In addition to their behavioral adaptations for life above 3,500 meters (11,480 feet), these hummingbirds also have an assortment of morphological and physiological adaptations for living where the air is thinner, colder and oxygen-poor compared to sea-level. For example, these hummingbirds don’t fly as much as their lower-elevation cousins, but when they do fly, long wings and a robust tail create extra lift in the thin atmosphere. Additionally, since energy is precious and limited, these birds enter a state of hibernation known as torpor to survive frigid nighttime temperatures (more here). Torpor is a physiological state where hummingbirds’ high metabolism slows, their body temperatures drop and their heart rate comes to a near-halt to conserve energy.

“The hillstar hummingbirds occur in the most rugged, isolated, and inaccessible parts of the Andes, where they roost in caves, forage on the ground, and spend half their lives in hypothermic torpor, so the discovery of a new species in this group is incredibly exciting,” said Christopher Witt, Director and Curator of Birds at the Museum of Southwestern Biology and a hummingbird expert at the University of New Mexico, who wasn’t involved in the study.

“The location is fitting for a new species of hillstar, because it’s a remote, high mountain range that is isolated and is sandwiched between the ranges of two other hillstar species,” Professor Witt added. “The authors did a thorough job comparing the new form to its relatives in every respect.”

Not only does this bird look different from its closest relative, green-headed hillstar, Oreotrochilus stolzmanni, which has an iridescent green gorget, but genetic analyses and sonogram examinations of the birds’ calls confirm that this species is new to science. Additionally, the two species are separated by large tracts of unusable habitat.

Five groups of these blue-throated hillstars live in their remaining habitat, which occupies just a total area of about 100 square kilometers (62 square miles). Threats to the blue-throated hillstars’ habitat include cattle ranching, burning, agriculture, and gold and copper mining. Based on the number of male and female birds they observed in the field, and the lack of suitable feeding and nesting habitat in the area, Dr. Sornoza-Molina and his colleagues estimated there are somewhere between 250–750 individuals in the wild, with the distinct possibility that there are fewer than 500 individuals, so this species meets the criteria to be listed as Critically Endangered.

Dr. Sornoza-Molina and his colleagues collected a total of 7 hummingbirds — 4 adult males and 3 females — to be held at Museo Ecuatoriano de Ciencias Naturales for future reference and study. This raises the question: might removing 7 individuals from an already tiny population negatively impact their long-term survival? Wouldn’t it instead have been preferable and equally useful to substitute feathers and blood samples for future genetic work, along with vocal recordings, morphological measurements and lots of photographs of the birds for museum collections?