Crimson-collared tanagers average long. The adult plumage is black with a red collar covering the nape, neck, and breast (remarkably similar to the pattern of the male crimson-collared grosbeak). All tail coverts are also red. The bill is striking pale blue and the legs are blue-gray. In adults, the irides are crimson, contrary to what is shown in Howell and Webb. Females average slightly duller than males, but are sometimes indistinguishable from them. Juvenile birds are similar except that the hood is dull red, the black areas are tinged with brown, and the breast is mottled red and black. Young birds also have a duller bill color.
