Red-masked Parakeet is a medium sized, grass green parakeet with a horn colored bill, solid red "mask" covering the forecrown, lores, cheeks and chin, red-feathered lower portions of the inner tibiotarsi "thighs", and red plumage on the leading edge of the wing at the carpal joint "wrist" and lesser underwing coverts, and a moderately long graduated tail. All ages have an unfeathered, bright white (sometimes with light yellow wash) periopthalmic ring. Fledglings are entirely green with no red markings or sometimes with a thin dark red band above the nares; the red plumage pattern gradually begins as flecking, then clumping and finally develops continuous coverage on the head, the bend of wing and lower tibiotarsi, and by 16 months of age the red coloration on the head forms a solid red mask. Red plumage on the head (the mask), wings and legs continues to enlargen and intensify with each successive moult for the remainder of the birds' life. Immature birds' changing red color patterns look similar to those of other red and green Aratinga parakeets (see Similar Species) but the continuous red mask of adults, with a clean edge, is unmistakable. In flight and perched profile, compared with other red and green Aratinga Red-masked Parakeet gives the appearance of having proportionately shorter tail and wings in relation to the body, head and bill size. The common vocalization of Red-masked Parakeet is a repeated nasal, tinny, moderately high pitched eh, eh, eh, eh.
There are 20 species of Aratinga. Red-masked Parakeet is part of a similar-looking "red and green headed" Aratinga group consisting of six other species (Cuban Parakeet, Aratinga euops; Hispaniolan Parakeet, Aratinga chloroptera; Crimson-fronted Parakeet, Aratinga finschi; White-eyed Parakeet Aratinga leucophthalma; Scarlet-fronted Parakeet, Aratinga wagleri; and Mitred Parakeet, Aratinga mitrata). These species share a similar green body plumage with red head markings and a horn or light colored bill. Red-masked Parakeet usually does not overlap geographically with these species in the wild (with the rare exception of Scarlet-fronted parakeet in Peru), but often can be found together with any number of these species in naturalized populations in several locations worldwide. In these naturalized populations, mixed species flocks and hybrids occur, causing potential problems in parakeet identification.
Fledglings of all six of these species have nearly no red plumage coloration and gradually acquire it as they age. Young Red-masked Parakeets, up to about six to eight months past fledgling, could be mistaken for White-eyed Parakeet, as the red head plumage initially appears as flecking; at about eight to eleven months they can be mistaken for Mitred Parakeet, as the flecking merges into blotches; and at about one year old the red flecking and blotches coalesce into a continuous coverage concentrated on the forecrown and opthalmic areas making them look, at distance, vaguely similar to Scarlet-fronted Parakeet and to Crimson-fronted Parakeet. It is important to be mindful of the potential age of the individual during the identification process.
In its native range, in northwestern Peru and southwestern Ecuador, Red-masked Parakeet would be most likely confused with Scarlet-fronted Parakeet (Aratinga wagleri frontata), although Scarlet-fronted has a more montane distribution. Scarlet-fronted Parakeet is a slightly larger than Red-masked, has mostly green underwing coverts, and the red on the head is confined to the forecrown.
The Red-masked Parakeet, Aratinga erythrogenys (Lesson) 1844, is a 33 cm long, long-tailed parrot. In Hawai`i its overall morphology match literary description (see Juniper and Parr 1998).
Adult: Sexes similar, bright grass green with a solid bright-red head mask that completely encloses the bare periopthalmic ring and eye, red-feathered lower portions of the inner tibiotarsi "thighs," on the leading edge of the wing at the carpal joint "wrist" and lesser underwing coverts. The red mask generally has a defined boarder and covers the forecrown, lores, cheeks and chin. The mask (and to a lesser degree, other red plumage) expands with each successive moult over many individuals' lives. Old individuals may have a red head mask that nearly covers the entire head, extending back to the nape and neck. Bare periopthalmic ring bright white with variable lemon-yellow wash and thin black boarder next to eyeball. Eye with two-toned iris: inner iris ring dark grey, outer iris ring orange. This data comes, in part, from wild Red-masked parakeets observed in-hand during a capture, banding and radio-telemetry field study by the author in Hawai`i.
Immature: Fledgling birds a duller grass green with no red plumage except for a thin dark red/maroon strip surrounding the nares. White periopthalmic ring less bright and reduced in width. At about three months post fledge flecks of red appear on forecrown and cheeks, at eleven months an incomplete red mask is formed with complete red coverage on the forecrown and red blotching on the lores and cheeks (see image gallery). At this age the mask never completely surrounds the eye; also, red plumage on inner thighs and underwing coverts becomes noticeable. By sixteen months old most individuals have a solid red mask that completely encircles the eye and other red plumaged areas are prominant. It is assumed that red mask plumage expands primarily during each moult however red head plumage, especially in very young individuals, seems to progress more fluidly.
In Honolulu Hawai`i an adult was observed to be growing two central retricies and had pin feathers present on its nape on 10 December 2011. A mist-netted adult female showed heavy moult on retricies, head, neck, and rump on 19 February 2006. An adult male was moulting leg, head and neck feathers; a female was moulting vent, breast, head, cheek, upper wing coverts, secondary feathers; a female was moulting upper wing coverts and legs and another female was moulting leg feathers on 26 February 2006. An adult male was moulting head, cheek, and undwing coverts on 11 March 2006. A yearling nonbreeding male was bilaterally missing one secondary feather on 12 August 2006. Adult Red-masked parakeets mist netted in the months of April and August did not show signs of moulting. Molt status during months not listed here was unknown. Sexes were determined by DNA sample PCR assay.
Iris: Outer iris orange, inner iris gray or gray-brown; iris completely gray in immatures
Periopthalmic skin: Bright white with a variable lemon yellow wash.
Bill: Pale horn, dull horn
Tarsi and toes: light gray with slight dull pink mottling, nails dark.
Bare parts color data from Juniper and Parr (1998) and personal observations, in-hand, of wild individuals in Hawaii.
Measurements from three A. erythrogenys in the collection of the United States Smithsonian National Museum of Natural History (Smithsonian) (measured by Kalodimos; from Ecuador, Peru, and 1 with unknown provenance)
Measurements from nine A. erythrogenys in the O`ahu, Hawai`i population.
Mass: 151 g (n = 1, male, captive; Dunning 2008).