Banding Hummingbirds to Solve their Mysterious Ways
People from all walks of life jump at the chance to hold these creatures.
The first faint hint of fall has blown in overnight, finally breaking the heat and humidity of the Mississippi summer. Hundreds of ruby-throated hummingbirds have also flown into town, tiny neotropical migrants from points as far north as Canada, heading south to Mexico, Guatemala, even Panama. Near where I'm standing, some of these hummers begin jockeying for space at a bank of feeders, becoming a blur of green, ivory, and crimson as they chase one another through the morning sunshine and dogfight high into the September sky.
As I watch, one of the combatants peels off from the skirmish and dives down to a feeder hung inside a green wire cage. A trapdoor drops behind it, and soon the bird is being measured and weighed by Fred Bassett, a retired Air Force lieutenant colonel and former fighter pilot who, no stranger to dogfights, has now turned his full-time attention to these miniature flying machines.
Bassett, one of only 100 licensed hummingbird banders in the United States and Canada, is banding ruby-throats at the Hummingbird Migration Celebration at Strawberry Plains Audubon Center, just outside of the historic antebellum town of Holly Springs, in northwestern Mississippi. Three thousand people have flocked to the 2,500-acre former cotton plantation on this autumn weekend. With his quick wit and easy manner, Bassett is entertains--as well as educates--a large crowd of them.
The ruby-throat in his hand is a member of one of the most diverse bird families in the Western Hemisphere. There are more than 300 species of hummingbirds--the name comes from the sound made by their rapidly beating wings--and most spend their lives hovering and darting through the forests of the American tropics. Fewer than 20 of these species regularly move north of the Mexican border, though, and the habits of these remain poorly known. The birds' tiny size and quick movements make them especially challenging to study. Banding is one way to keep tabs on hummers, so Bassett's handiwork is helping to unlock some of the secrets of these mysterious little migrants.
Using a special pair of pliers, he closes an aluminum ring--provided by the National Bird Banding Laboratory in Laurel, Maryland--around the leg of the ruby-throat. "Every hummingbird gets a band with a combination of a letter and five numbers that will never be used again," he explains to the people gathered around. If, in a year or two, this hummingbird is recaptured, the number on the band will be sent to the lab, along with information such as the bird's location and weight. This will reveal how the individual bird is doing, but it will also help paint a picture of the population in general. "It takes 5,500 of these bands to equal an ounce," Bassett says. He gently jiggles the bird's leg band, showing us that it's loose and doesn't impede the hummer in any way. "It's like wearing an anklet."
As he finishes banding each bird, Bassett allows someone from the audience to release it. This time he carefully places the hummer on my outstretched hand. Only a month or so out of the nest, the young male has not yet acquired the iridescent throat feathers of an adult but is still cloaked in soft greens and whites. The bird doesn't realize it is free and lies quietly as I cradle it in my palm.
The hummer and I gaze at each other. The bird's bright eye--surprisingly unafraid--seems to study me. I can feel the quiver of its heartbeat, which flutters 250 times a minute at rest and more than 1,200 times a minute when it flies. (By contrast, the average resting human heart beats 72 times a minute.) Suddenly the hummer lifts off and is gone, streaking back to the feeders. It takes a bit of me along with it.
These little birds have inspired a huge passion among those who study them--the majority of whom are not scientists supported by grant money but are, like Bassett, unpaid volunteers. Take Bob Sargent and his wife, Martha. At one time they were just two people who fed birds in their backyard in Clay, Alabama. "But we had questions, especially about hummingbirds, that we could not find answers to," says Bob. "We wanted to raise the window to where we could peek into their lives a little more. When you capture a bird and hold it in your hand, you really have an opportunity to examine it." So the Sargents found someone who could teach them to band.
From there "it kind of snowballed," Bob laughs. Today the former electrician and his wife run the Hummer/Bird Study Group, a nonprofit organization dedicated to researching hummingbirds and other neotropical migrants, and have become world-recognized authorities on ruby-throats. They have banded more than 30,000 hummers, and they train other people--including professional scientists--to band them, too. So far their 19 years' worth of data has been revealing. Ruby-throats are the only hummingbirds that nest east of the Mississippi, but the Sargents' banding network has documented 12 other hummingbird species, such as the calliope and Allen's, that have overwintered at least occasionally in the eastern United States.
Ned and Gigi Batchelder belong to the community of enthusiasts who study western hummingbirds. Like the Sargents, they have upended their lives to do hummingbird research. Five years ago the Batchelders--who were employed for 25 years in the energy industry--moved from Oklahoma to Montana, where they work winters at local jobs in order to spend all summer banding calliope, rufous, broad-tailed, and black-chinned hummingbirds.
Since the spring of 2001 the Batchelders have banded 6,000 hummers. The majority were rufouses and calliopes; the latter, just over three inches long, are the smallest long-distance avian migrants in the world. Every year calliopes tackle a perilous 5,000-mile round-trip migration, from the mountains of the western United States and Canada to south-central Mexico and back again. In 2003 the Batchelders recaptured 228 birds they had originally banded in the previous two years. The birds' "anklets" revealed a remarkable fact: After navigating across two countries, most of the banded hummers returned, almost to the day, to the exact gardens and yards where they had summered the year before.
The reason, says Jesse Grantham, former director of bird conservation for Texas Audubon, who is now working with the U.S. Fish and Wildlife Service to restore California condors, is that "hummers are trying to stick to a 10,000-year-old strategy of being at a certain place at a certain time, because that's when factors are ideal in those particular locations. The problem is that the habitat during this time period has totally changed."
Hummingbird festivals, such as the one Grantham started in 1988 in Rockport, Texas, and the annual celebration he started in 1999 at the Strawberry Plains Audubon Center, are timed to take advantage of this predictable peak migration. "Sometimes it takes a spectacle to get people excited about birds," says Madge Lindsay, the center's executive director (and the executive director of Mississippi Audubon), who doubled the festival's attendance by first inviting the banders there in 2002. "We have so many hummers migrating through--a river of birds from Canada to the Gulf Coast--that the sky is thick with them. It's pretty spectacular."
Calliope, Allen's, Costa's, Lucifer, buff-bellied, and rufous hummingbirds have all been named to the Audubon WatchList of at-risk species. Most have been singled out because small breeding and winter ranges increase their vulnerability to potential disease outbreaks, natural disasters, and habitat destruction. The rufous hummingbird, however, is of particular concern. Some of these hummers travel about 6,000 miles round-trip between the forests of central Mexico and coastal Alaska each year--measured in body lengths, it's the longest migration of any bird in North America. According to the Breeding Bird Survey, conducted annually by the U.S. Geological Survey and the Canadian Wildlife Service, from 1966 to 2002 the species has experienced a decline of 2.7 percent per year across its range.
To refuel for extended migrations, hummingbirds require stopovers in reliably nectar-rich habitat. But these areas are disappearing, not just in Mexico and Central America but throughout the United States. "As the birds move south, their habitat becomes more and more degraded. They waste a lot of time looking in flowers that aren't going to provide them with any reward in food or calories," says Grantham. Prime habitat all along their migration routes is being chewed up by everything from suburban sprawl and pesticides to invasive species and chip mills.
While banding may track the physical condition of hummers and how they are being affected by this habitat loss, homeowners needn't wait for data to prove they should take an active role in protecting them. "The average person can't really do anything to help peregrine falcons or mountain plovers, but they can do something for hummingbirds," says Sheri Williamson, author of A Field Guide to Hummingbirds of North America, who bands hummers with her husband, Tom Wood, at a station along Arizona's San Pedro River. "We underestimate the role yards and gardens have played in migration corridors," she says. A yard full of trumpet creeper and salvia and other hummingbird plants is not going to replace lost breeding areas, "but it may be able to reduce the impact of habitat destruction along migration routes."
Flowering gardens are vital, especially to ruby-throats, some of which make a nonstop, 18-hour, 500-mile-plus flight across the Gulf of Mexico. In order to complete this arduous journey, they must put on layers of fat, which their bodies burn for fuel as they fly. By hanging around a lush yard--free of pesticides, since insects can make up more than half of a hummer's diet--migrating ruby-throats gain grams in no time at all. One young female, for example, weighed 3.06 grams when Bob Sargent first trapped and banded her in mid-September at his Alabama home. Five days later, when he caught her again, she weighed a hefty 5.31 grams--well on her way to doubling her weight.
Providing sugar-water feeders could also be critical to the birds' survival, says Grantham. "We look at them as entertainment, but to hummingbirds, it may be a life-and-death struggle." Hummers are naturally solitary animals, he says, so seeing them piled up at a feeder, chasing and fighting one another, is a sign that they may really need the food.
As the first day of the Strawberry Plains celebration stretches on into the afternoon, some folks are sitting on the sun porch of the center's Civil War-era house, watching the hummers at the feeders. Others follow Kristin Lamberson, the center's horticulturist, to learn about native plants beneficial to hummingbirds. There are also demonstrations with live bats, T-shirts to buy, and guided walks on the nature trail. But almost everyone keeps circling back to see the banding.
That's just fine with Bob Sargent, who is banding at the festival, too. "We want them to hold the birds in the palms of their hands, hear their heartbeat, release them," he says. "It follows that if they get hooked on birds, soon they will learn they have to have habitat to survive. We try to make people aware as subtly as we can that they have great power as individuals. They come to these festivals to have a good time but go away with a feeling of importance."
When too many onlookers begin to congregate near the tables, Sargent picks up a female bird from Fred Bassett and moves off to the side, taking some of the people with him. "You can put seven or eight of these birds in an envelope and mail it for a first-class stamp," Sargent says, holding up the young hummer. "They weigh less than a penny."
He pauses to give the bird a taste of sugar water from a feeder. It drinks readily, lapping up the sweet liquid much like a cat laps milk. Senior citizens with camcorders, on a bus trip from Memphis, move in next to several families and a man dressed in hunting camouflage. When Sargent finishes his talk, he gently puts the hummingbird on the hand of a 10-year-old girl. "They're special birds," he tells me after the hummer flies away. "She'll never forget that."