The Scarlet Macaw (Linnaeus, 1758 -Psittacus macao) has been recognized as a monotypic species (Forshaw 1989). During the last two decades, however, aviculturists have expressed that Scarlet Macaws from Central America and Mexico and South America have some differences in wing plumage color and body size (Smith 1991). Abramson and Thomsen (1995) suggested that there are probably three subspecies of Scarlet Macaws. Their argument, nevertheless, is based on captive bred specimens and they did not provide information on their natural distribution, morphometrics or genetics. Voren (1996) mentioned also that among aviculturists it is common to refer to the Bolivian Scarlet Macaws as the "giant Bolivians." Nevertheless, he suggested that Scarlet Macaws captured in Colombia are smuggled in large quantities into Bolivia for exporters. The traffic of Scarlet Macaws between countries in Latin America to supply bird dealers and the captive breeding of these different geographical populations make it unacceptable to describe subspecies solely from captive macaws or from doubtful origin. Captive breeding of Scarlet Macaws in the United States and other countries has been a very common practice for many decades (Hopkinson 1926; Schubot et al. 1992; Abramson 1991, 1996). The captive breeding of Scarlet Macaws from South America with specimens from México or Central America and the encouragement of color mutations (e.g., plumage predominantly white with normal iris, bill, and feet colors) of this species have been common within aviculturists (De Dios and Sweeney 1995, Gabel and Elgas 1995, Voren 1996). Recently, several avicultural organizations (e.g., American Federation of Aviculture) have issued policies to stop hybridizing macaws and other birds (Gabel and Elgas 1995). Aviculturists, particularly in the United States and Philippines, who continue to hybridize macaws and other parrots apparently are driven by curiosity and financial incentives (De Dios and Sweeney 1995). These macaw hybrid offspring usurp the biological value of their parents by diverting genetic material from their respective species.
Wiedenfeld (1994) suggested regarding the morphometrics and color plumage of Scarlet Macaws from known localities suggested that the species should be split in two subspecies, A. macao cyanoptera and A. m. macao. The first possible subspecies historically occurred from México, through Belize, Guatemala, El Salvador, Honduras, to central Nicaragua. The second possible subspecies range from Panama to South America and should be refered as the nominate race (A. m. macao). Specimens occurring in southern Nicaragua and northern Costa Rica should be considered a population in a zone of intergradation between the two races. Further phylogenetic studies on the degree of the genetic divergence and habitat differences on proposed subspecies are needed.