The Bushy-crested Jay is a large, long-tailed jay. Nominate melanocyaneus of Guatemala and El Salvador is mostly blue, with a black head, chest, bill, and legs, and yellow eyes. The subspecies found in Nicaragua and Honduras, chavezi, has a darker belly. Juveniles have brown, rather than yellow, eyes and duller plumage.
The Bushy-crested Jay is very similar in appearance to the other Central American blue-and-black jays: San Blas Jay (Cyanocorax sanblasiana), Yucatan Jay (Cyanocorax yucatanicus), and Purplish-backed Jay (Cyanocorax beecheii). The geographic range of the Bushy-crested Jay does not overlap with any of these species, however. The Bushy-crested differs from the other three species by its dark tarsi; it also is smaller than Yucatan and Purplish-backed jays, although it is about the same size as the San Blas Jay. The blue belly of nominate melanocyaneus also distinguishes it from the other species, which have black underparts.
Adult: The Bushy-crested Jay is named for the bushy crest, although this typically is held flat (Howell and Webb 1995). This species has a relatively long, graduated tail (Madge and Burn 1994). The sexes are similar in appearance (Madge and Burn 1994). The adult has a black chest, head, and legs with a dull blue belly and undertail coverts and a bright blue tail and upperparts (Howell and Webb 1995). The underparts, upperparts, tail edges, and eyes have sometimes been described as having a greenish tint (Goodwin 1976).
Juvenile: The juvenile has a dark gray head and chest, smoky gray underparts, dull blue upperparts, and a blue tail with blue wings (Howell and Webb 1995).
Formative Plumage: Acquired within a few weeks of leaving the nest. The plumage is similar to that of the adult, although with less of a sheen. Birds at this age also differ from adults in soft part colors; see Bare Parts. It has been hypothesized that delayed maturation in certain visual characters may serve to integrate young birds into the social groups (Peterson 1991). Retaining juvenile characteristics is theorized to ease the incorporation of the young birds into large social groups because juveniles are often shown less aggression than adult birds (Peterson 1991). While many Cyanocorax jays exhibit delayed maturation in beak and eye color, a relationship was not found between the degree of sociality and delayed maturation of these characters (Peterson 1991).
The molts are described by Hardy (1973), based both on examination of museum specimens and on a small number of individuals raised in captivity.
First basic (prejuvenal) molt: complete.
Preformative molt: Incomplete, limited to the body. Completed by early December, at least for members of the first brood.
Prebasic molt: All subsequent molts are complete prebasic molts.
The soft part colors vary with age:
Iris: Yellow in adults. The iris of hatchlings and of juveniles is dark brown. The iris remains dark, an olive-brown, through the first year. By the second year, the iris is yellowish, and reaches the adult color by the third year.
Bill: Black in adults. The bill of hatchlings is yellowish-horn, with a darker tip. The bill begins to darken, from the tip towards the base, within a few weeks of leaving the nest. A pale base to the bill may persist through the first year. The bill attains the adult color by the second year.
Tarsus and toes: Black in adults. The tarsi and toes are dull blackish-gray or dark gray in juveniles, and are dull black through the first year. The tarsi and toes attain the adult color by the second year.
Total length: 28-30 cm (Madge and Burn 1994), 30.5-33 cm (Howell and Webb 1995).
Wing length: 130-139 mm (Madge and Burn 1994)
Tail length: 133-153 mm (Madge and Burn 1994)
Bill length: 25-28 mm (Madge and Burn 1994)
Tarsus length: 39-42 mm (Madge and Burn 1994)
Mass: mean 101 g (range 79.8-115 g, n=16; Dunning 2008); 103-115 grams (Madge and Burn 1994)