Violet-tailed sylph  (Aglaiocercus coelestis)

A stunningly beautiful hummingbird of South America, the violet-tailed sylph is named after the striking tail of the male: an extremely long, deeply forked, metallic violet plume of feathers, tipped with blue (2). The remainder of the male's plumage is equally as beautiful, shimmering iridescent green on the upperparts, turning slightly darker on the underside, and with patches of violet-blue feathers adorning the throat and the rump (2). Female violet-tailed sylphs are a little less striking than the males, as they have a short, unforked, bluish-green tail, with white tips to the outer tail feathers. They also differ by having a glittering blue crown, a white throat patch spotted with green that blends into a white breast, and orangey coloured underparts (2). Young violet-tailed sylphs are dull green on the upperparts and buffy-green on the underparts (2). Two subspecies of the violet-tailed sylph are recognised; Aglaiocercus coelestis athereus differs from Aglaiocercus coelestis coelestis by having a patch of green, instead of violet-blue, feathers on the throat, and a lighter scattering of green spots on the female's throat (2).