The first known wildlife casualty of the massive oil spill threatening the US Gulf Coast was a single Northern Gannet seabird, found alive but coated in the toxic grime creeping ashore along Louisiana's coast.
That bird, recovered offshore yesterday and taken to an emergency rehabilitation centre to be cleaned up and nursed back to health, is only the tip of a potential calamity facing the region's birds, sea turtles and marine mammals.
Besides the rescued gannet, and several sperm whales seen swimming in and around the oil slick earlier, no "confirmed animal impacts" have been reported, yet, Dr. Michael Ziccardi, a veterinarian overseeing some of the wildlife rescue teams in the region, said in a telephone interview from Houma, Louisiana.
But, he added soberly: "That is not going to stay the same. We are expecting many more (casualties) in the days to come. We hope that number is not catastrophic. We're ... hoping for the best but planning for the worst."
Ziccardi is director of the Oiled Wildlife Care Network in California, a hub for the world's leading experts in capturing and caring for oil-soaked sea life.
He knows from responding to more than 60 oil spills in California that the full scope of harm to birds and other wildlife only becomes apparent once the oil washes ashore.
Oil has been gushing unchecked from a ruptured deepwater well off Louisiana, pouring into the Gulf of Mexico at a rate of up to 5,000 barrels a day since last week, and so far efforts plug the leaks have failed.
As of yesterday, the giant slick in the gulf had just begun to make landfall on barrier islands of the Mississippi River Delta off Louisiana. Ziccardi said the risk to bird species would grow as the spill progressed.
Oil impairs the insulating properties of birds' feathers, exposing them to cold and making it difficult for them to float, swim and fly. Chemicals in the petroleum also can burn their skin and irritate their eyes. They also end up ingesting the oil when they preen, damaging their digestive tracts.
Similarly, oil can be ingested by turtles and marine mammals, burn their skin and eyes and cause respiratory damage when fumes are inhaled.
How high a toll the gulf spill takes on wildlife hinges on several factors that have yet to play out, including the weather, how much of the slick can be contained and how soon crippled undersea well spewing oil can be capped.
"It's really only going to be clear in the coming days because there are a lot of unknowns," said Paul Kelway, a regional manger of the International Bird Rescue Research Center, which sent a team to Louisiana.
"All we can do is prepare these (rescue) facilities and get staff trained and be ready to help," he said in California.
The spill has come at an especially bad time for the region's bird life.
The Mississippi Flyway is a key migratory corridor that runs through the area, said Ziccardi, a professor at the University of California at Davis who wrote the US federal guidelines for rescuing wildlife in oil spills.
"There are certain songbirds and shorebirds that are going through their peak migratory period," he said. "There are other birds for which this is a nesting and egg-laying period."
The oil-coated Northern Gannet, a sea bird with striking black and white plumage that feeds by plunge-diving for fish and squid, was found in the water.
But because most birds tend to stay fairly close to land, they are most vulnerable once the oil washes ashore.
"With turtles and marine mammals, they're out in the open water, so they are at risk earlier," Ziccardi said.
Turtles may be particularly hard hit because many have just started nesting or are close to doing so in the gulf.
As for marine mammals in the region, some studies have found that dolphins and whales tend to go out of their way to avoid oil spills, while the sperm whales seen swimming around the slick suggest otherwise.
Ziccardi said, however, that the large presence of boats and planes in cleanup operations "are a wonderful deterrent" in keeping animals out of the danger zone, "so that has a double advantage for us."
Some experts have raised the possibility that prolonged difficulty in halting the oil flow from the BP-owned well could lead to an environmental disaster on the scale of the 1989 Exxon Valdez spill in Alaska, in which an estimated 250,000 seabirds perished.
But Ziccardi said that even if that happens, the mortality level for birds along the Gulf Coast may be smaller.
"We don't have the same densities of sea birds in this area as Prince William Sound," he said. "But that's not to say that if the spill continues and birds are affected, we won't have sizable losses
Ziccardi arrived in Louisiana on Thursday to manage rescue efforts for the five threatened and endangered species of sea turtles in harm's way, along with manatees, dolphins and other marine mammals. Kelway's group and another from Tri-State Bird Rescue and Research in Delaware are overseeing bird rescues.
They will be relying on teams of trained professionals and volunteers who specialize in capturing, transporting and rehabilitating animals injured by oil spills.