Estrella de las colinas de garganta azul

The beautiful Blue-throated Hillstar was discovered in 2017 and officially described a year later. It’s only found on a few mountains in southwestern Ecuador, particularly the Cerro de Arcos (“Hill of Arches”). At over 12,000 feet, the hillstar’s windswept habitat, known as páramo, is a unique ecosystem of boggy grass and shrublands, studded with evergreen plants, mosses, and cacti.

The Blue-throated Hillstar belongs to a genus found only in open habitats of the high Andes. Like other high-elevation hummingbirds, the Blue-throated and other hillstar hummingbirds manage to thrive in this cold, oxygen-reduced environment thanks to several physical and behavioral adaptations.

Thin air makes hovering less efficient, so the hillstars tend to feed while clinging to or perching next to flowers. When drinking nectar, the Blue-throated Hillstar rarely hovers but instead grasps onto branches and flowers, stretching sideways or even hanging upside down like a chickadee. In general, these birds also spend a lot of time perched, saving energy for when flight is needed. At night, like others of its genus, the Blue-throated Hillstar probably roosts in crevices, where it enters a state of low metabolism known as torpor, when its normally high daytime metabolic rate drops and its heart rate slows to a crawl. Many other birds, including the Carbonero de montaña, use this survival strategy to conserve energy in cold conditions.

The Blue-throated Hillstar is only found in an extremely restricted area in the Andean highlands. Researchers estimate that there are only about a hundred individuals. Due to the ongoing destruction of its habitat and loss of favored nectaring plants, this tiny population is presumed to be in decline.

After its scientific discovery in 2017, ABC identified the Blue-throated Hillstar as a gap analysis species — an endangered bird currently lacking protection, which would likely go extinct without prompt conservation action. ABC partners with the Ecuadorian conservation nonprofit Fundación de Conservación Jocotoco to preserve the habitat that this species depends on.

As with most hummingbirds, the male and female Blue-throated Hillstar have strikingly different plumage, a form of sexual dimorphism. The male presents a bold combination of shining ultramarine throat, iridescent teal-green head and upperparts, and white underparts. A narrow black band separates the blue throat from the white breast, and a similar black stripe runs from just below this band through the center of the belly, ending between the legs. The female is a shining teal- to bronze-green above, including the head, with dusky markings on the flanks, chin, and upper throat, contrasting with the white base-color of the lower throat. Her throat is also speckled with iridescent blue and green feathers.

There are only a handful of recordings of the Blue-throated Hillstar, but their vocalizations seem to be similar to those of other hillstar species. Both sexes give a high, sharp rising whistle, as well as a rapid, stuttering chase call composed of quick whistled frequency sweeps, sharp percussive notes, and high whines.

The Blue-throated Hillstar has only been seen in the Andean páramo, high-altitude grassland, where they feed in patches of flowering shrubs. Recently, researchers have found that males and females may use different microhabitats, with males more often using shrubby habitats and females using more open grassland.

• Often found in Chuquiraga jussieui shrubs, a favored food source
• Also found along small creeks, perhaps to take refuge in inclement weather

The Blue-throated Hillstar was described to science in 2018, and the peer-reviewed literature contains only a handful of observations. As such, there are still many unknowns in this species’ natural history. For instance, there is essentially nothing known about this hummingbird’s breeding biology. However, other ecologically similar species in the hillstar genus may allow us to make some basic inferences.