The refuge shall be established and maintained (a) as a refuge and breeding place for migratory birds included in the terms of the convention between the United States and Great Britain for the protection of migratory birds, concluded August 16, 1916, and (b) to such extent as the Secretary of the Interior may by regulations prescribe, as a refuge and breeding place for other wild birds, game animals, fur-bearing animals, and for the conservation of wild flowers and aquatic plants, and (c) to such extent as the Secretary of the Interior may by regulations prescribe as a refuge and breeding place for fish and other aquatic animal life.
16 U.S. Code § 723 - Purposes of refuge; regulations by Secretary of the Interior
Reorg. Plan No. III of 1940, § 3, eff. June 30, 1940, 5 F.R. 2108, 54 Stat. 1232, set out in the Appendix to Title 5, Government Organization and Employees, consolidated Bureau of Fisheries and Bureau of Biological Survey into one agency in Department of the Interior to be known as Fish and Wildlife Service.
Reorg. Plan No. II of 1939, set out in the Appendix to Title 5, transferred Bureau of Fisheries in Department of Commerce and its functions to Department of the Interior; transferred functions of Secretary of Commerce relating to protection of fur-bearing animals to Secretary of the Interior; and transferred functions of Secretary of Agriculture relating to conservation of wildlife, game, and migratory birds to Secretary of the Interior.