War Bird: An essay on robot hummingbirds

by Eric Wagner

Probably he was big
As mosses, and little lizards, they say were once big.
Probably he was a jabbing, terrifying monster.

-- D.H. Lawrence, "Humming Bird"

The other day, a friend of mine sent along a story he thought I'd enjoy. It described how some engineers had developed a robot they called the Nano-Hummingbird. Barely 3 inches long and weighing less than 1 ounce, the robot could maneuver like a hummingbird –– even hover like one. In the video that accompanied the story, a man piloted it around an office park, making it peek in through a second story window, enter a building and buzz around its halls.

The research team had received funding from the Defense Advanced Research Projects Agency, or DARPA, which envisioned robo-hummingbirds flitting through suspected nuclear sites, or sending back images of enemy positions via tiny cameras in their throats. The robot bore such an "uncanny resemblance to a real hummingbird" that it would be able to do these things unnoticed, or so the engineers hoped, although one wag noted that since hummingbirds occur only in North and South America, the thing might look out of place in current global hot spots.

The DARPA brain trust is notoriously eccentric, and it has of late shown a peculiar fondness for animals. Where others look at the wild and see natural history, these engineers see a rich and untapped vein of martial prowess. In a few clicks, I learned that DARPA-designed robot dogs have hauled Army gear across uneven terrain. A robot cheetah has already set a speed record, galloping on a treadmill at almost 20 miles per hour. A robot gull can flap and fly, and is hailed as the future of aerial drones.

There are, no doubt, many other such beasts, but I had seen enough mechanized wildlife for one day, and so I went outside to check the mail. As I walked up the road, a red glint caught my eye. Perched in one of the neighborhood maples was our resident Anna's hummingbird. The tiny emerald bird, its iridescent head flashing in the sun, sitting on a branch that was leafing new green, against a cloudless spring sky -- it made for a gentle and reassuring tableau. I felt myself relax. Here was the thing itself, not some cyborg approximation of it.

It being spring, the hummingbird was chittering merrily away. When it saw me, it gave a little chup! and lifted off from its branch. Hummingbirds are feisty creatures, and quite territorial. I have seen them pursue bemused crows, or dive at cats that had no idea they had entered contested ground. In like spirit, the Anna's hummingbird buzzed around my head, darting from spot to spot in a behavior called "strafing." It pointed its bill at me like a dagger, squeaking all the while.

Seeing that I was still uncowed, the hummingbird flew off to perform its dive display. Each species has a unique display, used to attract mates, or defend territory, or intimidate rivals. Male Anna's hummingbirds can rise as high as 130 feet in the air, hang for a moment, and then plunge toward the ground at almost 60 miles per hour, withstanding G-forces that ounce-for-pound are greater than those experienced by a fighter pilot. At the nadir of its dive, it flares its tail so that air rushes through the feathers, making a sharp, metallic tweet! Then it sweeps around in a great J, rises up again, repeats.

Now, I watched as the hummingbird began its display, belligerently claiming from me its small patch of earth and sky. I watched as it climbed, hung, plunged -- tweet! -- climbed, hung, plunged -- tweet! It went through the ritual several times, rising and falling, rising and falling, always with the same relentless precision. Just like a machine.

Eric Wagner writes about science and the environment from Seattle, where he lives with his wife and daughter.

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