He is notable for his encyclopedic 21-volume work, Life Histories of North American Birds, published 1919-1968 and completed posthumously.

[1] Following a request from the Smithsonian Institution in 1910, Bent started work on the project that would dominate the rest of his life.

Using his own experiences, the published literature, and contributions from hundreds of others, he put together what was at the time by far the most comprehensive repository of knowledge about the biology of the birds of North America.

His accounts were published progressively in the United States National Museum Bulletin (NMB),[1] and later republished by Dover.

In 1940 Bent was awarded the John Burroughs Medal for distinguished book-length nature writing.