The Rufous-tailed Hummingbird (Amazilia tzacatl) is a medium-sized hummingbird which breeds from east-central Mexico, through Central America and Colombia, east to western Venezuela and south through western Ecuador to near the border with Peru. The larger Escudo Hummingbird from Isla Escudo de Veraguas in Panama is commonly considered a subspecies of the Rufous-tailed Hummingbird.

This is a common to abundant bird of open country, river banks, woodland, scrub, forest edge, coffee plantations and gardens up to 1850 m (6000 ft).

The adult Rufous-tailed Hummingbird is 10-12 cm (4-4,8 in) long and weighs approx. 5.2 g (0,2 oz). The throat is green (edged whitish in the female), the crown, back and flanks are green tinged golden, the belly is pale greyish, the vent and rump are rufous and the slightly forked tail is rufous with a dusky tip. The almost straight bill is red with a black tip; broadest on the upper mandible, which may appear all black. Immatures are virtually identical to the female. The call is a low chut, and the male's song is a whistled tse we ts' we or tse tse wip tseek tse.

The female Rufous-tailed Hummingbird is entirely responsible for nest building and incubation. She lays two white eggs in a compact cup nest constructed from plant-fibre and dead leaves 1-6 m high on a thin horizontal twig. Incubation takes 15-19 days, and fledging another 20-26.

The food of this species is nectar, taken from a variety of flowers, including Heliconias and bananas. Like other hummingbirds it also takes small insects as an essential source of protein. Rufous-tailed Hummingbirds are very aggressive, and defend flowers and scrubs in their feeding territories. They are dominant over most other hummingbirds.