December 28, 2013 marked the 40th birthday of the Endangered Species Act (ESA), which was signed into law by President Richard Nixon on December 28, 1973. According to Sally Jewell, the Secretary of the Interior: “This landmark law has helped to stop the slide toward extinction of hundreds of species. Along the way, we have strengthened partnerships among states, tribes, local communities, private landowners and other stakeholders to find conservation solutions that work for both listed species and economic development.” Supporters of the Act credit it for bringing several species, including the bald eagle (Haliaeetus leucocephalus), the black-footed ferret (Mustela nigripes), and the peregrine falcon (Falco peregrinus), back from the brink of extinction. Some critics believe that animals listed under the ESA are slow to recover and that the law could be improved to better protect imperiled species, while others believe that it imposes unacceptably high costs on society that are not justified by the benefits it affords listed species.