washed-up carcasses on the Florida coastal plain.