The Thing with Feathers (11 page)

It is natural to assume that wintering snowy owls are wasting away because they spend most of their day sitting and are often quite approachable. An adult snowy has few predators besides humans, so they can seem very tame, and they have little regard for the dangers of traffic—they are known for their habit of perching on highway shoulders, barely noticing
the vehicles speeding past. Wintering snowy owls spend 98 percent of their time sitting still during the day and may do most of their hunting after dark. In the far north, of course, owls must hunt during summer daylight and winter darkness alike.

Studying snowy owls is difficult because of their tendency to roam. One researcher staked out a population of 1,000 snowies for an Arctic summer only to find, frustratingly, that none of them were present the following year. Another researcher banded seven snowy owl chicks on Victoria Island in northern Canada, hoping to figure out where they ended up. Amazingly, three of them were relocated within seven months: one at Attawapiskat, Ontario (1,350 miles away); one at Clyde Forks, Ontario (1,950 miles away); and one at Sakhalin, Russia (3,450 miles away). The last one had traversed half of Arctic North America and crossed the brutal Bering Sea.

So we can theorize about the causes of irruptions, but their reasons remain as mysterious as the owls themselves. Nobody really knows why snowy owls sometimes appear south of their normal range. Maybe it’s because of crashes in lemming populations, maybe it’s because of peaks in lemming populations, and maybe it’s something else entirely. Because lemmings are so patchy, perhaps a more widespread effect—like weather—might better explain large-scale owl irruption events. In any case, the owls that occasionally show up south of Canada are in better shape than some news reports suggest.

In 2012, the
Weekly World News
announced its own theory. The self-proclaimed “world’s only reliable” news source reported that “hostile snow owls” were swarming the United States and “working with alien forces to attack American citizens.” According to the article, the owls were communicating with Gootans that landed on planet earth in November 2011 and who were also, incidentally, killing Peruvian dolphins.

Who can say otherwise? Next time you see a snowy owl, better keep a safe distance. Just in case.

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“NOT ALL THOSE WHO WANDER ARE LOST,”
J. R. R. Tolkien once wrote. Like many nuggets of bumper-sticker wisdom, the quip contains an element of scientific truth—and it is especially apt for snowy owls. These owls have perfected their nomadic lifestyle not as a stepping-stone to stability, but as an ultimate survival strategy. The snowy owl “appears to have reached a terminal point in its evolution,” author Karel Voous observed, suggesting that the bird’s drifting habits are the perfect response to an unpredictable Arctic environment. Snowies wander with a purpose.

Only recently have we begun to appreciate quite how much these birds meander. New satellite technology has radically changed our knowledge of the birds’ movements. When transmitters were first attached to several adult female snowy owls at their nests in Barrow, Alaska, in 1999, researchers were amazed to find that the owls took off in different directions after the nesting season, covering up to 1,960 miles to reach northern Siberia and Victoria Island, Canada. None of the owls returned to nest in Barrow the next year; instead, they spent the following summer between 390 and 1,200 miles away. Several crossed the Bering Sea multiple times, even lingering on sea ice for weeks on end. And none of them seemed to follow a regular migratory pattern. Though the owls sometimes returned to places they’d visited before, they didn’t commute between summer and winter ranges so much as wander an enormous swath of the Arctic, apparently looking for things to eat.

This study inspired others to track snowy owls. In 2008, one study in northern Canada found, unexpectedly, that six adult
female snowy owls spent almost the entire winter on sea ice, far from land. Lemmings don’t exist on frozen ocean, so the scientists concluded that the owls were targeting seabirds, such as eiders—a type of bulky duck—instead of small mammals. Snowy owls may not depend on lemmings as much as once thought; even in more usual tundra habitats, they have been documented preying on birds, foxes, and other animals. Their willingness to fly long distances over water and to live on sea ice suggests a certain previously unrecognized adaptability.

The king of snowy owl trackers is Norman Smith, director of a wildlife museum in Massachusetts, who, since 1981, has captured nearly five hundred individual snowies at Boston’s Logan Airport. Each winter, when snowy owls turn up on the tundralike airfield at Logan, Smith is called in to safely relocate the birds. He began applying satellite tags to owls in 2000, and the results are fascinating: Many of the snowy owls wintering in Boston return to the high Arctic, from northern Quebec across Hudson Bay to Canada’s Nunavut Province, in good health after spending their winter so far south. Most of them don’t return to Massachusetts, though a few do. Smith caught one owl at Logan sixteen years after he first banded it there, setting a record for the oldest known wild snowy owl. (Satellite transmitter batteries last only one to three years, so it’s hard to know how long the owls live; in captivity, the record is twenty-eight years, and wild snowies might reach that age, too.)

Additional satellite studies in Europe and the North American Arctic have confirmed that healthy adult snowy owls habitually wander thousands of miles, which sheds new light on the birds that show up south of Canada. In the life of a snowy owl, it’s no big deal to fly that far; it’s just that they don’t usually fly that far south, where we can see them.

Such wanderlust is rare in a wild animal, but a few humans
can probably relate. Who hasn’t dreamed of disappearing over the horizon? For snowy owls, pulling up stakes isn’t a vague fantasy—it’s how they survive.

The word
wanderlust
can be traced to apprentices in medieval Germany who journeyed from town to town, gaining practical skills before becoming master craftsmen. A similar tradition still exists in France, where young
compagnons
travel the country to work in communal houses, in what’s known as the Tour de France (a pursuit that preceded the unrelated Tour de France bicycle race). Many world cultures have developed traveling coming-of-age traditions, from Australian Aboriginal walkabouts to Native American vision quests and Amish Rumspringa, which could be compared to young snowy owls’ gadding about after leaving the nest. But the wandering instinct goes deeper with snowy owls. They seem to be deeply nomadic by nature—more nomadic than humans, with some notable exceptions.

In 1995, a cover article in
New Internationalist
magazine estimated that between 30 and 40 million people in the world are nomads, and most of them are shepherds or herders (virtually all traditional hunter-gatherers have succumbed to modern ways). Like Arabian Bedouin herders, Mongolian tribes, and African Tuaregs, they keep no permanent homes, preferring to stay on the move. The author noted that most nomadic people “live in marginal areas like deserts, steppes and tundra, where mobility becomes a logical and efficient strategy for harvesting scarce resources spread unevenly across wide territories.” He could easily have been talking about snowy owls. In the same environments, it seems that humans and Arctic owls have adopted the same survival strategy.

Some people seem to be more inclined to wander than others. This trait could be coded in our genes, and may date back
to our distant ancestors. Genetic evidence indicates that modern humans left their African home to colonize the world, starting between 338,000 and 60,000 years ago. Why did those first people go? Were they more adventurous than the ones who stayed behind? Perhaps restlessness has a genetic component. If so, emigrants would be expected to establish populations with more wanderlust in their DNA than those back at home. Scientists have identified one particular allele, called 7R, of our DRD4 gene that may fit this description; it has been linked to attention deficit disorder and attraction to novelty, earning its nickname: the risk gene. Research has documented that people with the 7R allele take 25 percent more financial risk than those without it. Tellingly, the allele tends to be more concentrated in recently established populations (in terms of historic human expansion): Most people in the Americas have it, a few in Europe do, and it is rare in parts of Asia. People with this “wanderlust gene” may be literally hardwired to seek new experiences.

Do snowy owls have a wanderlust gene? They seem to feel the imperative to move as a powerful force, and it’s likely to be driven by instinct, honed by aeons of following fickle food supplies. Maybe someday we’ll know exactly what drives them on. In the meantime, whenever one of these ghosts of the white Arctic materializes someplace new, all we can do is appreciate the visit—because soon enough the owl will drift back over the horizon, leaving only fleeting memories behind.

hummingbird wars

IMPLICATIONS OF FLIGHT IN THE FAST LANE

L
iz Jones, proprietor of the Bosque del Río Tigre Sanctuary and Lodge in Costa Rica, has given up on feeding hummingbirds near her house.

“We put up our first sugar-water feeders about ten years ago,” she explained as we sweated one morning in the tropical heat outside the lodge’s lush front entrance. “It took several months for the birds to discover the feeders, but when they did, they were quite active. We had nine different species of hummingbirds making regular visits, and many of them nested in our garden.”

I could imagine how awesome this must have been. Because the feeders were in plain sight of the outdoor dining area, guests could watch the action as they ate their meals. Birders delighted in seeing their first-ever bronzy hermits, charming hummingbirds, long-billed starthroats, violet-crowned woodnymphs, and white-necked jacobins as they sipped their wine each evening.

Things went well with the feeder setup for a couple of years, until a feisty rufous-tailed hummingbird arrived. Four inches long and the weight of a nickel, he was handsome enough, with an iridescent green body, red lance of a beak, and orange-brick tail. But he was also meaner than all the other hummingbirds and never let anyone forget it. When he wasn’t gorging himself on sugar, the aggressive hummer spent almost all his time chasing everyone else away; this guy was the tiniest bully Liz had ever seen.

She tried moving the feeder, but he just moved with it. She tried putting out more feeders so he couldn’t possibly guard them all, but another rufous-tailed showed up and they joined
forces to defend against all comers, in all corners of the garden. The yard rang constantly with the sound of miniature aerial dogfights. She tried taking down all her feeders but one, thinking that the rufous-tailed would be overwhelmed by the other hummingbirds flocking to a single spot, but that just made it easier for him to fend them off. She even tried putting a feeder inside the lodge. A shy long-billed hermit learned to dart indoors for quick sips, but, lamentably, the other tropical hummingbirds couldn’t figure it out.

Pretty soon, the other hummingbirds stopped visiting entirely, leaving the rufous-tailed to sit, hour after hour, next to a lonely feeder. Doubtless, he enjoyed his life, king of an unlimited supply of food, but he wasn’t very entertaining for visiting birders.

“It was boring,” Liz said after she’d told me the whole story. “The rufous-tailed chased the others away, so instead of a buzzing hummer setup, we eventually just had this one bird, day after day.”

After five years, several more rufous-tailed hummingbirds arrived. Between them, they wouldn’t let a single other hummer anywhere near the lodge, much less the feeders. Where several species used to nest among the flowers in the garden, now there was just one.

Liz tired of pampering her resident bullies. She took down the feeders and never tried attracting hummingbirds again. By eliminating the feeder setup, she hoped to return to a more balanced mix of hummingbirds around the lodge, like there had been before the feeders went up. Some of the shyer hummers did return, but only gradually.

It was all very vexing. The feeders supplied unlimited nectar, and when they were nearly empty, Liz always refilled them. If the hummingbirds could just get along, they could eat all they
wanted without wasting energy on fighting. Why were they so selfish? Hummingbirds are supposedly smart—they may have the largest brain size, relative to body mass, of any bird in the world—but they weren’t acting logically. It didn’t make sense.

—

BECAUSE THEY ARE SO TINY
, hummingbirds are often described in superlatives. They are the world’s smallest birds and the world’s smallest warm-blooded vertebrates (besides a couple of obscure species of shrew). The bee hummingbird, which lives in Cuba, weighs as little as 1.8 grams—about a third as much as a sheet of printer paper. You could mail sixteen of them for the price of a single postage stamp.

Most hummers aren’t quite that teeny, but they’re all small. Of about 330 species of hummingbirds living between Alaska and Chile, the largest, the giant hummingbird of high-elevation Andes woodlands, could still be covered by that same first-class stamp. Not that airmailing hummingbirds would give them much of an edge; the ruby-throated hummingbird routinely flies more than five hundred miles nonstop across the Gulf of Mexico during its spring and fall migrations, taking about twenty hours to do so, and the rufous hummingbird, which commutes annually between Mexico and Alaska, makes the longest flight, relative to body length, of any bird in the world.