Mother Nature Network: Four years after the largest oil spill in U.S. history, wildlife in the Gulf of Mexico is still struggling to recover, according to a recent National Wildlife Federation report. The report focused on 14 species affected by the spill and used data from independent scientists and the National Ocean and Atmospheric Administration. It found that many species, particularly bottlenose dolphins and sea turtles, are dying in record numbers, and the NWF says the animals' deaths are connected to the Gulf...