We're standing near the lakeshore at Kaiser-Manitou Beach Banding Station, roughly 15 miles west of Rochester. In front of me, Dr. John Waud, professor of environmental science at Rochester Institute of Technology, gently extricates a bird - a brown, spotted thrush called a veery - from the fibers of a tall mist net (which looks something like a volleyball net with fine, almost invisible mesh). The veery in Waud's hand, along with scores of other birds, has flown across Lake Ontario in the dark of night and was captured at the banding station, which is run by a cadre of volunteers associated with the nonprofit Braddock Bay Bird Observatory.
Volunteers at Braddock Bay use mist nets to monitor the passage of songbirds during spring and fall migrations. In the last decade alone, they have tagged 98,000 birds from approximately 130 species. They place a tiny band around each bird's leg, record its physical condition, and then release it. When banded birds are recaptured - either by this crew or by another banding team in its flight zone - a picture of bird migration starts to develop.
Elizabeth "Betsy" Brooks, long-time bander and co-founder of the Braddock Bay Observatory in 1985, estimates that she has banded more than 80,000 birds in her lifetime. After handling that many birds and tracking their movements, she knows a little something about the miracle of migration. She especially knows the challenges faced by a tiny songbird as it crosses Lake Ontario during its migrational sojourn.
"On October mornings," she says, "I've seen scores of ruby-crowned kinglets dripping off the tree limbs and blanketing the ground, weak and exhausted having just been caught over the lake in a squall."
Crossing Lake Ontario is just the first obstacle for most birds. For many species, migration is a transcontinental, transoceanic event that stretches down to South America. To survive this trek, birds must find safe places all along land routes where they can rest and bulk up on a high-energy, high-protein diet of berries and insects. Ecologists call these safe zones "migratory stopovers," and studies show that in North America's increasingly fragmented landscape, a shortage of stopover habitat is contributing to population declines in migrating landbirds.
In lakefront communities like those surrounding Rochester, a shortage of stopover habitat can be especially challenging for birds migrating from Alaska and Canada. As a result, the Central and Western New York chapter of The Nature Conservancy has teamed up with a group of scientists for a study to identify local migratory stopover sites in the region, with the goal of eventually safeguarding the sites and the birds that depend on them.
The 5 billion-bird marchThis fall, more than 5 billion birds will migrate across North America, each traveling a semi-predictable flight path between its breeding and wintering grounds, each requiring quality stopover sites between flights. Despite how masterfully engineered these tiny flight machines are for migration, studies show that some species, especially the fast-declining group of neotropical migrants that winter from Mexico to South America, can experience up to 85 percent mortality during their annual treks. Considering that a migratory bird spends nearly one-third of its year traveling between its breeding and wintering grounds, there's ample opportunity for danger.
Most birds migrate under the cover of night using tailwinds to boost their flight. Navigating by the stars and by the earth's magnetic field, birds dodge an incredible number of obstacles. If not eaten by a hungry hawk or owl, they may fall victim to plate-glass widows, cell-phone towers, or turbines on wind farms.
After flying hundreds of miles in a single night, lean and weary birds seek refuge, sometimes desperately, in woodlots, backyards, orchards, and wetlands where they can rest and refuel for the next leg of their journey. This hopscotch nature of migration makes birds highly dependent on quality stopovers that need to be strung out in regular occurrence along routes that cross thousands of miles.
Astonishingly, many birds return to the same backyards repeatedly over their life spans, a navigational phenomenon called site fidelity. "A bird's ability to fly hundreds or thousands of miles only to find the exact same feeder over and over again just blows my mind," says Betsy Brooks.
Clearly, then, the key to conserving bird populations is to protect habitat, not only where they nest each spring and where they hunker down in winter, but in the multitude of migratory stopovers along their flyways.
Rochester's migration sceneThe Rochester region - indeed, most of western New York - plays an important role in bird migration for two reasons. First, we are located in the Atlantic Flyway, one of only four major migration routes in North America. The Atlantic flyway cuts a broad swath across Canada, funnels through the Great Lakes, hugs the Atlantic shore and continues toward the Gulf of Mexico and beyond.
Our location on the southern rim of Lake Ontario is also critical. "Lake Ontario presents a significant milestone to migrating birds," says David Klein, senior field representative at The Nature Conservancy Central & Western New York. "Birds tend to ‘pool up' on either side of the lake just prior to, and after, crossing."
In fact, avid bird watchers depend on this fact. Bob Spahn, who has birded the Rochester area for more than 50 years, combs small woodlots along the lakeshore during spring and fall where, he says, "birds tend to pass in clumps and bursts."
Birders refer to this as "migrant fall-out," and find reliably good numbers and kinds of birds in lakeside habitats such as Island Cottage Woods Preserve, Durand-Eastman Park, and Hamlin Beach State Park. Some sites further inland, such as Cobbs Hill Park and Letchworth State Park, are also migrant hotspots, especially during spring
Using his eyes and well trained ears, Spahn ticks off every bird he observes onto a card or neat checklist; his New York state bird total hovers near 386 species, out of a possible 470. Spahn finds it more challenging to identify songbirds in fall, since at that point birds no longer sing to attract mates, and their colorful breeding plumage has molted to a winter drab, allowing the birds to elude predators and focus their energies on flying.
When birds arrive on the southern lakeshore, particularly after storms, they are fatigued and hungry. Therefore, undeveloped areas on the shoreline of Lake Ontario, and to an unknown degree farther inland, are critical pit stops for migrants.
But what makes a quality stopover site? How far inland do they occur? And how might these stopovers, which occur on patchwork of public and private lands, be protected?
Large, expansive wetland complexes, such as Montezuma National Wildlife Refuge and the 17-mile stretch along the eastern shore of Lake Ontario, are well known stopovers for migrating waterfowl and shorebirds. They have been protected accordingly.
But studies show that a small, isolated woodlot in the middle of a farm field or a small patch of woods in the city (think Rochester's Washington Grove, or Central Park in New York City) can be just as vital to migrating songbirds - such as robins, wrens, warblers, thrushes, kinglets, and orioles - as long as they have abundant cover, insects and fruiting shrubs or trees.
Surveying the local bird sceneBut how small is too small? How isolated is too isolated? To address these questions, staff from The Nature Conservancy has teamed up with scientists from Audubon New York, New York State Department of Transportation, and five area universities (both Klein and Waud are on this team). This study, funded by the New York Department of Environmental Conservation, is part of a broader Nature Conservancy effort to identify and preserve important wildlife habitats in the Great Lakes' coastal zones.
After examining the scientific literature, the team identified three of the most important characteristics for stopover sites and developed a predictive model using remote-sensing and GIS (Geographical Information Systems) technology. The team is testing its model on 21 study plots located on a mixture of private and public land from Aurora to Syracuse.
During the next several migration cycles, experienced volunteer birders - including Spahn and others who can identify approximately 90 percent of birds by sight and sound - will walk these study plots and tally each bird they observe. Birders will submit their counts to team leaders, who will analyze the data and enter them into eBird, a continent-wide database of birds developed by Audubon and the Cornell Lab of Ornithology.
If predictions are on the mark, volunteers will observe a high number of migrant songbirds in plots that are closer to the lakeshore, feature woody cover within 5 kilometers of the site, and retain high habitat diversity. With this confirmation, scientists would able to use remote-sensing technology, rather than labor-intensive field studies, to analyze where quality stopovers occur.
This three-year study will result in a map of regional stopover sites and a set of guidelines that can be used by landowners, governments, and land trusts to help them make informed decisions on how to protect migratory stopovers. The study will also help organizations prioritize spending on land conservation projects that protect bird populations.
"Migration presents an exciting but fragile time in a bird's life," says Betsy Brooks. "One wrong move and a hawk has it in its talons. One sudden sleet storm over Lake Ontario and a migrating kinglet drops exhausted and drowns. A young gray catbird banded here in Rochester can be found dead a week later on an oil platform in the Gulf of Mexico..."
http://www.rochester-citynews.com/news/articles/2009/09/OUTDOORS-A-bird-in-the-hand/Long article....continues here
