Food and Migration Habits of the Eastern Kingbird in Panama

Food and migration habits of the Eastern Kingbird in Panama.--The Eastern Kingbird (Tyrannus tyrannus), a species breeding in temperate North America chiefly east of the Rocky Mountains, is an abundant diurnal migrant through the Isthmus of Panama. It rarely winters in southern Middle America, most of the population moving to South America. I studied kingbird movements in the Panama Canal Zone in 1965-66 and again in 1970. The northward and southward migrations differed in several ways that seem to be correlated with food resources available to the birds in Middle America.