Seabirds Warn of Ocean Change
What can 30 years of research and monitoring on Maine seabirds teach us? That the marine environment is changing fast. That ocean birds may be failing to adapt. That the scope of few marine threats – from ocean warming and offshore energy development to competition from commercial fisheries − could have been foreseen when Maine Coastal Islands National Wildlife Refuge staff began studying the birds in the early ‘80s.
The refuge, made up of more than 50 islands in the Gulf of Maine, uses data from research and monitoring to manage Maine seabird colonies and try to stem the birds’ decline.
Arctic Tern and the World’s Longest Migration
Similar declines reported by the Netherlands and Iceland suggest that more than a local factor is to blame. Some researchers suspect climate change is disrupting the food chain in the birds’ wintering grounds. “So it might be the birds can’t find enough food to rebuild their body stores and regain the energy they need to fly from Antarctica all the way back to the coast of Maine in good enough shape to start breeding again,” says Welch.
Great Shearwaters and Wind Farms in the Gulf of Maine
Bird-tracking devices may also help researchers unravel a mystery: why some Maine seabirds can’t find enough fish to feed their chicks. Arctic terns forage for herring and other small fish at the water surface; unlike puffins and razorbills, they can’t dive for fish. Machias Seal Island once hosted the largest tern colony in the Gulf of Maine. But in 2007, a fish shortage led 3,500 tern pairs to abandon their nests. “They haven’t raised any chicks since,” says Welch.
Desperate to Feed Their Chicks
While the problem appears worst for Arctic and roseate terns, puffins and razorbills are also affected. At most colonies, puffins are generally able to still produce chicks, but often those chicks are smaller and weigh less, says Welch. “So we don’t know: Are those birds going to survive once they leave the colony? Will they be able to return when they are five to six years old and breed?”
Marine productivity levels, water currents and water temperature all influence the distribution of fish. Increased Arctic ice melt could also affect water chemistry and the location of fish. “It’s not an easy problem,” says Welch.
New Tracking Technology
But interpretation of bird movement patterns, population changes and productivity rates all rely heavily on visual data painstakingly collected over the past 30 years. It’s not glamorous work. Each summer, seasonal technicians live on the seabird colonies and monitor the seabirds. Peering through binoculars, they document how many pairs return to the colony, how many eggs are laid, how many of those eggs hatch, how often chicks are fed, and which species of fish are brought to the chicks. Researchers compare notes with conservation partners in the United States and Canada who are also monitoring seabird colonies throughout the Gulf of Maine.
“Having a long-term monitoring effort has been critical to our understanding of changes in productivity and seabird diet,” says Welch. “For example, with the Arctic terns, we had 25 years of population growth. Now we have five years of population decline. Our management actions haven’t changed. Our predator control actions haven’t’ changed. So we know something else has changed. This large collaborative data collection effort gives us a much better understanding of the system.”
For its seabird research, the Maine Coastal Islands National Wildlife Refuge received a Rachel Carson Award for Scientific Excellence from the U.S. Fish and Wildlife Service for 2012.