With the advice of Elihu Root, McLean immediately introduced new legislation giving the president the power to negotiate a treaty to regulate the hunting of migratory birds; this bill was passed in July 1913. The Migratory Bird Treaty with Great Britain (acting for Canada) was signed in 1916, and the Migratory Bird Treaty Act to ratify and implement the treaty was passed in 1918.
McLean's legislation granting the president authority to negotiate a treaty for regulating migratory bird hunting led to the signing of the Migratory Bird Treaty with Great Britain (representing Canada) in 1916, which was followed by the passage of the Migratory Bird Treaty Act in 1918.