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Before the BP oil spill, this shrubby island along the Louisiana coast was a lush green rookery where noisy brown pelicans and other birds clamored. Two years later, the island is smaller and ragged, full of dead black mangrove stumps and muddy patches.

Cat Island was one of the first places to be hit by thick mats of oil coming from 50 miles away in the Gulf of Mexico. Crews hired by BP raced to try to protect the island with boom, skims and dispersant, but a lot of the effort was futile. Some of the most iconic images from spill — confused, struggling pelicans covered in oil — were seen near these parts.

There are fewer pelicans now on the island, which is washing away, a process perhaps exacerbated by the oil spill.

"It's eroding like sugar in hot coffee," said P.J. Hahn, coastal zone manager for Plaquemines Parish, as he looked at Cat Island from a boat on a recent morning.

Hahn studied the island and shook his head. He estimated in the past two years the rookery has shrunk from 4 acres to less than 1.

Cat Island is one of several remote mangrove rookeries at the edge of Barataria Bay and the Gulf of Mexico where a variety of birds nest in safety, far away from predators like raccoons and coyotes that can't swim in from larger nearby islands and marshlands.

This makes the mangrove islands vital habitat for a host of sea birds like the brown pelican, which had been taken off the list of endangered species shortly before the BP-leased rig Deepwater Horizon exploded April 20, 2010, and the nation's worst offshore oil disaster began. Pelicans remain abundant despite the spill, and there's no talk of putting the bird back on the endangered species list.

Beyond these isles, low-lying coastal Louisiana is experiencing some of the fastest rates of land loss and erosion in the world. Since the 1930s, Louisiana has lost about 1,900 square miles of land due to a range of causes, from oil drilling to erecting levees on the Mississippi River.

Richard DeMay, the senior scientist and a veteran birder with the Barataria-Terrebonne National Estuary Program, said it was difficult to gauge just how much the oil spill has increased the erosion.

"We can't tease out what is natural shoreline erosion from year to year and what was caused by the oil spill," he said. "We do know that there are less birds on those island than there have been because those islands are shrinking."

There are plans to try to rebuild Cat Island and four nearby islands.

Hahn said the parish has about $1.3 million to spend on Cat Island. The plan is to place concrete barriers around the island and pump in mud to build it back. DeMay said he was working on plans for four nearby islands owned by the Apache Corp., an oil and gas company. He said about $1.5 million has been donated for that work, with $1 million coming from Shell, the oil giant.

"For these islands, it's desperate times," DeMay said. "If we don't do anything soon, we will lose them."