The Plush-crested Jay has a dark violet blue back, a black bib, pale yellow underparts and nape, spots of blue above and below the eye, and a short crest of stiff, “plush-like” crown feathers. It is similar in appearance to several other species of large, blue and white Cyanocorax jays, such as the White-tailed Jay (Cyanocorax mystacalis), White-naped Jay (Cyanocorax cyanopogon), Black-chested Jay (Cyanocorax affinis), Cayenne Jay (Cyanocorax cayanus), and the Curl-crested Jay (Cyanocorax cristatellus).
The Plush-crested Jay is similar to several other species of "pied" Cyanocorax jays, such as the White-tailed Jay (Cyanocorax mystacalis), White-naped Jay (Cyanocorax cyanopogon), Black-chested Jay (Cyanocorax affinis), Cayenne Jay (Cyanocorax cayanus), and the Curl-crested Jay (Cyanocorax cristatellus). The Curl-crested Jay, the distribution of which overlaps in part with that of the Plush-crested Jay, is the only one of these similar species to have a definite crest. The crest of Curl-crested is on the forecrown, however, and is long and slender; this is very different from the short, bushy crest on the rear of the crown of Plush-crested Jay. Additionally, the Curl-crested Jay has a dark iris, white underparts, and lacks pale spots on the side of the head.
The distribution of the White-naped Jay closely approaches, or perhaps even meets, that of the Plush-crested Jay. White-naped Jay is mostly brown, not blue above, lacks the bushy crest on the rear crown, has a whiter band on the nape, and has whiter underparts.
The White-tailed Jay, Cayenne Jay, and Black-chested Jay do not overlap geographically with the Plush-crested Jay. Those species have similar black bibs, but are more extensively white and lack the blue facial markings of chrysops.
The following description is based on Goodwin (1976) and Madge and Burn (1994):
Adult: Feathers of the forecrown stiff and tufted. Feathers on the crown velvety, less stiff, and elongated on the rear crown, forming a distinctive bulge. Head, neck and upper breast deep black, other than for a deep blue patch on the malars, and small violet blue or greenish blue spots above and below the eye, the latter spot contiguous with the malar stripe. Nape pale, almost whitish, blue shading to dark violet blue on the hind neck. Upperparts and wings dark violet blue. Rectrices dark violet blue with broad pale yellow or whitish tips; this pale terminal band is ca 2.5 cm broad on the central rectrices and up to 5 cm broad on the outer rectrices. Lower breast and belly creamy yellow.
Juvenile: Lacks the pale spots above and below the eye, and the malar stripe is vestigial.
Immature: Similar to adult, but the pale eye spots are small and drab.
Little information. Attains definitive plumage following the second prebasic molt (Madge and Burn 1994). Piratelli et al. (2000) report molt of the remiges in Mato Grosso du Sul, Brazil, in November, January, and March, and molt in body plumage in March and June.
Data from Goodwin (1976) and Madge and Burn (1994):
Iris bright lemon yellow to pale yellow.
Bill black or brownish black
Tarsus and toes black or brownish black.
Total length: 35.5 cm (Ridgely and Tudor 1989), 36 cm (Madge and Burn 1994)
Linear measurements (from Madge and Burn 1994, for nominate chrysops; sample size not stated):
Wing length: 146-165 mm
Tail length: 155-179 mm
Bill length: 30-32 mm
Tarsus length: 42 mm
Males average larger than females in linear measurements (Madge and Burn 1994).
Mass: mean 140.3 g (range 127-158 g, ± 9.8, n=8, sex undetermined, Mato Grosso do Sul, Brazil, Piratelli et al. 2001); mean 166 g (range 154-170 g, n=21, sex undetermined, Argentina; Fiora 1934); 1 male 160 g, 1 female 138 g (Rio Grande do Sul, Brazil; Belton 1985).