Internet Bird Collection Parrots: A Guide to Parrots of the World, Juniper and Parr, 1998 ML Media Collection Catalogue 68611, Black-headed Parrot (Pionites melanocephala), Schwartz, Paul, Rio Grande, Venezuela, Jul. 4 1966, Cornell Lab of Ornithology. Site Parrots of the World, Forshaw and Cooper, 1989. 2010 issue Parrots of the World, Forshaw, 2006.
The green-thighed parrot (Pionites leucogaster leucogaster) is a subspecies of White-bellied caique belong into the family Psittacidae The species Pionites leucogaster (also known as the white-bellied parrot or white-bellied caique in the aviculture business) contains three subspecies including the nominate race, but recent morphological work suggests the species should be split into three.