Editor’s Note (August 2016): Maps, rich media, and text have been updated to reflect a taxonomic change/split for this species. This species account is still being edited and may contain content from an earlier version of the account.
The White-winged and Yellow-chevroned parakeets, natives of South America, were formerly considered subspecies of the Canary-winged Parakeet (see Systematics, below). Their popularity as pets led to their importation and the subsequent establishment of feral populations in California and Florida. More than 230,000 White-winged Parakeets were imported from 1968 to 1972, and large numbers of these birds apparently escaped, leading to the rapid appearance of this species in the metropolitan areas of Miami, Los Angeles, and San Francisco. In the early 1970s the Miami population of White-wings was estimated at 2,000, and the birds occurred on both coasts of Florida.
After 1972, the importation of White-wings dropped to near zero, and starting in 1977, large numbers of Yellow-chevroned Parakeets were imported to fill the demand (more than 74,000 were imported from 1977 to 1990). With these imports came escapes, and the Yellow-chevroned Parakeet also began to appear in the wild.
Population dynamics of the 2 species are difficult to interpret because of the irregular coverage of exotics on Christmas Bird Counts and the tendency of U.S. observers to report both species as “Canary-winged Para-keet.” But the White-winged Parakeet appears to have declined slowly since the early 1970s and contracted its range as imports stopped providing a source of fresh escapees. Today only a few individuals occur in California, and a few hundred remain in Miami. Trends in numbers of the Yellow-chevroned Parakeet are less clear, but this species is more common in California than the White-winged, and a few hundred occur in Florida.
In the United States, these species feed on a variety of fruits, seeds, buds, and flowers, relying heavily on exotic plantings of figs and other tropical species. Both species excavate nest cavities in palm trees in the U.S. In other areas they are known to nest in tree cavities and even the arboreal nests of termites (Isoptera).
These species are highly social; both feed, roost, and travel in groups, and pairs remain together almost continuously. Roosting assemblages of White-winged Parakeets in Miami have contained as many as 700+ individuals, and in South America groups of more than a thousand have been reported. Despite their sociality, these parakeets are extremely aggressive. Studies of White-wings have documented a well-developed array of threat displays, and suggest that even duetting by pairs is a way to improve success in agonistic interactions.
Neither species has been well studied in its native range; most information comes from travelers' anecdotal observations. In the United States, the White-winged and Yellow-chevroned parakeets have been the subject of few scientific investigations. Our knowledge of the White-winged is based mostly on studies of the behavior, reproduction, development, and status of the Miami population ( Schroads 1974 ); observations of a small flock in San Francisco ( Arrowood 1981 ); and observations of captive individ-uals (Arrowood Arrowood 1986 , Arrowood 1988 , Harris 1985a ). To date, the only study that has focused exclusively on the Yellow-chevroned Parakeet is the description of the first breeding of this species in captivity ( Vane 1971 ). All other information on these 2 species comes from general reviews of exotic species ( Garrett 1997a , Garrett et al. 1997 ), anecdotal accounts, personal observations, and data gathered for this account.
Although long treated as 2 separate species in South America, Yellow-chevroned and White-winged parakeets were recognized as specifically distinct by North American ornithologists only in 1997. Even though these species are native to South America, this split is relevant to North American ornithologists because both species occur sympatrically in Florida and California.
New data show that the White-winged and Yellow-chevroned parakeets mate assortatively, providing the strongest evidence to date in support of the split. A general lack of scientific investigation and the former subspecific status of the Yellow-chevroned Parakeet have conspired to obscure our understanding of the biology and status in these species in the United States.