Birds and their habitats studied for BP spill effects
29th May 2012 · 0 Comments
By Susan Buchanan
Pelican eggs washed away this spring on a Plaquemines Parish island eroded by oil, and traces of oil and Corexit were found recently in eggs from Minnesota pelicans that winter in the Gulf. Scientists have collected data on birds for Natural Resource Damage Assessments, or joint government and BP studies of the spill’s impacts. That information will be used by the feds in the BP spill trial, scheduled for January in U.S. District Court in New Orleans. BP may introduce its own findings on birds then, according to wildlife experts.
The U.S. Fish and Wildlife Service counted 6,147 dead and 3,046 injured birds in the Gulf during the 12 months after the spill began in late April 2010.
David Muth, the National Wildlife Federation’s Louisiana state director, said last week “the federal numbers on birds lost to the spill are minimums, and we can assume multiplier effects for birds that died and sank or disappeared in other ways.” Actual losses are larger than the data indicate, he said in New Orleans. Years after the 1989 Exxon Valdez spill, estimates of resulting bird deaths and injuries ballooned to 250,000.
Muth discussed the impact of the spill on brown pelicans, which were removed from the endangered species list in November 2009. “Brown pelicans were on a long trajectory of recovery before the spill,” he said. “They were doing very well, considering they had ceased to breed on the northern Gulf Coast 50 years before. They had recovered to that point that they could take a big hit, and they got it from the spill.” Brown pelicans are Louisiana’s state bird.
The spill’s impact on brown pelican numbers is unknown at this juncture, he said. “These are long lived birds,” he said. “Earlier, when pelican populations were impacted by DDT, they continued to survive for many years until breeding stopped.” DDT was banned as an insecticide in the U.S. in 1972.
“Even if the current size of the pelican population were known, it would only tell us so much because at the sublethal level, oil in the environment is taken up by fish, resides in fish tissue and ends up in pelican tissues,” Muth said. “We won’t know the long-term effects of that for awhile but we will see an impact.”
Nesting areas in Barataria Bay, including islands of mangrove trees—where pelicans lay eggs—were hit hard by oil, Muth said. “Islands where birds nest are eroding away,” he noted. BP oil killed vegetation on islands that were already shrinking as the ocean rises, and hastened the land’s disappearance.
Chris Macaluso, coastal coordinator with the Louisiana Wildlife Federation, said in addition to pelicans, the spill hurt terns, gulls, green herons and many other species. “It wasn’t so much birds being covered with oil as it was the impact of the oil cleanup on their habitat,” he said. “Equipment brought on beaches interfered with tern nest sites, and boom to contain oil was placed around small rookeries. Human activity, like laying boom and retrieving it later, interfered with habitat.”
The cleanup disrupted birds as workers stomped around with shovels, and fishermen employed by BP tossed boom from boats and leaned out to mop oil from marshes. In July 2010, the American Bird Conservancy said that cleanup efforts had disturbed nesting and noisy, air boats had flushed pelicans and terns from roosting sites.
Last week, Plaquemines Parish officials said tides this spring swept away brown pelican nests built earlier in the year on Cat Island in Barataria Bay. Chicks and eggs are gone. According to the parish, BP oil killed mangroves, which helped to hold the island together and gave birds a place to nest. With few mangroves left on the island, pelicans built nests on the ground early this year.
The parish and state are asking BP for funds to build a barrier around 40 acres of Cat Island. The plan is to build smaller islands within the protective barrier, and to plant mangrove trees. Last week, Plaquemines Parish Coastal Director P.J. Hahn said small islands off the coast are among the few nesting grounds left for many threatened and endangered birds, and are free of natural predators.
In Louisiana, piping plovers are a threatened species and interior least terns are endangered.
Macaluso said small islands don’t have the racoons, skunks, dogs and feral cats found on bigger islands. He said the Louisiana Wildlife Federation and other organizations have encouraged NRDA researchers to study the role of little islands as bird habit. “Sometimes a small island is the only refuge in a large stretch of open water, and birds and fish need them in addition to bigger, barrier islands,” he said.
Meanwhile to our north, Minnesota researchers have found petroleum compounds and Corexit, used to disperse BP oil in the Gulf, in the eggs of nesting pelicans. Scientists are studying impacts of the BP spill on North America’s biggest colony of white pelicans at Minnesota’s Marsh Lake, which hosts an estimated 34,000 adult birds raising 17,000 chicks a year.
“Petroleum compounds were present in 20 of the first batch of 22 Minnesota pelican eggs tested recently, and 18 of these eggs also contained Corexit,” said Carrol Henderson, nongame program supervisor at the Minnesota Dept. of Natural Resources. Pelicans were exposed to oil in 2010 and subsequent years. Most of the white pelicans winter in the Gulf, and their young spend a full year down south before they start breeding.
“In particular, the Corexit found in the eggs appears to be pretty closely tied to the spill,” Henderson said. Minnesota researchers are concerned that pelicans and loons wintering on the coast came into contact with polycyclic aromatic hydrocarbons—known to cause cancer and birth defects in animals—and Corexit, which contains cancer-causing chemicals and endocrine-disrupting compounds, he said.
Henderson said “lab tests are being conducted on Minnesota loon eggs and on tissue samples from adult loons, with results expected soon.” After loons spend two years in the Gulf—mainly Florida and Alabama—they return to Minnesota in the third year.
Starting in 2010, a government program enticed birds into fields and away from oil in the Gulf. “We needed more habitat before the spill because of wetlands loss, and we needed it during and after the spill because of the oil,” Macaluso said. The 2010 Migratory Bird Habitat Initiative or MBHI provided food sources for ducks and other migratory birds. With $40 million in funding, the Natural Resources Conservation Service (NRCS) enrolled 470,000 acres owned by farmers and others in the Gulf states, Arkansas, Missouri and Georgia. Landowners were paid to create mudflats and shallow water areas, and south Louisiana rice farmers eagerly participated.
Alexandria-based Tim Landreneau, state program specialist with the NRCS, said “an estimated 36 percent of the total energy needed to support target duck populations across south Louisiana was satisfied on 176,821 acres of MBHI lands in southwest Louisiana” in 2010. Waterfowl food needs are often monitored in duck energy-days or what’s needed to support a duck.
As for NRDA, the U.S. Dept of the Interior has conducted a number of studies along the Gulf assessing oiling and mortality of colonial water birds, pelagic birds and secretive marsh birds, and injury to piping plovers. Atlanta-based Nanciann Regalado, spokeswoman for the Dept. of the Interior, said “the field collection of data is complete and data analysis is ongoing” in those bird studies.
The NRDA process has some drawbacks. Muth said “we don’t do a good job as nation of keeping track of wildlife so we’re missing baseline or pre-spill data to assess what the spill did.” And he said “There’s a structural problem with the way NRDA is set up. It takes a awhile to get research projects approved.”
In NRDA studies, government and university scientists collaborate with BP representatives. The oil company is also gathering its own information on the spill’s impact on birds, other wildlife and fish. Muth said “results of many of these studies won’t be released until the BP trial starts in January because they’ll be used as evidence by the different sides.” BP hired Houston-based environmental contractor Cardno ENTRIX shortly after its Gulf well exploded to provide consulting on NRDA and the spill response. Cardno ENTRIX employees have represented BP in NRDA studies.
As to whether oil should have been removed from birds during the spill, Muth said cleaned birds were tagged, and NRDA studies are expected to provide information about survival rates. In 2010, European scientists warned that birds cleaned of oil would only die soon afterwards, and the World Wildlife Fund also questioned the practice.
This article was originally published in the May 28, 2012 print edition of The Louisiana Weekly newspaper