High Altitude Birding: Broad-tailed hummingbirds come to Summit County
Summit County is home to a single nesting hummingbird species — the broad-tailed — and by now, they have returned from their winter range in the mountains of Mexico to begin breeding. Sugar-water feeders (add one cup of cane sugar to four cups of boiling water, stir and cool) supplement their natural nectar sources and provide us with endless entertainment and photo ops.
In July and August, we also see copper-colored rufous and diminutive calliope hummingbirds as they migrate south through Colorado, but summer nesting belongs to the broad-tailed. Absent in Summit County most of the year, this high-elevation hummer arrives in May and is gone by mid-September. Nesting coincides with flower nectar availability, especially red columbine, scarlet gilia, bearded tongue and Indian paintbrush.
As is the case with all hummingbirds, nest building, incubation, feeding and rearing of young are left to the mothers. Males trade feeding territory access for sex, establish no lasting relationships and spend their time picking fights at the local nectar bar. The females are probably happy these guys don’t hang out at home.
Both sexes spend the warm mountain days at lower, flower-blooming elevations, which become colder than higher habitat at night due to thermal inversion. The overworked females nest and remain in these colder nighttime spots, in order to stay close to food sources for their young. To deal with freezing nights, they insulate their nests and build them under protective overhanging branches. Both sexes use torpor to slow their heartbeat and maintain survival temperatures during extreme nights, but the self-centered males also high tail it upslope to get above the thermal inversion at night.
As is often the case, the male birds are the most colorful, sporting bright-red throats to complement their emerald backs. Females are much more drab, with no flashy red feathers, but in compensation, they don’t draw attention from hungry predators. Male broad-tailed hummingbirds also have a characteristic unique among North American hummingbirds: They signal their presence with a high-pitched, 6 kilohertz telephone-like ringing trill, created by the birds’ tenth wingtips as they show off for potential mates or aggressively dive-bomb competitors. If you’ve been outside next to a sugar-water feeder when one of these ringing males zips by, you’ll understand why other birds back off.
Of the 10,000 or so bird species in the world, hummingbirds are perhaps the most unique. Unlike any other bird, they can hover and fly forward, backward, up, down and even upside down. Their figure-eight wing beats reach a staggering 50 times per second, and they can fly faster than 30 mph. The species found in the United States don’t weigh much more than a penny, and yet some of them migrate nearly 3,000 miles twice a year.
In addition to nectar, they feed on similarly composed tree sap at wells drilled by sapsuckers and tiny insects or spiders. The 300-plus species found worldwide are all in the Western Hemisphere, from Canada to the tip of South America. Of these, just 18 species are found in the United States. The broad-tailed, Summit County’s only nesting hummer, is a perfect match for the High Country. They love thin air, breeding up to 10,000 feet, and they love our wildflowers, pollinating some of the prettiest. The males may be self-centered playboys, but they aren’t alone in that category. And don’t forget that signature, high-pitched wing trill, as unique as a High Country cattle brand.
Bob Bowers is a naturalist and freelance writer specializing in nature and travel articles. He writes a monthly birding column for an Arizona newspaper, lives in the mountain foothills near Tucson and spends much of his summer in Keystone. He writes a birding and travel blog, http://www.birdingthebrookeandbeyond.com, and his email is email@example.com.
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