<p>A heavily oiled brown pelican rests on Queen Bess Island in Louisiana’s Barataria Bay. The bird is one of the countless victims of BP’s Gulf oil spill, which unleashed some 4.9 million barrels of oil into the Gulf of Mexico. (Each barrel of oil equals 42 gallons or 159 liters.)</p> <p>U.S. Fish and Wildlife Service statistics report that 3,634 dead birds and 1,042 live oiled birds had been collected by rescue workers as of September 14. Among that tally were 376 dead brown pelicans and 192 found alive but immersed in oil.</p> <p>Millions of the Gulf of Mexico’s migratory and resident birds may be placed at some level of risk due to the disaster.</p> <p>Read more in the October 2010 issue of<i> National Geographic</i> magazine.</p>