Alexander Wetmore, 92, a retired secretary of the Smithsonian Institution and a renowned ornithologist, died of congestive heart failure Wednesday at his home at High Point in Montgomery County.

Dr. Wetmore was secretary of the Smithsonian from 1945 until 1952. But his association with the institution began in 1924, when he was named superintendent of the Smithsonian's National Zoological Park, and continued until long after his retirement as secretary. For he continued to do research on birds and avian fossils in a laboratory at the Smithsonian until about a year before his death.

On his 90th birthday, the Smithsonian published "The Collected Papers in Avian Paleontology Honoring the 90th Birthday of Alexander Wetmore." S. Dillon Ripley, the secretary of the Smithsonian, then wrote:

"Truly the incessant and intensive zeal which he has single-mindedly given to the study of birds over the years, often at very considerable personal expenditure in time and energy, will mark the career of Alexander Wetmore as one of the most memorable in the entire history of American ornithology."

Dr. Wetmore was superintendent of the National Zoo for less than a year. In 1925, he became assistant secretary for science of the Smithsonian and director of its Museum of Natural History. He remained assistant secretary until he became secretary.

During his tenure, the Musem of Natural History received 26,058 animal and bird skins from North America, Puerto Rico, Hispaniola, the Hawaiian Islands, and South and Central America. Dr. Wetmore himself contributed 4,363 specimens and collected 201 clutches of eggs. In the course of his career, he described 189 species and subspecies of birds that previously had been unknown to science.

He was the author of numerous articles and longer works. His "A Classification for the Birds of the World" is considered a classic. Among his other books are "Song and Garden Birds of North America," "Water, Prey, and Game Birds of North America," "Fossil Birds of North America," "The Migration of Birds," and "The Book of Birds."

He had published three volumes of "The Birds of the Republic of Panama" by the time of his death. A fourth volume is scheduled for publication.

Dr. Wetmore was born in North Freedom, Wis. He became interested in natural history when he was growing up and by the time he was 19 he was an assistant at the University of Kansas Museum.

He began his government service in 1910, when he joined the Biological Survey, then a part of the Department of Agriculture. He earned a bachelor's degree in biology from the University of Kansas in 1912 and then came to Washington as an assistant biologist in the survey.

During the next 12 years he studied migrant shore birds in South America, brown pelicans in Florida, lead poisoning in wild fowl in Utah, and led an expedition to the mid-Pacific that was sponsored by the survey and by the Bishop Museum in Honolulu. He earned a master's degree from George Washington University in 1916 and a doctorate in 1920.

In addition to his work at the Smithsonian, Dr. Wetmore served on the committees of several international congresses on science and ornithology. He was a member of the board of trustees of the National Geographic Society and vice chairman and acting chairman of the society's committee for research and exploration from 1937 to 1974, when he became chairman emeritus. In 1975, he was awarded the society's Hubbard Medal for his work.

Dr. Wetmore also was a president of the Explorers Club and the Cosmos Club and a vice president of the Boone and Crockett Club. He was a trustee of George Washington University and a member of the National Academy of Sciences.

He received honorary degrees from George Washington University, the University of Wisconsin, Ripon College, and Centre College in Kentucky.

Survivors include his wife, Beatrice, of the home, and a daughter, Margaret Wetmore Harlan, of Gloucester, Va.

The family suggests that expressions of sympathy be in the form of contributions to the Alexander Wetmore Fund of the American Ornithological Union, c/o the Museum of Natural History, Washington, D.C., 20560.