The Act was enacted in an era when many bird species were threatened by the commercial trade in birds and bird feathers. The Act was one of the first federal environmental laws (the Lacey Act had been enacted in 1900). The Act replaced the earlier Weeks-McLean Act (1913). Since 1918, similar conventions between the United States and four other nations have been made and incorporated into the MBTA: Mexico (1936), Japan (1972) and the Soviet Union (1976, now its successor state Russia). Some of the conventions stipulate protections not only for the birds themselves, but also for habitats and environs necessary for the birds' survival.