What scientist discovered migration routes in zoology?

Frederick Albert "Fred" Urquhart C.M. is a Canadian zoologist who had studied the migration of monarch butterflies he also identified its migration routes, discovered that the migration spans multiple generations of butterflies

Frederick Albert "Fred" Urquhart C.M. (December 13, 1911 – November 3, 2002) was a Canadian zoologist who studied the migration of monarch butterflies, Danaus plexippus L. Together with his wife, Norah Roden Urquhart (June 23, 1918 – March 13, 2009),[2] he identified their migration routes, discovered that the migration spans multiple generations of butterflies, and after many years of searching found, along with Catalina Trails and Ken Brugger, where the butterflies spend their winter, far away from their summer residence areas in Canada and the United States.