Scientists know little about long-term effects on Gulf Coast birds

Kenneth Gautreaux, Rohwer, Frank C, Stouffer, Philip C., Reed, Donald P.

News Release Distributed 07/15/10

The Deepwater Horizon oil spill has not only tested the limits of human engineering, but also the scientists who study birds along the Gulf Coast. Avian scientists are finding there is little knowledge and direction as to what recommendations should be undertaken to remedy oil-soaked birds and the long-term effects of oil in their habitat.

A problem facing LSU AgCenter conservation biologist Phil Stouffer is the lack of previous studies to learn from because of the uniqueness of this oil spill.

“It is true that birds can be cleaned and released, but whether or not they will return to a breeding population is not very well-known,” Stouffer said.

Capturing birds can be a difficult task, and Stouffer is concerned that venturing into nesting colonies to rescue an oiled bird could be counterproductive, especially during the breeding season. He cites the brown pelican, the Louisiana state bird, as a prime example of the dilemma facing rescuers.

“They are very sensitive to disruptions, so for instance, if birds are scared off their eggs while incubating, with the temperatures we’re exposed to, it won’t take long before the eggs are no longer viable,” Stouffer said. “Further, young birds are vulnerable to oiling if they try to escape by running along the ground or climbing through oiled mangroves.”

Don Reed, a wildlife specialist with the LSU AgCenter, said birds can be exposed to the oil in several ways. “Birds are especially at risk because they can have direct physical contact with the oil, ingest it, inhale or directly absorb oil through their skin,” Reed said.

Reed said oil reduces the insulation value of the bird’s feathers. Heavily oiled birds will lose their ability to fly and their ability to remain buoyant while resting on the water. “A bird that is unable to fly is much more likely to fall victim to a predator,” Reed said.

Reed echoes Stouffer’s concern in that there is not a large body of knowledge about the long-term effects of oil exposure on both birds and mammals. Some studies have indicated that significant exposure to oil has caused suppression in immune systems and impaired reproduction in animals.

Stouffer indicated that an oil spill in South Africa may provide some beneficial information. Scientists there looked at the spill’s influence on penguins and found that some cleaned birds returned to breed. The similarities between penguins and brown pelicans may provide some insight as to what to expect from oiled pelicans. Both penguins and pelicans eat fish, nest in colonies and are long-lived.

Shore birds are battling not only oil that washes ashore, but also the influx of humans into their environment. Shore birds make nests and search for food along the beach. With the increase of human activity along the beachfront from cleanup operations, these birds can have difficulty foraging for food, and workers could unintentionally damage nesting sites.

Stouffer said that with the height of the hurricane season approaching, a dire situation could be made much worse if a storm surge would move oil much farther inland.

“We could potentially have oil much farther inland, and a larger group of birds such as waterfowl, eagles, herons and other aquatic species that live inland would be at risk,” Stouffer said. “For overwintering waterfowl, it could be devastating.”

Frank Rohwer, an avian ecologist who specializes in waterfowl in the LSU AgCenter’s School of Renewable Natural Resources, said the effects of the spill on waterfowl will not be known until ducks and geese begin arriving starting in late August and early September. Much like many other scientists studying the spill, Rohwer is unsure of how far-reaching the effects of oil will have on ducks and other migratory waterfowl.

“It could be potentially devastating or the effects could be minimal,” Rohwer said. “Certainly, diving ducks that raft in large numbers in open waters along the coast will be at greater risk because of the proximity to areas that have been oiled.”

He said duck species such as canvasbacks, redheads and scaup would be more likely to encounter oil than dabbling ducks such as mallards, teal and gadwall.

Rohwer said barring an event such as a tropical storm or hurricane, waterfowl whose primary habitat is interior marshes should be spared from the effects of the spill.

“We shouldn’t see oil in these areas unless a storm surge occurs. If that happens, it would be very damaging to even dabbling species,” Rohwer said.

The long-term effects of oil on wildlife in Louisiana may not be known for several years. If habitat destruction is widespread, it could lead to shifts in population structures and change the diversity of Louisiana’s coastal ecosystems.

Craig Gautreaux
1/4/2011 1:10:12 AM
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