BURAS, La. -- The large, oily pelican struggles as one man in a blue full-body protective suit hugs the bird to his chest and holds its long beak and another examines it and helps lower it into a metal tub.

Nearby, groups of two or three workers examine birds, spray them down or scrub them with a toothbrush.

The assembly-line efficiency that moves a bird quickly through this major cleaning process would be impressive if it weren't so heartbreaking. The technique has been honed through decades of work rehabilitating wildlife from oil spill after oil spill around the globe.

The Fort Jackson Wildlife Rehabilitation Center near Venice, La., has taken in about 600 live birds so far. The center has treated egrets, herons and laughing gulls, among other species.

Birds are cleaned quickly through an assembly line-like process. Photo by Noelle Straub.

The pelicans are the lucky ones. Because of their size and strength and their social natures, they fare better through this tough process. It is much harder on the smaller birds like terns, which are shy and get more stressed, said Jay Holcomb, director of the International Bird Rescue Research Center.

He estimated a survival rate of more than 80 percent for the birds at the center.

Most of the birds arriving here seem to have oil only on their feathers and have not ingested it, said Rebecca Dunne of Tri-State Bird Rescue and Research. "These birds are basically healthy birds with some oil on them," she said.

But it is harder to gauge internal damage. "There's always the risk of kidney and liver damage, reproductive damage," Holcomb said.

Once the birds are released back into the wild, it is difficult to track them and determine long-term effects, he added.

A few weeks ago the center was taking in 50 to 100 birds a day, but as the oil slick has moved toward the east, that has dropped to 20 to 30 per day, Dunne said.

Oiled birds are held in large wooden crates before they are cleaned at the Fort Jackson Wildlife Rehabilitation Center near Venice, La. Photo by Noelle Straub.

When a bird first arrives here it is given a physical exam to assess its condition. The workers then pluck a feather from each bird and take a photo, which are given to the Fish and Wildlife Service law enforcement as evidence.

The feather is used to analyze the oil's chemical fingerprint and prove whether it came from the Deepwater Horizon spill.

The birds spend a day or two in one of about 20 large wooden crates covered with netting that fill the floor of the warehouse-like building. That allows the birds some time to calm down after the trauma of being captured and taken out of their habitat.

Release on Atlantic Coast

Groups of about a dozen dark-brown coated pelicans huddle together in each cage, a bowl of fish available for lunch.

Once they are strong enough, the birds head to the cleaning area. They are pretreated with a product to loosen the oil, then hosed down with a garden sprayer filled with Dawn dish detergent. Use of the sprayer is fairly new and cuts down the time the birds must be handled, lessening their stress levels, Holcomb said.

The birds are then washed by hand in a bath with water at their body temperature, 104 degrees, rinsed carefully and put in a separate small room under blow dryers. Some of the most oiled birds have to go through the process more than once.

Once sufficiently clean, the birds are moved to an outdoor aviary with pools of water where "their jobs are to swim, eat and preen so they can get healthy and be released," Dunne said.

The birds have another physical to ensure they meet the weight, blood values and other requirements to be released.

The aim is for the birds to be at the center a total of 10 days maximum but ideally just five to seven days, Dunne said.

The recovered birds are flown by helicopter to the release site, currently Merritt Island National Wildlife Refuge near NASA's John F. Kennedy Space Center in Florida. But the cleanup groups are encouraging the Fish and Wildlife Service instead to release them further up the East Coast where they have less chance of returning to oily areas, Holcomb said.

2 nonprofits doing cleanups

The service captures the oiled animals and decides where to release them, but federal agencies do not clean wildlife.

The company responsible for the spill, BP PLC, contracted two nonprofit groups for the job, the California-based International Bird Rescue Research Center and the Delaware-based Tri-State Bird Rescue and Research.

Once sufficiently clean, the birds are moved to an outdoor aviary with pools of water where they can "swim, eat and preen" before being released. Photo by Noelle Straub.

The groups work under permit from the Fish and Wildlife Service, which has approved their protocols, Holcomb said.

A local group, the Louisiana State Animal Rescue Team, which got up and running during Hurricane Katrina in 2005, also has been working at the Fort Jackson center. That group has been included so local residents have a chance to be involved in the wildlife recovery effort, Holcomb said.

The two nonprofits have 30 staff members working at the center, and the rescue team has another 20. There are not any true volunteers working there, Holcomb said.

The companies specialize in oiled animal rescue, traveling the world to clean wildlife wherever a spill happens. Holcomb cleaned wildlife after the 1989 Exxon Valdez spill in Alaska and helped treat tens of thousands of penguins after a spill in South Africa.

But the Gulf disaster is different.

"None of us," he said, "have ever experienced an oil spill this ongoing."