Red-Eared Parakeet: Buitrón-Jurado, Galo, and Virginia Sanz. “Notes on the Diet of the Endemic Red-Eared Parakeet Pyrrhura Hoematotis and Other Venezuelan Montane Parrots.” BioOne, Spanish Society of Ornithology/BirdLife, Sept. 2016
Amazon Parrots (Blue-fronted and Yellow-headed): Martens, Johanne, et al. “Diet and Feeding Behaviour of Naturalised Amazon Parrots in a European City.” BioOne, Netherlands Ornithologists' Union, 2013
Scarlet Macaw: Vaughan, Christopher, et al. “Scarlet Macaw, Ara Macao, (Psittaciformes: Psittacidae) Diet in Central Pacific Costa Rica.” Academia.edu, 2006
Scarlet Macaw: Renton, Katherine. “Diet of Adult and Nestling Scarlet Macaws in Southwest Belize, Central America.” Biotropica, vol. 38, no. 2, Mar. 2006, pp. 280–283
Red-Eared Parakeet: Buitrón-Jurado, Galo, and Virginia Sanz. “Notes on the Diet of the Endemic Red-Eared Parakeet Pyrrhura Hoematotis and Other Venezuelan Montane Parrots.” BioOne, Spanish Society of Ornithology/BirdLife, Sept. 2016 Amazon Parrots (Blue-fronted and Yellow-headed): Martens, Johanne, et al. “Diet and Feeding Behaviour of Naturalised Amazon Parrots in a European City.” BioOne, Netherlands Ornithologists' Union, 2013 Scarlet Macaw: Vaughan, Christopher, et al. “Scarlet Macaw, Ara Macao, (Psittaciformes: Psittacidae) Diet in Central Pacific Costa Rica.” Academia.edu, 2006 Scarlet Macaw: Renton, Katherine. “Diet of Adult and Nestling Scarlet Macaws in Southwest Belize, Central America.” Biotropica, vol. 38, no. 2, Mar. 2006, pp. 280–283