The copper-rumped hummingbird (Amazilia tobaci) sometimes placed in the genus Saucerottia, is a small bird that breeds in Venezuela, Trinidad and Tobago, and has occurred as a vagrant on Grenada. It is a seasonal migrant in parts of Venezuela.
This hummingbird inhabits open country, gardens and cultivation. The female copper-rumped hummingbird lays its eggs in a tiny cup nest on a low branch, or sometimes wires or clotheslines. Incubation takes 16–17 days, and fledging another 19-23, and there may be up to three broods in a season. It is the predominant species of hummingbird in Trinidad and Tobago.
The copper-rumped hummingbird is 8.6 cm long and weighs 4.7 g. The bill is fairly long, straight and mostly black with some pink on the lower mandible. The adult has copper-green upperparts, becoming copper-bronze on the rump. The head and underparts are bright green, the thighs are white and the tail and legs are black. The sexes are similar.
The subspecies which breeds in Trinidad, A. t. erythronota, is smaller and has more bronzing on the upperparts than the nominate A. t. tobaci of Tobago. The latter race has occurred as a vagrant to Grenada. There are several other subspecies in Venezuela differing mainly size and in the colour of the rump and back.
The food of this hummingbird is nectar, taken from a wide variety of flowers, and some small insects. Copper-rumped hummingbirds perch conspicuously and defend their territories aggressively against other hummingbirds, bees, and larger bird species; this is especially during mating season, which is early in the year.
The call of this species is a chip, and the song is a high-pitched tyee-tyee-tyoo. source