The Violet-crowned Hummingbird, Amazilia violiceps is a medium-sized hummingbird. It is 10 cm long and weighs approximately 5 g.
The bird is best distinguished by its violet colored cap, from where it gets its name. Adults are colored predominantly a dark olive green for their upperparts and tail. The underparts are predominately white. The bill of the male is straight and very slender. It is red in coloration, and shows a black tip. The female is less colorful than the male.
The breeding habitat is in arid scrub of southeastern Arizona in the United States to southwestern Mexico, (the Madrean sky islands), and it is typically a mountain species. Outside it's breeding range, it will occasionally stray from southernmost California to southwest Texas. The female builds a nest in a protected location in a shrub or tree. Females lay two white eggs. This hummingbird is partially migratory, retreating from northernmost areas during the winter.