Brown Pelicans Hit Hard by Oil During Summer, But Populations Still Intact [w/Video]
“Before we even had a chance to celebrate them being taken off the endangered species list, we had the oil spill and they were one of the most impacted birds.”
During the summer of 2010, oiled pelicans became the iconic image of the Gulf oil disaster. Photos of pelicans slowly dying in pools of oil was the catalyst that brought the reality of the disaster to living rooms all across America. Ten months after the start of the disaster, biologists say the brown pelican population on the Gulf Coast is still strong. But while they may have survived the onslaught of oil, some question whether sub-lethal impacts could become a problem later down the line.
Pelicans were just starting their nesting season when the Deepwater Horizon oil rig exploded and sent millions of gallons of oil into the Gulf. It also couldn’t have happened in a worst place—according to the U.S. Fish and Wildlife Service, up to 33,000 pairs of pelicans breed on the barrier islands of the Gulf Coast, with up to 16,000 in Louisiana alone.
Oil washed ashore in some of the largest pelican colonies on Raccoon Island, Pelican Island and Grand Terre Island. Thousands were oiled, injured and killed.
A Celebration Cut Short
The brown pelican was designated as an endangered species in 1970. Due to the use of DDT and other pesticides which tainted the food source, the brown pelican population plummeted in the 1950s and eventually disappeared from the coasts of Louisiana. The 1972 ban on DDT along with management and breeding operations led a growing population and by 2009 it was completely removed from the endangered species list.
“Before we even had a chance to celebrate them being taken off the endangered species list, we had the oil spill and they were one of the most impacted birds,” said Greg Butcher, director of Bird Conservation for the National Audubon Society.
Mike Carloss, Biologist director for Louisiana Department of Wildlife and Fisheries, said of the approximately 5,000 oiled, injured or impacted birds collected on the coast of Louisiana, roughly half were pelicans. While the major impacts happened in the summer, Carloss said they still have the occasional reports of oiled or dead pelicans. He reported a few more dead pelicans in late December, but said there is a fair level of natural mortality that happens during this time of the year.
“I don’t see any spikes in [impacted birds] but we’re still getting the occasional oiled pelicans in Barataria Bay. June and July were the prime months when we were finding [dead or oiled birds],” Carloss said.
Doug Inkley, senior scientist at NWF, said that while the impacts may have seemed profound during the summer, they are unlikely to put the brown pelican back on the endangered species list. Because they range from the Atlantic to Pacific coast, the population impacts on the Gulf Coast shouldn’t significantly impact the species as a whole.
“I am hopeful that as far as a true population impact it will only be local and might only last for a few years. Hopefully the birds will have a successful reproductive season next year,” said Inkley.
Long Term Impacts Remain Unknown
Despite the oiling, Butcher said the birds did manage to have a successful breeding season this summer. Like many biologists, he now worries about the potential for sub-lethal effects in the food chain which could impact everything from feeding to mating habits. The dispersed and submerged oil in the waters surrounding Louisiana's nesting grounds could cause more long term problems.
“The jury is still out now. We’re waiting to see if there could be larger effects that might be more severe. We’re keeping an eye on not only the brown pelican but all fish-eating birds,” Butcher said.
While not meant to minimize the impacts, Carloss said that things “could have been much worse.” At the beginning of the disaster, many biologists, including Carloss himself, feared a widespread kill-off of brown pelicans. He doesn’t believe sub-lethal impacts are out of the question but believes that they will not be much of an issue moving forward. Because brown pelicans often feed on menhaden, which are extremely abundant in Louisiana water and have yet to show any signs of major kill offs or diminished reproduction since the start of the disaster, he doesn’t believe a lack of food will be a concern.
“I don’t want to say it was an insignificant impact but it was not a big blow to the population. More of an issue now, and even before the spill, was the concern about habitat loss,” said Carloss.