Six Months into Gulf Disaster: How Are Birds Doing?
Six months after the Deepwater Horizon oil rig exploded, scientists are cautiously optimistic about the state of the Gulf of Mexico’s birdlife—at least in the short-term.
Audubon Survey Results
In a report released last week, the National Audubon Society summarized results of late-September surveys conducted by a team of its scientists in 23 sections of Important Bird Areas along the Louisiana coast. Walking one-kilometer-transects within these sections—10 of which had been heavily oiled and 13 having received little to no damage—the biologists counted a total of 10,000 birds, including terns, gulls, pelicans and many species of shorebird. Of the 10,000 birds spotted, only three were oiled visibly: one willet and two American avocets.
Particularly encouraging, the team spotted large numbers of mature and juvenile brown pelicans. Large, charismatic birds removed from the endangered species list just last year, pelicans coated in oil became heartbreaking icons of the spill. Scientists worried that a combination of oil, chemical dispersants and disturbance by workers trying to clean up the mess would result in high mortality of eggs, hatchlings and fledglings. The oil rig exploded just as pelicans were beginning their annual breeding season.
Early Migrants Thriving
In more good news, Tom Moorman, director of conservation planning for the southern region of Ducks Unlimited, says that a collaboration between his organization, federal agencies and gulf coast farmers to create food-rich, uncontaminated habitat for migratory birds is going well so far. In Louisiana, landowners working with the project have made 75,780 acres available to the group.
“Where these lands have been flooded, the response has been phenomenal,” reports Moorman, who says thousands of waterfowl including blue-winged teal, mottled ducks, black-bellied whistling ducks and pintails have flocked to these habitats. “Shorebirds like long-billed dowitchers, semi-palmated sandpipers and least sandpipers also are abundant.”
But Oil Remains in Habitat
But birds, both resident and migratory, are not out of the woods. Along with abundant birdlife, the Audubon teams observed widespread evidence of oil—surface oil, tar balls, seepage from pockets just under the sand as well as oil in the water column—in nine out of ten sections previously hit heavily by the spill.
At an October 14th press conference sponsored by the Gulf Restoration Network, Clint Guidry of the Louisiana Shrimp Association reported that just a few days earlier “a large amount of oil flowed into Barataria Bay, but this was not reported in the press.” Guidry added that similar incidents occur “once or twice a week.”
Most Migrants Have Not Arrived
According to Moorman, “most of the waterfowl have yet to arrive.” Species expected in late October include gadwalls, wigeon and some green-wing teal, along with the first flocks of snow and white-fronted geese. November is peak arrival time for redheads, surf scoters, buffleheads, ruddy ducks, greater scaup, long-tailed ducks red-breasted mergansers, lesser scaup and loons.
Speaking at a recent meeting sponsored by the Smithsonian Migratory Bird Center and Cornell Lab of Ornithology, Ken Rosenberg, director of conservation science for the lab, said: “Our biggest concern are the rafts of loons, lesser scaup and other birds that will be feeding offshore and diving into water that still contains oil and chemical dispersants,”
Long-term Damages Unknown—and Worrisome
Longer term effects on both migrant and resident birds are even more worrisome. “Even if the birds look healthy now, we can’t begin to predict all the health and reproductive effects that could show up later,” says Melanie Driscoll, Audubon’s Louisiana bird conservation director and a member of the group’s survey team. Many birds that do not appear to have oil on their bodies probably came in contact with or even ingested it over the past six months. Even harder to predict are long-term effects on the gulf’s food webs, which are critical to bird reproduction and survival.
“Looking back at what we knew six months after the Exxon Valdez disaster in Alaska illustrates the danger of too quickly drawing conclusions about the full impacts of the Gulf oil disaster,” says NWF Senior Scientist Doug Inkley. Six months after that spill, for example, Prince William Sound’s herring stocks “seemed like they’d pull through,” Inkley says. “It wasn’t until the fourth year that herring stocks collapsed due to a delayed population effect of the oil, devastating the people and wildlife that depended on them. Today, more than two decades later, this once-vital fish still hasn’t recovered.”