White-sided Hillstar (Oreotrochilus leucopleurus) [XC895959]
by id from Reserva Provincial Divisadero Largo, Mendoza, Argentina (song)
White-sided Hillstar (Oreotrochilus leucopleurus) [XC625729]
by Ignacio Escobar from Laguna El Yeso, Chile (flight call, song)
Subspecies
Forms a superspecies with Andean Hillstar (Oreotrochilus estella), Ecuadorian Hillstar (Oreotrochilus chimborazo) and Green-headed Hillstar (Oreotrochilus stolzmanni), and all have been considered conspecific, but separated largely on morphological grounds. Andean Hillstar (Oreotrochilus estella) overlaps slightly with present species, and some hybridization reported, in spite of which present species is the form least frequently lumped into Andean Hillstar (Oreotrochilus estella).