Red-tailed Comet

Identification

The red-tailed comet is a medium-sized hummingbird with one of the most striking features in its family: a dramatically forked tail. Males are notably larger, measuring 19 to 20 cm in length with tails extending 7 to 10 cm, while females are considerably smaller at 12 to 14 cm overall. Both sexes are remarkably lightweight, weighing only 4 to 6.5 grams. Males display brilliant plumage with a shining green head, golden-green or emerald gorget, reddish-purple back and rump, and mostly green underparts. Their most distinctive feature is the long, deeply forked tail, which appears iridescent reddish-purple to green depending on light angle, with wide velvety black to dusky purple tips on the tail feathers. Females are considerably duller, with shining green head and back, reddish-purple rump, and pale buff underparts speckled with green on the throat and breast. Both sexes have a reddish-brown iris, black bill, and black legs. The subspecies S. s. sapho is paler overall, with golden-orange coloring replacing the reddish-purple of the nominate form.

Range & Habitat

The red-tailed comet is found in the Andes mountains, with populations confirmed in Argentina and Bolivia, and possibly occurring in Chile and Peru. The species inhabits arid montane scrublands on the eastern Andean slopes and within mountain valleys, preferring landscapes characterized by scattered trees, bushy understory, and dense tangles in ravines. It also occurs in Polylepis woodlands. Elevations range mostly between 1,500 and 4,200 meters, though the species has been recorded as low as 400 meters.

Behaviour & Diet

The red-tailed comet is primarily a year-round resident, though it makes elevational movements within its range, particularly in Bolivia. It feeds mainly on nectar, which it collects both while hovering and while perched, supplementing its diet with small arthropods captured in flight or gleaned from vegetation. Males actively defend flower patches as feeding territories. The species produces a distinctive "short, rapid, jumbled chatter" thought to be its song, along with harsher vocalizations including "unmelodic tjrrrt" calls and "rather harsh tsha or zack notes."

Best Time & Places to See It

The red-tailed comet is considered fairly common throughout its main range in Argentina and Bolivia. Breeding seasons vary by location: October to December in Argentina and April to June in Bolivia, with activity potentially year-round at lower elevations. The species is most readily observed in arid montane scrublands and Polylepis woodlands between 1,500 and 4,200 meters elevation, where it can be found defending flowering patches. Early morning hours typically offer the best viewing opportunities.

Photography Tips

Photographers should focus on the male's dramatically forked tail and iridescent gorget, which change color dramatically with light angle—positioning yourself to capture the interplay of green and reddish-purple tones will yield striking images. The bird's preference for hovering and perching while feeding offers opportunities for both action and portrait shots. Look for males defending flower patches, where they may remain relatively stationary. High shutter speeds are essential to freeze wing movements, while careful attention to backlighting will reveal the metallic sheen of the head and gorget. The contrast between the brilliant male plumage and the subtle coloring of females offers diverse photographic subjects within a single species.