North American Bird Phenology Program

While teaching on the White Earth Indian Reservation in Minnesota, Cooke began noting the arrival dates of migratory birds.

His success sparked the interest of the newly formed American Ornithologists' Union (AOU), who convened a committee on the distribution and migration of birds and chose C. Hart Merriam to be its chief.

The AOU expanded the volunteer network to include the entire United States, Canada, and a portion of the West Indies.

The program outgrew the capabilities of the AOU and was then passed, in the late 1880s, to the Division of Economic Ornithology where it reached its greatest extent of 3000 volunteers.

Notably, Wells Cooke, became a member of the newly formed American Ornithologists' Union in 1884, elected in part due to papers he published while teaching in the Mississippi Valley.

Cooke also began an appointment with the Biological Survey in the U.S. Department of Agriculture in 1901 which lasted for 15 years, in which he published many publications on bird migration and distribution.