Wildlife affected by the Deepwater Horizon oil spill

The royal tern is a seabird that breeds on the Atlantic and Pacific coasts of the southern US and Mexico. Environmentalists warned that the spill, which covers an area about the size of Cornwall and is just a few miles off the Mississippi river delta, could turn out to be as catastrophic as the impact of the Exxon Valdez tanker spill off Alaska was 21 years ago
Photograph: Getty Images

A brown pelican, the smallest of eight species of pelican found along the east coast of the US, which can live for up to 40 years. Ocean pollution is a common cause of blindness and other injuries in the bird. The most immediate threat from the Deepwater spill is to birds, dolphins and turtles in the area and to the Louisiana coast, as the slick hits the shore
Photograph: David McNew/Getty Images

A group of sperm whales. The best estimate of abundance for sperm whales in oceanic waters of the northern Gulf of Mexico is 1,315, according to the National Oceanic and Atmospheric Administration fisheries department. Environmentalists say the oil is likely to hit the delta and a series of barrier islands that have still not fully recovered from hurricane Katrina six years ago and which are home to more than 400 species. But if the oil continues to spread it could hit Mississippi, Alabama and Florida
Photograph: Reuters

The snowy plover, a ground-nesting bird under threat, is found on unvegetated to sparsely vegetated beaches. An estimated 18,000 snowy plovers breed in North America, where US Pacific and Gulf coasts populations are threatenend by degradation of their habitat from development, human recreation and invasive species, according to the Cornell Lab of Ornithology. The coastguard estimates that 5,000 barrels a day are gushing from beneath the destroyed rig 50 miles off the coast
Photograph: Birdsasart/Getty Images

A sea turtle. All species of sea turtles are listed as threatened or endangered, and are on the IUCN's red list
Photograph: TARIK TINAZAY/AFP/Getty Images

A mottled duck, which lives on the Gulf of Mexico coast between Alabama and Tamaulipas in Mexico
Photograph: Erin Paul Donovan/Alamy

Bluefin tuna, a critically endangered species native to the eastern Atlantic Ocean
Photograph: Brian J. Skerry/Getty Images/National Geographic

The reddish egret is a near-threatened species of small heron which breeds on the Gulf Coast of the United States
Photograph: Arthur Morris/Corbis