(Host) Do you think of hummingbirds as fragile, delicate creatures? Well, they are, but as commentator Ruth Page points out, they’re pretty good warriors, too.
(Page) One of the fightin’est, scrappiest, care-for-nobodys in this world is also one of the tiniest and most beautiful. Hummingbirds need so much energy to survive, they’ll peck, batter and scream as they beat off anyone trying to horn in on their sugar fix.
Some have been seen knocking another bird to the ground, then diving to peck it so it can’t fly back up. How mean can you get?
Hummingbirds can even chase away a bird as large as a crow. Hummers’ hearts beat twelve hundred times a minute. Their wings, with the most powerful muscles of any bird compared to their size, can beat at 2,208 revolutions per minute. With those lightning wings they can out-maneuver crows, no doubt leaving the big birds dizzy from trying to follow their zigs and zags. Hummers can fly backwards, too, and of course hover when necessary.
Each bird – the smallest weighs less than a dime – needs seven to twelve calories of energy a day. That’s equivalent to a 180-pound human eating 171 pounds of hamburger daily. Each little flyer must locate about a thousand flowers and drink its own weight in nectar daily. So they’re mean by raging necessity. Hummers have no social behaviors; survival is their only concern.
Hummers caught and banded by a scientist in Colorado recently had already flown about 2,000 miles from their winter home in Mexico, mating along the way with as many females as they could find. Gotta preserve those precious travelin’, fightin’ genes for future sons and daughters. And there’s not much time available: living so fast and furiously, these minute gems of flashing color live, on average, four years; some, only 1 year.
Males do most of their eating at night, to hold their daytime weight down and improve flight ability; after all they must chase off rivals and use calories mating. In the evening they’ll gorge for twenty or more minutes, filling their crops and increasing their weight by one-third.
Cold air drains downhill, so males fly up into the mountains at night where it’s a bit warmer. Every calorie counts. Females, though, must stay in valleys to protect babies in the nest. Some put nests on shorter branches so higher ones overhead will reduce heat loss at night. They makes nests of spider web silk, but will use human hair if there’s any around. If they are too chilly to be active at night, they can take time off. They cut body temperature by as much as a half. In torpor, their metabolism slows two to three times for every degree of Celsius temperature drop.
Hummers can’t survive on sugars alone; they also eat in-sects; their ability to hover lets them eat gnats and other tiny flyers right out of the air.
This is Ruth Page, talking about tiny delicate birds that live on such a fast track they must fight to survive, and eat as if they were in a contest at a summer Fair.