The Lilac-crowned Parrot is a medium-sized Amazon parrot with predominantly green plumage. The species is characterized by a red fore-head, green cheeks, and mauve or lilac hind-crown and neck (Forshaw 1989). Primary and secondary wing feathers are tipped violet blue, with a red speculum at the base of the first five secondary wing-feathers (Forshaw 1989). This displays a red and blue band on the upper wing when the parrots are in flight.
The species most similar to the Lilac-crowned Parrot within its range is the White-fronted Parrot Amazona albifrons. However, the White-fronted Parrot may be distinguished by red lores and eye-ring and a white forehead, as well as being slightly smaller than the Lilac-crowned Parrot (Howell and Webb 1995). The Yellow-headed Parrot Amazona oratrix also occurs within the range of the Lilac-crowned Parrot on the Pacific coast. However, the Yellow-headed Parrot is much larger, with a distinctive yellow head (Howell and Webb 1995).
The closely related Red-crowned Parrot Amazona viridigenalis is very similar in appearance to the Lilac-crowned Parrot. However, the Red-crowned Parrot is endemic to north-eastern Mexico on the Atlantic slope from Nuevo Leon to northern Veracruz, and is distinguished by a red crown and lores (Forshaw 1989, Howell and Webb 1995).
Detailed description of adult birds comes from Forshaw (1989).
Plumage is an overall green color with yellowish-green underparts. Feathers are edged with black to give a scalloped appearance on the body. The forehead is a deep maroon-red. The crown, hind-neck and nape are a pale bluish-lilac color. The cheeks and ear coverts are a brighter yellowish-green with no black edges to the feathers. Primary feathers are violet-blue, while the secondary feathers are green but tipped with violet-blue. The first five secondary feathers have a red speculum near the outer edge which can be seen on the upper-edge when the wings are open in flight. The wing coverts and underside of flight feathers are green. The tail is green, tipped with a lighter yellowish-green. The bill is horn colored, while the orbital ring and legs are pale grey. Adult birds have an amber colored iris.
The pattern of nestling development was described by Renton (2002).
Lilac-crowned Parrot nestlings hatch with eye-lids fused together, and a light covering of feather down, and weigh 11–19 g on hatching (Renton 2002). Eye-lids begin to separate two weeks after hatching, with eyes fully open after three weeks.
Nestlings rapidly increase in body mass during the first four weeks after hatching, reaching 90% of body mass in the first month (Renton 2002). Feather development occurs during the second month after hatching, with primary wing feathers erupting first at about 26 days of age (Renton 2002).
This is closely followed by development of the secondary feathers, wing coverts, and tail feathers. The head feathers begin to develop five weeks after hatching, with the yellow-green cheek feathers being the first to unsheathe, followed by the bluish feathers of the crown and hind-neck. The red feathers of the forehead are last to develop at about six weeks after hatching. Body feathers begin to develop at five weeks after hatching, and the red speculum band on the secondary feathers begins to emerge 7-8 weeks after hatching, just prior to fledging.
Juveniles are similar to adults, but are distinguished by a dark brown eye color compared to the amber iris in adult birds (Forshaw 1989, Howell and Webb 1995). Juveniles also have fewer red feathers on the forehead. Eye color and the red forehead take on adult appearance after the first year.
Lilac-crowned Parrots have a bare orbital ring, with no feathers on the feet, though the legs are feathered.
Body length: 30.5-34.5 cm (Howell and Webb 1995)
Body mass: 280-327 g (Renton 2002)
Wing length: males: 191-215 mm; females: 185-208 mm (Forshaw 1989).