Not so long ago, the Pelican State lost its namesake bird.

A chemical used to kill insects also induced the animals to lay eggs with too-thin shells.

"Instead of eggs, heavily DDT-infested Brown Pelicans and Bald Eagles tend to find omelets in their nests, since the eggshells are unable to support the weight of the incubating bird," Stanford researchers have written.

Today, the brown pelicans are back, and wildlife scientists are celebrating 50 years since the species was reintroduced to the Louisiana coast. While it's a cause for celebration, researchers also warned that the fight is not over because coastal birds continue to lose their nesting grounds.

In the early 1960s, pollution from dichlorodiphenyltrichloroethane — or DDT — killed off the last Louisiana brown pelicans. In 1968, the state decided to start shipping in young birds from the Atlantic coast of Florida to the rookeries of Queen Bess Island in Barataria Bay, biologist Todd Baker told the state Wildlife and Fisheries Commission recently.

At the time, scientists didn't know much about how to capture, transport and reintroduce birds, so they chose chicks between 8 and 12 weeks old — strong enough to make the trip but too young to have their flight feathers yet. Scientists would bring the birds fish twice a day until they were old enough to fly, Baker said.

Three years later, in 1971, the birds who imprinted on Queen Bess Island returned to lay 11 nests — the first in a decade. The U.S. banned DDT the following year.

All told, Louisiana relocated 767 pelican chicks through 1976, and the population continued to grow such that the birds were removed from the endangered species list in 2009.

Today, brown pelicans nest along the coast of Louisiana. Locations include Cameron, Jefferson, Lafourche, St. Bernard and Terrebonne parishes, according to the Louisiana Department of Wildlife and Fisheries.

“To think that we almost lost our state bird, the brown pelican, is inconceivable,’’ Wildlife and Fisheries Secretary Jack Montoucet wrote in a statement.

“As many drive along Louisiana’s coastal region and see the pelican flying above, it is easy to take for granted their great abundance. The job now is to make certain the species continues to flourish."

Since their return, these birds have steadily lost their rookeries, forcing pelicans to flee to the Texas coast. Those that stay in Louisiana often must make do with less ideal nesting grounds, like coastal habitats where the ridges aren't as high, Baker said.

The 2010 Deepwater Horizon oil spill also damaged the population. State officials don't have an exact number, but about a quarter of the dead birds collected from the disaster were pelicans. About 1,000 birds of all types were killed just on Queen Bess Island, where many pelicans nest, Baker said.

Louisiana received about $148 million from the oil spill to clean up coastal rookeries. A pair of projects are in the design phase right now. The first would shore up Rabbit Island in southwest Louisiana, and the other would help fill in area around Queen Bess Island that's sunken due to subsidence and turned to open water.

It's a balancing act for scientists, who must rebuild enough land to expand the nesting grounds without making the island so large and high that predators move in, predators the birds seek to avoid by laying their eggs on islands, Baker said.

Wildlife and Fisheries is working with the state's Coastal Protection and Restoration Authority to repair the rookeries, which are seen as indicators of the health of the entire Louisiana coast.

“In Louisiana we share our living space with more species of the animal kingdom than just about anywhere else in America. If we cannot save the habitat for those species, we cannot save it for ourselves. And as Queen Bess Island proves, every foothold of land is vitally important," authority Chairman Johnny Bradberry wrote in a statement.

Still, on the 50th anniversary of the reintroduction of the brown pelican, state leaders are reminded that with careful intervention the birds' population has rebounded from extinction before.

"It's a feel-good story," Baker said. "We now have pelicans back in the Pelican State."

Follow Steve Hardy on Twitter, @SteveRHardy.