For the next 15 years, Stroud lived amongst the canaries that were brought to him by visitors, and became an expert in birds and ornithological diseases. But after being ordered to give up his birds in 1931, he redirected his energies to writing about them and published his first book on ornithology two years later. When the publisher failed to pay Stroud royalties because he was barred from filing suit, Stroud took out advertisements complaining about the situation. Prison officials retaliated by sending him to Alcatraz, the federal prison with the worst conditions.

In 1943, Stroud’s Digest of the Diseases of Birds, a 500-page text that included his own illustrations, was published to general acclaim. In spite of his success, Stroud was depressed over the isolation he felt at Alcatraz, and he attempted suicide several times. The legendary “Birdman of Alcatraz” died in a Missouri prison in 1963 at the age of 73.