Chilean woodstar

The Chilean woodstar (Eulidia yarrellii) is a Critically Endangered species of hummingbird in tribe Mellisugini of subfamily Trochilinae, the "bee hummingbirds". It is the only species placed in the genus Eulidia. It is endemic to Chile though there are unconfirmed reports from southern Peru. The species' name commemorates the English naturalist William Yarrell.

The Chilean woodstar is 7.5 to 8.0 cm (3.0 to 3.1 in) long and weighs 2.3 to 2.6 g (0.081 to 0.092 oz). It is the smallest bird in Chile. Both sexes have a short black bill. The adult male is iridescent olive green above and white below. Its gorget is reddish-purple and blue, but often appears blackish. The central tail feathers are very short and green; the outer ones are longer, blackish brown, and curve inwards. Females are also olive green above but are mostly very pale buff below, darkest on the belly and thighs. Their tail is short and slightly graduated with green central feathers; the outer ones are black with buff bases and wide white tips. Immature males are similar to the female, but have a mottled throat and may have elongated outer tail feathers.

The Peruvian sheartail (Thaumastura cora), which shares the Chilean woodstar's range and outnumbers it there, is very similar to the Chilean woodstar. However, the male sheartail has two elongated white feathers in its tail, while the female tends to have a whiter belly and a more buff throat than the woodstar. In contrast to the sheartail, the woodstar usually flies with its tail cocked and seldom pumps its tail.