Declining Animal Migration and Climate Change in New England
written by: ESH•edited by: Sarah Malburg•updated: 1/19/2011
Even many residents of New England don't know that their region lies along epic travel routes of species as diverse as monarch butterflies and North Atlantic right whales. Learn more about New England animal migrations, some of which are declining, and possible effects of climate change.
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New England Animal Migrations
Despite the inherent drama of long-distance animal migration—hundreds or thousands of animals trekking across huge expanses of land, air and water between seasonal ranges—can be surprisingly inconspicuous to humans. Even in a well-populated place like New England, throngs of traveling birds may pass mostly unnoticed far overhead of bustling towns and cities. For those in the know, however, and with a watchful eye, the New England region can be an exciting place in the spring and autumn, with everything from butterflies to baleen whales on the move. The potential effects of climate change on such animal migrations are poorly understood, but the more observers keep track of their annual rounds, the more light may be shed on this complicated issue.
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North Atlantic Right Whale
One of the most imperiled and dramatic migrations in the US takes place partly in offshore New England: the annual trek of the North Atlantic right whale between calving and feeding grounds. The whales winter and give birth off the coasts of Georgia and Florida, then head north in the spring for feeding grounds off New England and Nova Scotia. Right whales are so-called because their slow-moving, coastal habits made them the “right" target for whalers. Slow to recover from overexploitation, North Atlantic right whales now face troubles associated with their migration path hosting increasingly busy shipping traffic as well as offshore oil and gas extraction. There may be no more than 300 or 350 right whales left in the North Atlantic, making them one of the most threatened cetacean populations in the world. Recent conservation efforts aimed at bolstering this declining migration have tackled reducing ship speeds, adjusting shipping routes and managing against whale entanglement in fishing lines.
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The North Atlantic population of humpback whales also journeys along the New England coast in seasonal migration from Caribbean wintering waters to more northerly feeding areas. Compared with the squat, barnacle-ridden right whales, humpbacks are sleeker, with slender snouts; their enormous flippers are their defining feature. Other baleen whales with more poorly understood seasonal movements that may be encountered off the New England coast include sei, minke and finbacks.
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New England lies along a major migration route for birds of prey in eastern North America. Migrating raptors seek out the updrafts produced by the region’s belts of parallel ridges and are also funneled along the Atlantic coast. At sites like Hawk Mountain in Pennsylvania and the Kittatinny-Shawangunk Ridge and Corridor between New York and Pennsylvania, birders regularly congregate in spring and especially autumn to view everything from American kestrels to golden and bald eagles on the wing southward. Certain species, like broad-winged hawks and turkey vultures, may assemble in massive, swirling “kettles"—great aggregations of birds riding a thermal or updraft in spectacular fashion.
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Other Winged Migrants
In addition to the concentrations of raptors, many songbirds and shorebirds migrate through New England, many shunted along the coast. A number of species, like the blackpoll warbler, actually head seaward off New England capes and travel thousands of miles over the ocean to the Caribbean and South America. Similarly, monarch butterflies—which cannot survive the fierce winters of the northern United States—migrate southward along the New England coast, as well as points inland, to winter in Mexican highlands.
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It is possible that ongoing climate changes may trigger declining animal migrations. There is some evidence that a warming climate may encourage birds that have historically migrated to remain year-round in a given region. A 2006 assessment by the World Wildlife Fund, titled “Bird Species and Climate Change: Global Status Report", suggested that, worldwide, long-distance migrating birds may be negatively affected by a rapidly shifting climate because food sources they rely upon in one destination or another may become available earlier than they tend to arrive. As shifting food sources are among the chief impetuses for animal migration, climatic shifts in their distribution may significantly change the routes and nature of these epic journeys.