Andean Hillstar

**Andean Hillstar (Oreotrochilus estella)** The Andean Hillstar is a robust hummingbird species measuring approximately 12-13 centimeters in length. Males display iridescent green upperparts with a distinctive violet-blue gorget, while females exhibit more subdued bronze-green coloration with white underparts. This species demonstrates remarkable physiological adaptations to extreme altitude, including the ability to enter torpor during cold nights to conserve energy. As a nectar feeder, it plays a crucial pollination role for high-altitude flowering plants, particularly favoring tubular flowers that match its bill length. The Andean Hillstar inhabits the high Andes mountains across Peru, Bolivia, northern Chile, and northwestern Argentina, typically occurring between 3,500-5,200 meters elevation. It occupies puna grasslands, rocky slopes, and areas near glacial lakes, representing one of the highest-altitude resident hummingbird species globally. Climate change poses the primary threat to this species through rising temperatures that force populations to migrate to increasingly limited higher-altitude habitats. Habitat degradation from mining activities, overgrazing by livestock, and human encroachment into high-altitude areas further compress available territory. The species' specialized high-altitude adaptations make it particularly vulnerable to environmental changes. Conservation efforts remain limited, with most protection occurring within existing protected areas across its range. Research initiatives focus on understanding population dynamics and climate change impacts, though comprehensive surveys are challenging due to the remote, harsh terrain the species inhabits. The current outlook remains uncertain due to insufficient population data, though continued climate warming and habitat pressures suggest ongoing challenges for this high-altitude specialist.