The Andean Hillstar (Oreotrochilus estella) is a small hummingbird found in the Andes mountains of South America. With its vibrant green plumage and long, curved bill, this species is one of the most distinctive hummingbirds in its range.
The Andean Hillstar is a medium-sized hummingbird, measuring about 10-12 cm in length. As its name suggests, it is found in the Andes mountains, primarily in Peru, Bolivia, Chile, Ecuador and Colombia between elevations of 2500-4500 meters.
The species is placed in the genus Oreotrochilus, which contains 4 other similar Andean hummingbird species. Oreotrochilus hummingbirds are characterized by their long, decurved bills and extensive green plumage. Among its congeners, the Andean Hillstar can be distinguished by the bronze-green crown and bright green throat of the male and the buffy tips to the tail feathers of the female.
The Andean Hillstar inhabits the windswept, treeless scrub habitat of the high Andes known as puna. Here it feeds on nectar from flowering plants such as red-hot pokers and giant senecios. Like other hummingbirds, it can hover in place and fly backwards using its specialized wing motions. The long bill allows it to access nectar from long tubular flowers.
Description and Identification
The adult male Andean Hillstar has vibrant green plumage on its head, back, rump and underside. The crown often has a bronze-green sheen. The throat and forehead are even more intensely colored green. The tail is blackish with white tips to the outer 3-4 feathers. The bill is long, straight and black. The legs are also blackish.
The female Andean Hillstar is similar to the male, but has buffy white tips to the outer tail feathers instead of white. The throat is also buff colored instead of bright green. Juveniles resemble adult females but with even more buffy spots below and buff fringes to the back feathers.
Andean Hillstars produce a high-pitched, squeaky call described as “sip” or “seep”. They are active and noisy birds, aggressively defending flowering patches from intruders.
Distribution and Habitat
Andean Hillstars are found along the Andes mountains from central Peru to northern Chile and Argentina. Their breeding habitat is high elevation scrubland and grassland from 3500-4500 meters elevation.
This harsh, windswept puna habitat has low vegetation, cacti, boulder fields and mountain cliffs. Temperatures are cold and oxygen is scarce. Despite the challenging conditions, Andean Hillstars thrive in the puna, feeding on flowers such as the red-hot poker Tritelia and giant groundsel Senecio. They are also attracted to human settlements and gardens at these elevations.
Outside the breeding season, Andean Hillstars may descend to lower elevations of 2500-3500 meters. But they primarily remain in high altitude habitat. Their range overlaps with the smaller Oasis Hummingbird between about 2000-3500 meters elevation.
Diet and Feeding
Like all hummingbirds, Andean Hillstars feed on flower nectar and small insects. Their long curved bill allows them to access nectar from long tubular flowers. Common food plants include the red-hot poker (Tritelia), giant groundsel (Senecio) and various flowers in the lupine and fuchsia families. Andean Hillstars use their slender bill to lick nectar from these flowers while hovering in front of the bloom.
Insects such as small flies and gnats make up an important source of protein in their diet. Andean Hillstars hunt insects by gleaning along foliage and in midair. Their flight muscles allow them to hover and fly backwards as they pick insects off leaves or capture them on the wing.
Reproduction and Life Cycle
Andean Hillstars breed between August and December in the southern hemisphere spring and summer. As in other hummingbirds, the males perform elaborate courtship flights to impress females. Once paired, the female builds a tiny cup nest out of soft plant down, spider webs and lichen on a rocky outcrop or cliff face.
She lays just two small white eggs. Only the female incubates the eggs, for about 16-17 days. Once hatched, both parents feed the chicks with regurgitated insects and nectar. The young leave the nest at 20-23 days old.
Threats and Conservation
With its remote habitat, the Andean Hillstar is not considered globally threatened. Its population appears stable and may even be increasing as the species adapts to human settlements and gardens. However, it has a limited global range and could suffer declines from severe weather or habitat loss at high elevations.
Changing climate patterns may also impact flowering cycles and food availability. The Andean Hillstar is not considered an endangered or threatened species, but habitat protection will be important for its long-term survival. Parts of its range are found in protected areas such as Peru’s Manu National Park. Ecotourism may help provide incentive to preserve puna habitat.
– The Andean Hillstar has sometimes been reported at elevations up to 5100 m, among the highest of any bird species. Their adaptations allow them to thrive in low oxygen and cold temperatures.
– Males perform elaborate courtship displays, flying in U-shaped or circular patterns to impress females. They also arch their tails, spread their tail feathers and dive to show off for potential mates.
– Andean Hillstars build tiny, thimble-sized nests out of plant down held together by spider webs. The tiny nests are built on rocky ledges or against cliffs.
– Their long, specialized beaks and extendable tongues allow them to feed on flowers with deep, tubular blossoms. This gives them exclusive access to nectar other birds can’t reach.
– Known as “estrellas” in Spanish, they are one of many brightly colored hummingbirds found across the Andes Mountains. About 140 hummingbird species are found in South America.
In summary, the Andean Hillstar is a fascinating hummingbird specially adapted to the harsh conditions of the high Andes mountains. With its unique appearance and behaviors, this vibrant green species stands out even among Andean hummingbirds. Conservation of its remote puna habitat will ensure the continued survival of the Andean Hillstar and protection of the wider biodiversity of this extreme ecosystem.