Mollie Beattie, 49, a former Vermont environmental official who as director of the U.S. Fish and Wildlife Service during the Clinton administration was the first woman to head the agency, died of brain cancer June 27 at a hospital in Townshend, Vt. She had homes in Alexandria and Grafton, Vt.

Ms. Beattie, who had been treated for brain cancer since last year, resigned her federal office this month because of her health. Ms. Beattie was named to head the U.S. Fish and Wildlife Service in 1993.

She presided over an agency with a shrinking budget, but she worked to expand the federal refuge system and to protect the Endangered Species Act from congressional critics who say the law infringes on the rights of private property owners. During her tenure, she began the process of opening 23 refuge hunting programs and 18 fishing programs.

Ms. Beattie was instrumental in the final stages of a program that reintroduced wolves into the northern Rockies in early 1995.

In her last major speech as director of the Fish and Wildlife Service, she recalled how she released Hope, a rehabilitated bald eagle, into the wild to mark the change in the species' status from endangered to threatened. That day was one of the highlights of her career, and she recorded the event in a journal under the heading: "Is this a great job, or what?"

With her death, "America lost one of its great spirits," President Clinton said in a statement. "Mollie presided over a sea change in the administration of the Endangered Species Act by improving the way government worked." Even congressional leaders who opposed her stands on major issues have supported legislation that would name 8 million acres of the Artic National Wildlife Refuge in Alaska after Ms. Beattie.

In a statement, Secretary of the Interior Bruce Babbitt said the wilderness that will be named after her "symbolizes Mollie's spirit: wilder, more powerful and more free from the influence of man than anywhere else in America."

Ms. Beattie was born on Long Island, and was raised in Connecticut. She was a graduate of Marymount College in Tarrytown, N.Y., and received a master's degree in forestry from the University of Vermont and a master's degree in public administration from Harvard University.

Before moving to Washington, she was executive director of the Richard A. Snelling Center for Government, a public policy institute in Vermont. She had been deputy secretary of the Vermont Agency of Natural Resources and commissioner of the Vermont Department of Forests, Parks and Recreation.

Survivors include her husband, Rick Schwolsky of Grafton; and her mother, Patricia Beattie, and a sister, Jane Beattie, both of Ketchum, Idaho.