The Gulf of Mexico is one of the country's most important habitats for birds , with more than 300 species living in or passing through it. There are 34 federally-protected species that call the Gulf home.
When oil polluted the fragile ecosystem after the BP oil rig explosion a year ago, many experts feared the wildlife might not fully recover.
But on this first anniversary, there's good news and not so good news, reports CBS News correspondent and "Early Show" resident veterinarian Dr. Debbye Turner Bell.
For instance: More than 600 oil pelicans were cleaned and released out of harm's way, some in Georgia, migrated south for the winter. Experts wondered what would become of them.
Tim Keyes, a biologist from the Georgia Department of Natural Resources, says he had no idea whether they'd survive the winter.
Keyes eagerly awaited and found a red band around the pelican's leg, a mark of an oil spill survivor.
"The fact they've made it this far, survived a winter, which is typically a stressful time for pelicans, and made it back here, migrating back north, are all good signs," Keyes says.
A glimmer of good news after months of bad reports -- more than 8,000 birds, 1,000 sea turtles and 100 dolphins and whales were found visibly oiled or dead in the months after the spill. Today, the pelicans' original home in Louisiana is a very different sight. Air cannons fill the air in Baritaria Bay to keep birds away from marshes still soaked in oil. That's state biologist Todd Baker's territory.
Doesn't this drive you crazy? About a year later, this still looks ... bad? Turner Bell asked.
"Well it's unacceptable, that a year later, we're still looking at mobile oil, sheen, still seeing crabs and small little animals crawling through this mess," Baker says.In numbers, birds top the list of the dead, but experts believe endangered sea turtles may have been hit the hardest.
"They looked like they had been dipped in rich chocolate mousse," says Dr. Cara Field, associate veterinarian at the Audubon Nature Institute.
It has taken ten months for the 30 rescued sea turtles to heal from infections and broken bones, cared for at the Audubon Nature Institute in New Orleans. They're finally ready to be released.
But experts are questioning the health of the Gulf after an unusually high spike in dolphin strandings along the coast. Since January, more than 170 have been found dead, nearly half of them babies.
Is it suspicious, Turner asked that, in the first calving season after this huge oil spill, you have the high mortality?
"In the public's mind, the connection is there, and that is why it's frustrating that we don't have the results that we should have to be able to mitigate these issues or answer these tough questions," says Dr. Moby Solangi, executive director at the Institute for Marine Mammal Studies.
Cleanup in Baritaria Bay will take years, and it may be longer before we know just how much damage was done to the Gulf's vital ecosystem.
Turner Bell came upon an injured frigate bird just rescued with oil on it.
"Whenever they become impaired, they seek refuge on the first piece of land to get out of the water. The bird found a tarball field," Keyes added.
The reality, says Bell, is we may never really know the true death toll. Some experts say could be 50 times higher than what's reported. However, experts believe the Gulf can recover.