While at Leavenworth in 1920, Stroud found a nest with three injured sparrows in the prison yard, and raised them to adulthood. Prisoners were sometimes allowed to buy
canaries, and Stroud had started to add to his collection. He occupied his time raising and caring for his birds, which he could sell for supplies and to help support his mother. According to Stroud, he used a "razor blade and nail for tools" and made his first bird cage out of wooden crates. Soon thereafter, Leavenworth's administration changed, and William Biddle took over as warden. Impressed with the possibility of presenting Leavenworth as a progressive
rehabilitation penitentiary, Biddle furnished Stroud with cages, chemicals, and stationery to conduct his ornithological activities. Visitors were shown Stroud's aviary, and many purchased his canaries. Over the years, he raised nearly 300 canaries in his cells. He also wrote two books, the 60,000-word treatise
Diseases of Canaries (1933), which was smuggled out of Leavenworth, and a later edition, ''
Stroud's Digest on the Diseases of Birds'' (1943), with updated, specific information. He made several important contributions to avian pathology, most notably a cure for the hemorrhagic
septicemia family of diseases. He gained respect and also some level of sympathy in the bird-loving field. Stroud's activities created problems for the prison management. According to regulations, each letter sent or received at the prison had to be read, copied, and approved. Stroud was so involved in his business that this alone required a full-time prison secretary. Additionally, most of the time, his birds were permitted to fly freely within his cells, and because of the great number of birds he kept, his cell was filthy. In 1931, an attempt to force Stroud to discontinue his business and get rid of his birds failed after Stroud and one of his mail correspondents, a bird researcher from
Indiana named Della Mae Jones, made his story known to newspapers and magazines. A massive letter campaign and a 50,000-signature petition sent to President
Herbert Hoover resulted in Stroud being permitted to keep his birds. Despite
prison overcrowding, he was even given a second cell to house them. However, his letter-writing privileges were greatly curtailed. Jones and Stroud grew so close that she moved to Kansas in 1931 and started a business with him, selling his avian medicines. Prison officials, fed up with Stroud's activities and their attendant publicity, intensified their efforts to transfer him from Leavenworth. Stroud discovered a Kansas law that forbade the transfer of prisoners married in Kansas. To this end, he married Jones by proxy, which infuriated the prison's administrators, who would not allow him to correspond with his wife. Prison officials were not the only ones perturbed with Stroud's marriage; his mother was also incensed. They had a close relationship, but Elizabeth Stroud strongly disapproved of the marriage to Jones, believing women were nothing but trouble for her son. Whereas previously she had been a strong advocate for her son, helping him with legal battles, she now argued against his application for parole and became a major obstacle in his attempts to be released from the prison system. After moving away from Leavenworth she had no further contact with him. She died in 1938. In 1933, Stroud advertised in a publication that he had not received any royalties from the sales of
Diseases of Canaries. In retaliation, the publisher complained to the warden and, as a result, proceedings were initiated to transfer Stroud to Alcatraz, where he would not be permitted to keep his birds. In the end, Stroud was able to keep both his birds and canary-selling business at Leavenworth. Stroud mostly avoided trouble for several more years, until it came to light that some of the equipment Stroud had requested for his lab was in fact being used as a home-made
distillery to manufacture alcohol. Officials finally had the wedge they needed to drive Stroud out. Citing his "dangerous tendencies" and longstanding concerns about the sanitary conditions of his cell, they initiated proceedings to send him to Alcatraz. ==Alcatraz==