In early 19th-century Japan, it became fashionable for the culturally sophisticated theatergoing population of Edo to entertain themselves at parties by imitating the voices and gestures of famous actors. As this fad spread, people began to expand their repertoires by mimicking animals, and as animal poses became all the rage at parties, writers and artists collaborated to produce illustrated books containing model examples of these poses. One such document written by poet Santo Kyoden in 1809 included copies of these Utagawa Toyokuni ukiyo-e prints of men imitating birds.
The work, titled Harasuji Omuseki (?????), consisted of several volumes that also featured poses for animals other than birds. Waseda University has an online copy of Volume 3, which includes the animal poses below.
Crane pose, Owl pose