Two in the Net: How Birders Are Changing The World, One Bird at a Time

by Colleen Cassidy, a recent graduate of Cornell

David Holmes wears his binoculars on a pair of suspenders, speaks in acronyms, and can spot a leaf-colored bird in a tree ten feet away. Holmes holds the rank of Master Bander and works at the Migratory Bird Banding Station on Appledore Island in the Gulf of Maine. His day starts at dawn, when birds are most active. "They wake up and they need to put fuel in the tank," he explains.

He and his team of volunteers catch the birds in mist-nets, which resemble saggy volleyball nets. The nets’ filmy weave, combined with the low dawn light, make them almost invisible to birds, and to people. "Catching yourself is counterproductive," says Lindsay Herlihy, a bander-in-training, "but not always unavoidable."

The first catch of the day is an American redstart, a member of the warbler family. This individual is young, with yellow side spots and a gray back, instead of the adults’ bold black and orange patterning. Holmes gently untangles the bird from the net and brings it back to the lab in a small paper bag.

He rattles off a four-letter acronym and a string of numbers, which represent the bird’s species, and which net it came from. "The first thing we do is to put a band on, so if he escapes and we catch him again, we can get the rest of his information." Tipping the bird upside down, he deftly maneuvers a pair of pliers around the bird’s leg and attaches an aluminum band. The bird cheeps and flutters at the humiliation of his belly-up position, but Holmes has a firm grip. He reads off the band’s number to Herlihy – another string of numbers, each one unique. "It’s like giving the bird a name," Herlihy explains.

Holmes and Herlihy are unlikely to encounter this bird again once they release it. Banded birds, even small ones like this redstart, contain a wealth of useful information. Using the data collected by Holmes and his team, as well as new information obtained by tracking individual birds wearing data recorders, scientists are building a clearer picture of the routes migratory birds use to travel. This picture will have consequences for everyone from airline pilots to wind farmers.

Using the island as a refueling station, migrating birds gorge on the abundant insects and late-summer fruits. The birds store fat that they will call upon as they journey south to their wintering grounds. "With a good fat load, these birds can fly one hundred hours non-stop," says Holmes. "They can cover incredible distances."

Millions of other songbirds will join the redstart on his journey, streaming toward the southern hemisphere in a cloud of feathers and flutters. But exactly how the birds get from Maine to Managua is a puzzle scientists are just beginning to crack.

Using dime-sized "bird backpacks," scientists have recently been able to follow individual birds from the beginning to the end of their migration. Bridget J. M. Stutchbury, a biologist at York University in Toronto, fitted 34 songbirds with the backpacks – packages of equipment designed to detect where the bird was in relation to the sun. Once Stutchbury retrieves the backpacks from the birds, she will use this information to determine how fast the bird was flying, where it stopped to rest and for how long, and exactly what route an individual bird took. This is the kind of information the bird banders had hoped to get by recapturing banded birds "but we almost never catch the other station’s banded birds." David Holmes says.

Holmes is enthusiastic about using Stutchbury’s data to learn about the fate of migrating birds. "The elephant in the room, when you talk birds, is collisions." Collisions between birds and planes happen thousands of times each year – twenty will occur in the time it takes to read this sentence.

According the Bird Strike Committee USA, in 2007 alone over 12,000 bird strikes caused $650 million in damages to aircraft. These numbers were gruesomely brought to life in January 2009, when U.S Airways Flight 1549 made an emergency landing in the Hudson River after two birds struck the engines shortly after take-off. The United States Department of Defense is responsible for mapping airline routes, and knowing the exact routes that migrating birds use will allow pilots to avoid those routes, and prevent similar incidents from occurring.

Migrating birds also face hazards from the green energy movement. More and more countries have been turning to wind power as an alternative to gas and oil for producing electricity. As a result, giant banks of wind turbines have been sprouting off coastlines. Placing the turbines over water puts them in the path of the strongest winds, and also in the path of many migrating birds.

The State of Maine is hoping to install a large bank of turbines just off its coast, but wants to know how those turbines would affect migrating birds. Appledore Island, six miles off the Maine coast, recently acquired a wind turbine in the hopes of reducing the island’s reliance on costly generator power. The State of Maine asked Holmes and his banding team to monitor the turbine for bird collisions, so every morning Holmes walks around the turbine, checking for the bodies of songbirds. "In five seasons of doing this, we have not found a single dead bird," Holmes reports. "except the ones put there on purpose."

Holmes cautions against placing too much weight on their results. "We’re looking at a small turbine that’s on a small island, so you have to be careful applying what we see here to a situation with many, large turbines over water."

Nevertheless, Holmes remains upbeat about the future of wind farming. "There’s an experiment in Mexico right now, looking at the migrating raptors." Each year, thousands of birds of prey fly down the western side of Mexico and cross over to the Gulf of Mexico. "They were seeing 300,000 birds in one day," he says, "it’s been called, ‘the river of raptors.’" The World Bank would like to provide funding to put large banks of wind turbines along the birds’ migration route, "but they have one requirement: whoever ends up running the turbines will have to shut them down completely during migration season."


Holmes is thrilled that non-birders have taken an interest in birds. "We’re finding out pieces of how the world works," he says. And those pieces are rerouting plane and shaping the clean energy movement. Holmes has finished banding and measuring the redstart, and carries it outside for release. The bird leaves his hand, its duty to science finished, its own small piece of the puzzle now recorded and available for future use.