Rufous Hummingbirds Turning Up in Unusual Places
Is climate change the reason, or are birders just paying closer attention?
So in 1979, after returning to Louisiana, Newfield obtained a banding permit and launched what she planned to be a five-year study. There was only one other hummingbird bander within a thousand miles. With the help of ornithologists like Remsen, Newfield learned anatomical terminology and measuring methods. And she experimented with nets and cages to capture the birds. That first winter, working in her own yard after the October departure of the ruby-throated for warmer climes, she banded 10 rufous and nine black-chinned hummingbirds. Since then she has banded thousands more. Over the years many of the banded birds returned. By the mid-1980s Newfield and others had extensive data to show beyond a doubt that several western species were finding good winter homes far from the Mexican hills where they were presumed to stay.
Were there simply more observers like Newfield to see birds that had been there all along? Or was there something new in the wind? "Clearly there's an increase," Remsen says. "I'd bet everything on it." Others, however, are not persuaded. Bob Sargent, a respected hummingbird bander in Alabama who learned his craft from Newfield, thinks that the birds simply went undetected for decades.
The trajectory of western birds like the rufous that show up in winter on the Gulf Coast is still a mystery. Some contend that they work their way east and then south along the Atlantic Seaboard as the push broom of winter sweeps down. Others believe they come down from the Great Lakes and the Midwest. Remsen poses what he calls the "wacko theory," that the birds follow their normal route from the Pacific Northwest to Mexico, then turn left to drift north and east to states like Louisiana. Reports of western species as far north as Massachusetts in the winter only muddy the picture. There's just not enough hard data to prove anyone right--yet.
Made up of some 350 species, the hummingbird family is one of the most diverse groups of birds in the New World. Their colors can dazzle, from the ruby-slipper red of the ruby-throated to the blue-and-green iridescence of the broad-billed. They can be as small as a bee or as large as a mockingbird. But their reputation as ethereal and gentle creatures is at odds with reality, if you listen to the humans who watch them.
"A whole subset of people see hummingbirds in the same category as fairies and angels and other mystical creatures," says Fred Bassett, a burly former fighter pilot who spends much of his time touring the country to band birds. He's particularly drawn to the varieties that summer in the West--especially the rufous, black-chinned, and calliope (only about 20 species traditionally venture north of Mexico). "But they are tough as nails. I've seen them chase people, dogs, and cats." Put out just one feeder in your yard, and a single hummingbird is likely to dominate, aggressively protecting the turf. Some species, like the buff-bellied, seem far from angelic. Says Remsen: "These are not tropical wimps."
The hummingbirds' small size--they typically weigh between three and six grams--is not to be confused with fragility. They flourish in the chilly highlands of the Andes, the tropical lowlands of Central America, the deserts of the American southwest, and the damp chill of the Alaskan coast. Some stay put; others migrate. Some, like the rufous, when they do migrate, fly as far as 5,000 miles from their winter homes to their nesting grounds. Their famously fast metabolism--the fastest of any animal in nature--makes for a constant and voracious appetite that puts a premium on moving. They are expert at snatching flies from spider webs, gorging on swarms of gnats, and of course, sticking their specialized beaks into flowers to suck nectar. One species in the Andes has a beak longer than its body. They have record hovering capabilities, and they can fly forward, backward, sideways, up, down--even upside down.
A day after the fierce storms have moved out of the Gulf Coast, Bassett is carefully untangling birds from nets on an Alabama barrier island a couple hundred miles east of the Owens yard. It is spring migration, and in the aftermath of the storm the nets are filled with an array of colorful bird species--including the occasional ruby-throated--exhausted from their 12- to 20-hour nonstop flight across the Gulf. He insists--and other hummingbird aficionados agree--that the creatures are not just aggressive; they are also smart. Bassett says that if he has let the feeder in his yard go dry, there are some hummers that will knock angrily against his kitchen window, trying to catch his eye as he gets his morning coffee. "They know who filled it," he says. "And they are as curious about us as we are about them."
But are they smart enough to outwit the potential disruptions posed by human development and a warming climate, threats that range from more ferocious hurricanes to dwindling habitat?
As with most topics concerning hummingbirds, there's more heat than light, in part because each species has its own special relationship to the environment. Rufous populations have fallen by more than half in the past 40 years, from 12 million to 5 million birds, according to Audubon's Common Birds in Decline report, largely as a result of logging and development of their breeding areas in the Pacific Northwest and their wintering grounds in Mexico. But if there is an increase among western species in the eastern United States, as Newfield and Remsen believe, it could be a sign that they are finding alternative migration paths and habitats. Whether that change might be due to more food or a temporary variation in the Gulf Coast climate is unclear.