A species of Ecuadorean hummingbird native to the Andean high-altitude grasslands is unique for emitting the highest sound recorded in birds.
About 14cm (5.5in) long, the Ecuadorean hillstar (Oreotrochilus chimborazo) emits the sound to mark its territory and during courtship rituals.
Experts say it is not clear whether the birds can hear these sounds, which are made only by males. Their fundamental frequency of 13.4 kHz is far beyond the range at which most birds can hear – 2 to 8 kHz.
Their habitat is at an altitude between 3,500m and 5,200m (11,500ft to 17,000ft).
Ecuador, which is rich in biodiversity, is home to 132 hummingbird species out of the more than 300 in the world.