The Trinidad Motmot is a typical motmot in general aspect: a large bird with a stout, black bill, and a long tail with a "raquet" tip. The back and wings generally are green, the upper surface of the tail is blue, and the underparts are deeply rufescent. The center of the crown and a broad line through the eye are black; there also is a broad blue line bordering the crown, which is light blue on the fore part of the head but that becomes dark blue across the rear of the crown. There also is a short black streak on the center of the breast.
The Trinidad Motmot is the only species of motmot found on Trinidad and Tobago, and so readily is identifiable. Distinguished from allopatric members of the "Blue-crowned Motmot" complex by the color of the underparts, which are deeper rufous, and are more extensively rufous, than in other members of the group.
The following descriptions are based on ffrench (1991) and Stiles (2009):
Adult: Sexes similar. Center of crown black. Broad blue circle ("diadem") around the sides of the head, just below the crown; on the forecrown and above the eyes, this band is light turquoise blue, but becomes dark blue across the nape. The rear portion of the "diadem" often has a narrow black border. Broad black stripe or "mask" across the face, beginning on the lores, extending back around the eyes, and terminating in elongated auricular feathers. The "mask" is bordered with blue to turquoise, relatively inconspicuous on the anterior and terminal portions of the mask, but the blue border is broad in the central portion of the "mask." There also is a diffusion of light blue or turquoise between the "diadem" and the rear portion of the "mask." Back and wings generally green; usually there is a rufous wash on the nape. Throat, breast, and belly dark rufous; flanks washed olive-green, and the breast (especially the sides of the breast) also may have a faint olive-green wash. Feathers in center of breast black, broadly margined with turquoise blue, forming a short black streak. Tibial feathers green to blue-green. Upper surface of tail green at base, shading distally to dark blue. Central pair of rectrices elongated, extending beyond rest of tail as narrow shaft and terminal racquet tips. Racquets are basally dark blue, with a broad black tip (covering the distal quarter to third of the racquet).
Immature: Similar to adult, but lacks the black breast streak.
Little information. Molt reported June-October; "it is a slow process, lasting at least 4 months" (ffrench 1991).
Data from ffrench (1991).
Total length: 46 cm
Wing length, males: mean 135.2 mm (range 133-138 mm, n=5);
Wing length, females: mean 137.9 mm (range 133-142 mm, n=7)
Mass, females: mean 111 g (range 99-133 g, n=6; the individual of 133 g was an "egg-laying bird"); unsexed, mean 111.7 g (range 89-130 g, n=9).
All data from ffrench (1991).