one recent action by the Interior Department drew unprecedented protest from a bipartisan group of top officials who go all the way back to the Nixon administration: a new legal opinion that attempts to legalize the unintentional killing of most migratory birds. Under the new interpretation, the Migratory Bird Treaty Act forbids only intentional killing – such as hunting or killing birds to get their feathers – without a permit. The administration will no longer apply the act to industries that inadvertently kill a lot of birds through oil drilling, wind power and communications towers. Critics fear that these industries might now end the bird-friendly practices that save large numbers of birds. The 1918 Migratory Bird Treaty Act makes it illegal to kill birds without permission, though hunters can obtain permits. For decades, the threat of prosecution gave industries that unintentionally kill a lot of birds an incentive to collaborate with the federal government on minimizing bird deaths. For instance, hundreds of thousands of birds die each year from getting poisoned or trapped in the toxic muck of drilling companies’ wastewater pits. To remedy this, oil and gas companies can store the waste in closed tanks or put nets over their pits to limit the number of deaths.In other industries, fishing boats that drag long lines with baited hooks accidentally drown albatross, petrel and other seabirds. After working with the U.S. Fish and Wildlife Service, fishing companies started attaching weights to their lines so they descend more quickly into the water. At communications towers, neotropical songbirds, especially warblers, are attracted to the steady red lights that warn pilots, and as a result millions are killed each year. So the industry, working with several government agencies, figured out that flashing lights — which don’t attract birds — are just as good at preventing airplane collisions. It’s a cheap fix, because the towers already have strobe lights; they just have to turn off the steady ones.Companies that refused to cooperate risked criminal prosecution. Duke Energy and PacifiCorp Energy both were prosecuted during the Obama administration for failing to take steps to protect birds at their Wyoming wind farms, despite the U.S. Fish and Wildlife Service’s efforts to get them to do so.