Albert M. Day, 81, former director of the U.S. Fish and Wildlife Service, died of renal failure Sunday at the Polyclinic Medical Center in Harrisburg, Pa. He lived in Camp Hill, Pa.

Mr. Day had joined the wildlife service as a field biologist in Wyoming in 1918. He came up through the ranks to become director of federal aid in wildlife restoration in 1938, assistant director of the service in 1943, and director in 1946.

In 1953, with the change in administrations, Mr. Day was replaced as director but continued to serve as an assistant to the director for two years before retiring from federal service.

He then served as director of wildlife research for the Arctic Institute of North America. He was executive director of the Oregon Fishing Commission in Portland until 1960, when he became executive director of the Pennsylvania Fish Commission.

Since retiring from that commission in 1964, he had been a consultant to the National Park Service, the Bureau of Sport Fisheries and Wildlife, the Bureau of Outdoor Recreation and the Bureau of Land Management in Washington.

Mr. Day was born in Humboldt, Neb., and was a graduate of the University of Wyoming.

He was a former national director of the Izaak Walton League of America and had been active in the Wild-life Society, the National Audubon Society, the American Fisheries Society, the Wildlife Management Institute and the International Association of Game, Fish and Conservation Commissioners.

Mr. Day belonged to the Explorers and Cosmos clubs. He was the author of a number of publications in his field.

He is survived by his wife, Eva Kendall Day, of the home; a son, Navy Cmdr. Richard T. Day, stationed in Hong Kong; a daughter, Mrs. Robert Evans, of Madison, Wis.; a foster son, Ernesto Pagan, stationed at the Patuxent (Md.) Naval Air Station; a sister, Bessie Amiss, of Laguna Hills, Calif., and four grandchildren.