I should of done a search and posted this at the beginning of this post rather than going by my memory back to 1972.It is nice to see how well my memory served me.Its also interesting to see that my first bird mount a legally shot great horned owl, would have been illegal just 2 months later.This article explains the amendment wich went into law march 1972. (The Protection of Raptors
The federal protection of migratory birds has a long history in the U.S. dating back to 1916 when a treaty was signed between the United States and Great Britain, on behalf of Canada, for the protection of most migratory birds. This treaty resulted in the enactment of the Migratory Bird Treaty Act (MBTA) in 1918, which is the basic law in effect today. Although raptors such as hawks and owls were not protected by the original Act, they were later included as an amendment in 1972. The bald eagle has been protected since the enactment of the Eagle Act in 1940 and the golden eagle, also under the Eagle Act, since 1962. State laws and regulations today likewise protect all migratory birds.)