The subject heading of this Dept. of the Interior memo from Dec. 22 is "The Migratory Bird Treaty Act Does Not Prohibit Incidental Take." To save time, you may want to skip ahead to the Conclusion on page 41. That's the enforcement side. On the legislative side the House Committee on Natural Resources passed an amendment on Nov. 8 that would hold industry not responsible for bird deaths. For more information, follow the links at http://www.audubon.org/news/congresswoman-liz-cheney-introduces-bird-killer-amendment A few years ago some members of Congress attempted to limit enforcement of native bird protection laws by cutting the budget of federal agencies that deal with the International Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act so that the incidental killing (aka "taking") of eagles and migratory birds would not be enforced. It failed to become law. That was then, this is now.
Here is a link to National Audubon's reaction to the Dec. 22 DOI memo: