This arc of barrier islands off the Louisiana coast is only a hint of what it looked like 100 years ago when President Theodore Roosevelt declared it a bird reservation.

As the nation's second-oldest refuge, the Breton National Wildlife Refuge has been battered by hurricanes and human activities. In mid-September Hurricane Ivan's storm surge inundated the islands, leaving many of them underwater.

The refuge, made up of the Chandeleur and Breton islands, will celebrate its 100th birthday Monday. The milestone will be marked by several exhibits and a symposium in New Orleans.

The islands show up on most maps as an arc of long, skinny strips in the waters east of New Orleans and south of Biloxi, Miss.

A lot has changed on the islands in the past century. Once there was a fishing settlement with a school and homes. It was destroyed by a powerful hurricane in 1915. At one time there were trees, and people farmed there.

But since the late 1800s, the islands have shrunk, losing 37 percent to 39 percent of their surface. To offset the erosion, marsh grass has been planted on several of the islands.

"My first trips out there were in the '70s with my dad, and they were islands at that point, but they have progressively gotten smaller and smaller," said Carlton Dufrechou, executive director of the Lake Pontchartrain Basin Foundation. "The storms in the last decade seem to have done a number on them, and I'm afraid we're beginning to see the remnants of the Chandeleur Islands."

Roosevelt declared it a reservation because the islands' brown pelican populations were being plundered by plume hunters looking for fancy hat feathers. Raids by plume hunters had prompted Roosevelt a year before to declare Pelican Island in Florida a refuge, the first of what would become the national wildlife refuge system.

To this day, pelicans flock to the islands.

"It is the largest single nesting colony for brown pelicans in the country," said Byron Fortier of the U.S. Fish and Wildlife Service.

The brown pelican has been on the endangered species list since the birds were wiped out in Louisiana in the 1960s by chemicals such as DDT. The birds ate fish carrying the chemicals. In the 1970s, the wildlife department reintroduced pelicans brought in from Florida.

Roosevelt visited the islands in 1915. He later wrote: "I was very glad to have seen this bird refuge. With care and protection the birds will increase and grow tamer and tamer, until it will be possible for any one to make trips among these reserves and refuges, and to see as much as we saw, at even closer quarters."

It was the only refuge of the ones he signed into being that Roosevelt got a chance to visit.

"It's sad to see how much of the refuge has disappeared in the last 100 years," said Douglas Brinkley, a presidential historian who has written about Roosevelt the naturalist and conservationist.

"What used to be a beautiful bird sanctuary now is a shell of its former self. Roosevelt would be amazed how fast coastal Louisiana is eroding away."

Hurricane Ivan's storm surge left many of the Chandeleur Islands in the Gulf of Mexico underwater.