Like most of the Coraciiformes, motmots nest in tunnels in banks, laying about three or four white eggs.
The Blue-crowned Motmot is 38–48 cm (15-19 in) long, depending on race. Nominate M. m. momotamay weigh as little as 77 grams (2.7 oz), while the Highland Motmot may weigh up to 175 grams (6.2 oz). The tail is very long with a bare-shafted racket tip. The upperparts are green, shading to blue on the lower tail, and the underparts are green or rufous depending on subspecies.
In all except the entirely blue-crowned subspecies coeruliceps, the central crown is black and surrounded by a blue band. There is a black eyemask, and the nape of momota is chestnut. The call is a low owl-like ooo-doot, although there are variations depending on the subspecies involved.
These birds often sit still, and in their dense forest habitat can be difficult to see, despite their size. They eat small prey such as insects and lizards, and will also regularly take fruit.