Appearance

Amazon parrots (Amazona) are medium to large parrots with relatively short, blunt-tipped tails. Yellow-headed Parrot is a large, primarily green amazon; the sexes are similar. The upperparts, wing coverts, and underparts are green, with paler uppertail coverts. In the nominate subspecies, the head, nape, and chin are bright yellow with some scattered green feathers on the sides of neck. The leading edge of wing and carpal area have variable amounts of red and yellow. The primaries and secondaries are green at the base, becoming blue-black towards tips; the bases of the outer secondaries red; and the underwing is green. There is significant geographic variation in the amount and distribution of yellow and red plumage in this species (see Geographic Variation). The thighs have a variable mix of green and yellow feathers. The tail is green with yellowish green tips. and red at the base on the inner webs of the lateral feathers. The iris is amber, the bill and cere are pale, and the tarsi and toes are gray.

Red-lored Parrot (Amazona a. autumnalis) is slightly smaller than Yellow-headed Parrot. It has red lores and forehead, and a bluish crown; it lacks red on the bend of the wing, and the yellow on head is limited to the anterior auriculars. However, some subspecies and immatures of Yellow-headed Parrots have less yellow on the head. The bill of Red-lored Parrot bill is a somewhat darker horn. These two species also can be distinguished by voice.

Mealy Parrot (Amazona farinosa) is slightly larger than Yellow-headed. Mealy lacks yellow on the head and has a pale blue crown, a broader whitish orbital ring, and a reddish eye; it also lacks the red on the bend of the wing (Howell and Webb 1995).

The caribaea subspecies of Yellow-naped Parrot (Amazona auropalliata) has a darker bill and cere/bristle coloration, the yellow on nape and head is less extensive, and the yellow crown patch is narrower than the rounded or triangular patch in the hondurensis subspecies of Yellow-headed Parrot (Lousada and Howell 1997, Juniper and Parr 1998).

The following description refers to nominate oratrix; see also Geographic Variation:

Adult: Yellow-headed Parrot is a large, primarily green amazon; the sexes are similar. Upperparts are grass green with darker green tips on some feathers. Uppertail coverts are paler; wing coverts green, sometimes with paler yellowish margins to some feathers. Head, nape, and chin bright yellow with some scattered green feathers on sides of neck in some birds. Leading edge of wing and carpal area with variable red and/or yellow markings. Primaries and secondaries green at base (more emerald than coverts) and blue or blackish to bluish violet toward tips; base of outer five secondaries bright red forming speculum; underwing is green. Throat green with variable blue suffusion and dark margins to feathers in some birds; breast and belly green with yellowish or bluish suffusions in some. Thighs have yellow feathers in some birds. Tail green with yellowish green tips and red at base on inner webs of lateral feathers (Juniper and Parr 1998).

Juvenile: Yellow is restricted to the crown and lores; the red or yellow at bend of wing or on rectrices reduced or absent; and the tibial feathers are green.

Immature: Largely green, yellow restricted to crown, lores, anterior auriculars, and throat; Areas of yellow and red plumage increase with first molt during 12-16 months after fledging and continue to increase with each successive molt. Immatures attain adult plumage in 2-4 years (Howell and Webb 1995), or adult plumage is attained at sexual maturity at 3-5 years (Lousada and Howell 1996).

No information reported.

Iris: orange or amber; pale or whitish orbital ring with dark eyelid edge. Fledglings have duller, browner eyes; eye color changes rapidly from grey-brown to pale amber in first six months of age, then changes gradually to amber over first 2-3 years (Lousada and Howell 1996).

Bill: bill of adult bill pale to very pale or grayish-horn; cere and bristles pale to pale horn-flesh. Bill of fledgling and juvenile duskier; cere and bristles darker, or gray.

Tarsi and toes: Legs and feet gray; claws dark on one-year old and four-year-old individuals, and pale on three-year old individual.

Bare parts information from Howell and Webb (1995), Lousada and Howell 1996), Juniper and Parr (1998), and Eisermann (2003).

Total length: 35 cn (Juniper and Parr 1998), 35.5-38 cm (Howell and Webb 1995)

Linear measurments:

wing length, range 206-244 mm; tail length, range 104-135 mm; bill length, range 30-37 mm; tarsus length, range 23-28mm (Juniper and Parr 1998).

oratrix: 15 males; wing length, mean 232.7 mm (range 222-244 mm); tail  length, mean 118.2 mm (range 104-135 mm); bill length (exposed culmen), mean 33.9 mm (range 30-37 mm); tarsus length, mean 26.9 mm (range 25-28 mm).

13 females; wing length, mean 222.4 mm (range 206-233 mm); tail length, mean 114.2 mm (range 105-126 mm); bill length (exposed culmen), mean 31.7 mm (range 30-36 mm); tarsus length, mean 25.5 mm (range 23-27 mm) (Forshaw 1977).

tresmariae: 10 males; wing length, mean 241.2 mm (range 26-245 mm); tail length, mean 129.2 mm (range 118-136 mm); bill length (exposed culmen), mean 34.3 mm (range 32-35 mm); tarsus length, mean 27.2 mm (range 26-28 mm).

4 females; wing length, mean 230.5 (range 229-232 mm); tail length, mean 124.3 mm (range 116-130 mm); bill length (exposed culmen), mean 32.5 mm (range 31-33 mm); tarsus length, mean 25.5 mm (range 25-26 mm) (Forshaw 1977).

belizensis: 3 males; wing length, mean 218.7 mm (range 216-222 mm); tail length, mean 117.7 mm (range 113-120 mm); bill length (exposed culmen), mean 35.0 mm (range 34-36 mm); tarsus length, mean 25.7 mm (range 25-27 mm).

3 females; wing length, mean 209.7 mm (range 205-217 mm); tail length, mean 103.7 mm (range 97-109 mm); bill length (exposed culmen), mean 32.3 mm (range 32-33 mm); tarsus length, mean 26.0 mm (range 25-27 mm) (Forshaw 1977).

hondurensis: wing length (chord) 212 mm; tail length, 100 mm; bill length (culmen from nostril) 30 mm; length of middle toe without nail 30 mm (n = 1, holotype, female; Museum of Comparative Zoology; Honduras, Depto. Cortes, 12 miles ne of La Lima; collected by E. Bangs 10 March 1928; reported in Lousada and Howell 1997).

Mass: 517 g (n = 1, male, oratrix; Binford 1989)