He did not publish his first ornithological paper until 1899. From 1900 he went on an ornithological expedition abroad almost every year until his death, which resulted in a number of papers on the birds of the countries he visited. While at Appleton he actively encouraged ornithological study at
Oxford University, welcoming interested students to his home. In 1922 he founded the
Oxford Ornithological Society and was president until his retirement in 1925. This society led in later years to the formation of the
British Trust for Ornithology and the
Edward Grey Institute of Field Ornithology. He organized and led the
1921 Oxford University Spitsbergen expedition. Jourdain produced several ornithological papers, although many were started but never finished, and authored or contributed to a number of books, notably the sections on Breeding-habits, Distribution Abroad and Food in the
Handbook of British Birds (1938–41). He was assistant editor of
British Birds, the "illustrated (monthly) magazine devoted to the birds on the British list", from 1909 onwards (until his death in 1940). He was also assistant editor of
The Ibis from 1931 onwards and co-editor of
The Oologists Record from 1935 onward. He joined the
British Ornithologists' Union in 1899, serving on the committee including as vice-President in 1934, joined the
British Ornithologists' Club in 1905, was a member of the British List Committee for many years and was a founding member of the British Oological Association, of which he was president from 1932 to 1939. He was also a member of the
International Ornithological Committee, an Honorary Fellow of the
American Ornithologists' Union and an Honorary Member of the ornithological societies of France, Germany, Holland and Hungary. He led the first Oxford University Expedition to
Spitzbergen and travelled extensively in
Europe and
North Africa. He served as President of the Oxford Ornithological Society and was associated with many other ornithological bodies. Jourdain gained a reputation for his temper and went by the nickname of
Pastor Pugnax. He retired in 1925, initially to
Norfolk and then to
Southbourne in
Bournemouth two years later. He continued active field ornithology, writing and regularly attending ornithological gatherings right up until his death. Jourdain died in Southbourne on 27 February 1940, aged 75. ==Publications==