Oil Spill Wildlife Spotlight: Gulls and Terns

Royal tern (Photo: Bill Stripling, courtesy of National Audubon Society)
On so many beaches and shores, gulls and terns are as ubiquitous as the sand and water. The Gulf Coast is no exception, where laughing gulls, and least, Forster’s, sandwich, royal and Caspian terns could all be at risk from the devastation caused by the month-old Deepwater Horizon spill.
Some gulls are particularly vulnerable to oil-covered water because of how they feed. Laughing gulls, for example—a species that, much like the reddish egret, once was threatened by the feather trade—seek out fish and crustaceans where the water meets dry land and from atop the ocean’s surface, occasionally dipping their heads below to snatch up food. Along the Gulf Coast, from the southern U.S. down to the Yucatan Peninsula, these gulls have already started their breeding season, an occasion that brings as many as 25,000 nesting pairs to a single colony. That means a lot of the species in one place, which, despite an 800,000-count population, could still be damaging.
“They’re likely to be some of the birds brought in as oiled,” Greg Butcher, National Audubon’s director of bird conservation, told reporter Michael Lowe about the laughing gulls. Butcher’s also concerned about several tern species—more so than other coastal species—because they forage on the open water where they’ll easily come in contact with the oil. “There’s no way to put booms where they’re looking for food,” he said.  

Laughing gull (Photo: Bill Stripling, courtesy of National Audubon Society)
Oil contamination will be particularly problematic once tern chicks hatch this spring/summer, especially for larger tern species that typically have just one per year, according to Winnie Burkett, Houston Audubon’s sanctuary manager.
Because many tern species are what Burkett calls attentive parents, if oil covers their wings but they can still fly, they’ll return to their babies, potentially contaminating the nests and causing unintentional harm. “They also regurgitate food,” says Iliana Peña, director of conservation and education for Audubon Texas. “If they’re ingesting fish affected by the oil or dispersant, they’re passing that on in digested form to the chicks.” What’s more, to stay cool in warm temperatures, tern chicks head to the water pretty soon after they hatch. Caspian tern chicks, for instance, leave the nest in just a few days.
Burkett says the timing of the spill is horrendous. All of these species “have to get a lot more food this time of year, when they’re breeding and when they’re feeding chicks.” Not to mention that like laughing gulls, terns are much more concentrated in nesting spots, making a hit to those areas even more devastating.  

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