Home Biologist Climate change and endangered islands threaten brown pelicans

Climate change and endangered islands threaten brown pelicans


Birds and other creatures in Louisiana live under threat from climate change, endangered islands

CHAUVIN, La. — Sliding over the side of her small boat, seabird biologist Bonnie Slaton wades through waist-deep water, brown pelicans hovering above her head, until she reaches Raccoon Island.

During seabird breeding season, the place is a symphony of sound and movement – ​​one of the few remaining havens for the iconic pelicans.

The crescent-shaped island is a strip of land separating Louisiana from the Gulf of Mexico – a speed bump against storms that come in from the sea. An hour away by boat, the barrier island’s remoteness allows birds to nest on mangroves and sandy beaches at a safe distance from most predators.

A dozen years ago, there were 15 low islands with nesting colonies of the Louisiana state bird. But today, only about six islands in southeastern Louisiana have brown pelican nests – the others have disappeared underwater.

“Louisiana is rapidly losing land,” said Slaton, a researcher at the University of Louisiana at Lafayette. “Sea level subsidence and rise are a double whammy.”

The endangered islands threaten one of the most famous conservation success stories of the past century – the decades-long effort to bring pelicans back from the brink of extinction.

On land, brown pelicans are clumsy birds, their huge beaks and wings lending them what Slaton calls a “clumsy” look. But hovering low over the ocean, pelicans are majestic.

The same forces that are engulfing the coastal islands are also causing southern Louisiana’s saltwater marshes to disappear faster than anywhere else in the country. Scientists estimate that Louisiana loses a football field every 60 to 90 minutes.

“We are on the front lines of climate change. It all happens here,” said Jimmy Nelson, an ecologist at the University of Louisiana at Lafayette.


As Slaton and two other biologists walk the shore of Raccoon Island, the birds land in a swirling, plunging cacophony that heralds intruders. The calls of a thousand laughing gulls are loud enough to drown out human thought.

Slaton swaps out batteries and memory cards for 10 motion-activated trail cameras set up to observe pelican nests in varying habitats. Some circular cordgrass nests are built on top of mangrove stands, others on grassy mounds.

Camera data has shown that in recent years the main threat has been flooding – which can wash away entire nests, as happened in April 2021.

Passing a nest on the ground, Slaton bends down to watch two tiny gray and pink pelican chicks squirm with their eyes still closed. Within a week, the chicks are covered with fluffy white and gray feathers.

Observing a colony of seabirds reveals both the promise and the fragility of new life. Then, suddenly, the biologists wipe white drops from their foreheads.

The abundant bird droppings act as a natural fertilizer that helps shrubs and grass grow from the island’s sand and stones. Their roots slow erosion.


When Mike Carloss was a kid in Louisiana in the 1960s, he never saw brown pelicans.

Like bald eagles, their populations had been decimated by the widespread use of DDT pesticides that thinned eggshells and prevented healthy chicks from hatching.

The beloved pelicans had completely disappeared from Louisiana, their likeness appearing only on the state flag. But a long-running effort to save them has led to an inspiring comeback story.

After DDT was banned in the United States in 1972, biologists brought pelican chicks from Florida to repopulate empty islands across the Gulf of Mexico. More than 1,200 have been released in southeast Louisiana over 13 years.

One location was Raccoon Island, where Carloss, then a teenage field assistant with the Louisiana Department of Wildlife and Fisheries, tossed fish from the beach to feed the chicks.

“I kept these young pelicans on a remote island,” he recalls. “Somebody had to hand-feed them basically.”

As state wildlife biologist for more than two decades, Carloss then oversaw restoration projects on the island. But now he fears that if the islands continue to disappear, “we will be back to the 1960s era, and not because of poisonings”.


Protecting what remains depends on continued human intervention.

Today, one side of Raccoon Island is surrounded by granite breakwaters that divert the tides.

Erosion is a natural process and over thousands of years most barrier islands rise and fall. Unlike the volcanic islands, there is no bedrock here, only layers of silt washed into the Mississippi Delta.

But rising seas and increased frequency and intensity of storms with climate change are accelerating the pace. And the islands have been deprived of new sediment from the Mississippi because the course of the river has been controlled since the 1940s by levees to prevent flooding and facilitate navigation.

Every few years, government agencies strive to restore and maintain some barrier islands. The money comes from a legal settlement after the 2010 Deepwater Horizon oil spill. But that won’t last forever – and many sinking islands aren’t being restored at all.

Another day, the biologists steer their aluminum boat past an unrestored island called Philo Brice. Mangroves grow on the flooded lands and pelicans nest in the upper branches.

It’s still a decent breeding habitat, as long as the soil holds and the plants stay above water. “In five or 10 years, it may or may not be here. It’s that fast,” Slaton said.


When biologist Juita Martinez conducted research on the Louisiana coast between 2018 and 2021, she found that the number of pelicans on another unrestored and flooded island, Felicity, dropped from 500 to around 20.

Brown pelicans can live for over 20 years, so the impact of reproductive issues takes time to become clear.

For now, pelicans are still common on the Louisiana coast, and their likenesses are everywhere – license plates, restaurant signs and university seals.

The brown pelican “is a symbol of Louisiana, just as the eagle is a symbol of America,” said Rue McNeil, executive director of the Northlake Nature Center in Mandeville, Louisiana.

But the future is uncertain.

Flying in a small plane low enough to see the heads of pelicans sticking out of the mangroves, the difference between Raccoon Island and the unrestored Philo Brice is stark: one is solid land, the other like soft bread dissolving into soup of blue.