Home - Songbird Superhighway – Spring 2011
The amalgamation of the Network’s research is expected to offer a clear picture of how migratory songbirds and other migratory species such as waterfowl, seabirds and shorebirds, are using the Gulf of Maine. Evolutionary changes in birds likely won’t keep up with human alterations to landscape, but at least scientists will know what species are flying through the area, how the birds are using different areas of the gulf, and how their numbers may be changing in the face of environmental challenges. Holberton’s own research over the years has focused on the Blackpoll warbler, a boreal forest breeding bird that undertakes one of the longest non-stop migrations in North America. But in 2005, a report by the Alaska Department of Fish and Game claimed Blackpoll warbler populations have declined as much as 90 percent in Alaska and western Canada.
How does the changing climate have the potential to affect the Blackpoll warbler populations – and provide an example of why the Network’s research is so critical? In years when there are a lot of hurricanes along the eastern North Atlantic where these warblers fly non-stop from the eastern U.S. to winter throughout the Amazon River basin, the warblers suffer devastating losses as they migrate during hurricane season.
“In a 40-year period, say, you run those chances,” Holberton says. “But what do we heard every year? Hurricane frequency and intensity have increased over the few decades and they’re going to increase more. Studies by Manomet Bird Observatory researchers have show a strong correlation between storm frequency and decline in Blackpoll numbers over the last three or four decades. The Blackpolls can’t evolve fast enough to adjust their migratory behavior to avoid that. It’s easy to get complacent with a species that’s always been considered so common and overlooked. The population loss hasn’t even made the headlines but it’s one that could slip very quickly.”
Climate change isn’t the only potential threat to birds migrating in the Gulf of Maine, although it’s one of the biggest. Land development along the coastline could change how birds use their stopover sites; the gulf could see more areas with fire escape capabilities, for example, while there are fewer five-star hotel zones, a situation that could not sustain successful migrations of millions of birds annually.
More and more commercial developers and communities are looking to coastal or near-shore areas for sources of wind energy. Deep-water wind platforms are in the experimental stages, but may pose the least risk to birds and also bats. Holberton, her team at UMaine, and the rest of the Network researchers hope their findings will be used to support responsible development in and around the Gulf of Maine, especially now that researchers such as Leppold have shown the region is a superhighway for songbirds and other species.
“Maine desperately needs a comprehensive, long-term plan for coastal and offshore development that takes into account not only our region but those north and south of it,” Holberton says. “These birds that travel well beyond the Gulf of Maine are very good at what they do, but it might not take much more than one thing, such as loss of critical migratory habitat in addition to loss of wintering and breeding areas, to push them over a threshold at which they can no longer sustain their populations. That’s the issue.”