When hummingbirds fly to Colorado in spring, the weather does not always cooperate. Birds flying around feeders covered with snow are often the subject of social media posts. How do these wee birds manage to survive late snowstorms and freezing temperatures?
Hummingbirds, as it turns out, go into a state of nightly “torpor.” John K. Terres, author of “The Audubon Society Encyclopedia of Birds,” defined torpidity as “a state of inactivity that is brought about by certain physiological changes – greatly lowered heart rate, breathing rate, and metabolism, and a greatly reduced response to external stimulation.”
According to Hummingbird Market, birds will drop their metabolic rate to 1/50th of normal, and heart rates can slow from 1200 beats per minute to as low as 50 beats per minute. In this state of torpidity, breathing becomes irregular, with long periods of no breath at the lowest temperatures. While the broad-tailed population is considered stable, challenges do exist in the form of human structures, domestic and feral cats, natural predators, habitat loss, pollution and climate change.
While nature has equipped the tiny birds with outsized winter survival strategies, the rare hummer is born with a big disadvantage.
A hummingbird which had neither the orange cast of the territorial rufous or the emerald sheen of the common broad-tail made an appearance in Evergreen in July 2019. The dove gray and cream feathers of the hummingbird reflected a pigmentation abnormality similar to albinism. But because the bird had black, rather than pink, eyes, he was in fact “leucistic.” Leucism is defined as a “partial loss of pigmentation in a human or other animal, resulting in white, pale or patchy coloration of the skin, fur or feathers, but not the eyes.” The species of the bird was unknown but was likely a broad-tail or rufous based on the time of year. The pale colors are considered a disadvantage to long-term survival due to the increase in visibility to predators.
As hummingbird season nears, before preparing your feeders, consider this:
According to “Bird Watcher’s Digest,” naturally occurring flower nectar from native plants and small insects are the mainstays of a healthy hummer diet. Nectar at feeders is an approximation of natural flower nectar, just as fast-food burgers are an approximation of actual food. We owe it to our hummingbirds to offer the nectar in the proper ratio (4 parts water to 1 part sugar) and to keep our feeders clean. Even so, what we offer in our feeders is not as good as the “real thing.”
As well, bears will go to great lengths (and heights!) to reach hummingbird feeders, which may lead to unfortunate results.
Instead of setting out feeders, consider planting hummingbird-friendly flowers. To learn more, visit https://gilpin.extension.colostate.edu/programs/mtn-hort/hummingbird/
Evergreen is home to a lively bird-watching community. For more information on programs and membership at the Evergreen Audubon Society, visit evergreenaudubon.org. In May, this group will open the Evergreen Nature Center located at Evergreen Lake. Inside, visitors will find great information on not only birds but the many wildlife species that make the Evergreen area their homes.