American-born businessman and ornithologist. Phelps amassed a tremendous collection of birds in his adopted home of Venezuela in the early 20th century, establishing a museum to preserve them. On his numerous expeditions (to which he devoted himself after retiring from a career in business), he also collected other animals and some plants.

William Henry Phelps was born in New York City, the son of a lawyer. He graduated from Harvard College in 1897, having interrupted his studies to make an ornithological expedition to Venezuela, the results of which he presented to the American Museum of Natural History. He returned to Venezuela to set up a business exporting coffee and met his future wife, Alicia Tucker, in San Antonio de Maturin. Together they had four children, John Prince, William Henry Jr (who also became an ornithologist), Luisa and Alberto.

In 1903 Phelps moved his headquarters to Caracas and began dealing in manufactured goods as well as serving as a Venezuelan correspondent for the New York Herald. His successful business allowed him to partake in and finance many more expeditions to collect birds from remote parts of the country and the border areas of Guyana, Brazil and Colombia, also picking up a few plants. He collaborated with other scientists including Bassett Maguire of the New York Botanical Garden, in their surveys, and was constantly accompanied by his son William H. Jr (Billy) and Billy's wife, Kathleen Deery de Phelps. Phelps authored many articles and with his ornithologist son co-authored a two-volume book on the birds of Venezuela. As well as various new bird species, a new plant genus was named after him and numerous honours were conferred upon him in Venezuela and the United States. He established a public library in San Antonio and left his museum of birds to the nation.