Flitting around its forest habitat, the violet-tailed sylph, like all hummingbirds, displays remarkable manoeuvrability, afforded by its unique wing structure and figure-of-eight wing-beat pattern (5). It forages near the ground, or sometimes up near the tree tops (2), hovering next to a flower to feed or clinging to the petals (2) (4). It feeds on the nectar of flowering vines, shrubs and trees (2), inserting its specialised bill into the flower to obtain the sugar-rich substance (5). On one flower, Macleania bullata the violet-tailed sylph has been observed piercing the long tube at the base of the flower to reach the nectar, leaving a conspicuous slit (6). Through this feeding, hummingbirds play an important role in the pollination of many plants in the tropics (7), but the violet-tailed sylph also feeds on insects, snatched from the air or plucked from vegetation (2).
Violet-tailed sylphs breed between October and February, when they lay a clutch of two eggs into a domed nest, built from moss and spider webs in a clump of moss and epiphytes. The female incubates these eggs for 15 to 17 days, with the young hatchlings fledging after just 26 to 30 days (2). Unusually, the violet-tailed sylph also constructs nests outside of the breeding period, in which it roosts at night. This has misled many scientists into thinking that this bird breeds year-round (2).
Male violet-tailed sylphs are known to be territorial, and will defend an area in which they feed (2) (7). The male’s dominance appears to be determined by the length of its stunning tail, with those with longer tails being dominant over those with shorter tails. Dominant males have been observed plucking feathers from the backs of subordinate males, sometimes leaving a white line down the bird’s back (7).