 In 1902, in 'The Little White Bird', J M Barrie refers to sheep in Kensington Gardens nibbling the grass in nervous agitation immediately after being shorn, and to Solomon, the wise crow, drinking water when he was frustrated and outwitted in an argument with other birds.Another bird encourages him to drink in order to compose himself.These references to displacement activities in a work of literature indicate that the phenomenon was well recognized at the turn of the twentieth century.