Finding the tiny dinosaurs in hummingbirds

Hummingbirds wear a public image of fragile, ethereal beauty: tiny jewels whirring through the air, occasionally pausing to drink daintily from a flower. Their unusual appearance supports this: the iridescent feathers, the long dainty bill, the near-invisible feet all make them seem quite apart from the everyday world of animals who don’t shimmer in the sun and do have feet.

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80% gemstone, 15% fairy from a storybook, only maybe 5% actual bird. He doesn’t even have feet! (Yes he does.)

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But hummingbirds, like all birds, evolved from dinosaurs. Hidden under that glimmering exterior is a tiny, fierce raptorial dinosaur.

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Avian flight III: hummingbird flight

Hummingbirds are amazing fliers. They fly forward at up to 26 miles per hour; they fly backward; they hover. They beat their wings 50 times a second, so all you see is a blur, with that enameled little body floating serenely in the middle. They are flight acrobats. They are flight artistes. How do they do that?

Rufous Hummingbird. Photo by M. LaBarbera

Rufous Hummingbird. Photo by M. LaBarbera

It helps that they are quite small. The amount of power that you can get out of your muscles increases as muscle mass (size) increases—bigger muscles, more power—but the amount of power increases less quickly than mass does. That is, if you double the size of the muscle, you get less than twice the amount of power out of it. This means that as an animal gets bigger, its ratio of muscle power to muscle mass decreases. An ant can carry enormous things for its size. A small bird can generate enough power with its muscles to hold its own body aloft and still in the air—to hover. A California Condor? Not so much. Hummingbirds’ small size means that they are, relative to their own body mass, very strong.

Rufous Hummingbirds are small. Photo by M. LaBarbera

Small size is a Rufous Hummingbird’s secret weapon.
Photo by M. LaBarbera

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Spend your weekend watching these live bird cams

First, and undoubtedly oddest, is the Piip Show, which is a “bird reality show” (read: livestream from a birdfeeder shaped like a bar) from a Norwegian television network. Apparently this is an experiment in “slow tv,” which I did not know was a thing. Follow this link and click the red arrow in the bottom-left corner of the picture to watch live, or scroll down a few lines to watch a popular clip (the birds are at the end of the clip). As an American, I’m enjoying watching the exotic-looking-to-me birds like Blue Tits. Thanks to Rachel for the tip!

The Decorah Bald Eagles are back, and as I type this, a very small small grey-fuzzed chick is struggling to get out from under its rather bemused-looking parent.

The Cornell Lab of Ornithology maintains a number of excellent bird cams. My recent favorite has been the Laysan Albatross one on Kauai, HI, not least because the time difference means you can watch it in daylight even when it’s quite late for you if you live in the continental US. Also, the chick looks like a wet mop. The chick is named Kaloakulua and was recently identified as female. Sometimes she is visited by nonbreeding adult albatrosses doing lovely practice courtship dances, and it’s interesting to see how long the chick is left alone as the parents forage: sometimes they don’t return to feed her for weeks.

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