Many western hummingbirds are remarkably tolerant of sub-freezing (and even, for a few days at a time, sub-zero) temperatures. This makes sense, since many of them nest in cold climates, including elevations near timberline in the Rockies or Cascades, or as far north as southcentral Alaska. Rufous hummingbirds may return to their nesting grounds in Alaska or British Columbia as early as April, when the snow still lies deep in the forest. Anna's hummingbirds routinely winter as far north as British Columbia, coming to snow-covered feeders.
One important adaptation these western hummingbirds possess is the ability to go into a deep, hibernation-like torpor on cold nights, as a way of saving energy. The hummingbird will find a perch for the night, fluff its feathers and dramatically lower its body temperature from a normal high of about 102 F to just 54 F. To all appearances, the hummer looks dead, frozen to the branch, but come morning it will begin shivering, rousing itself to normal activity within a few minutes. (Ruby-throated hummingbirds possess this ability only to a degree, although they are hardier than many people assume....Show more →
E-M1MarkIIM.300mm F4.0 + MC-14 lens420mmf/11.01/250s2500 ISO0.0 EV
E-M1MarkIIM.300mm F4.0 + MC-14 lens420mmf/5.61/500s2500 ISO-0.5 EV