In my field study I was helped by my son, John H. Fitch, who climbed to many kite nests and spent many hours observing in the field. My daughter, Alice V. Fitch, likewise aided me by keeping nests under surveillance. Dr. Claude W. Hibbard of the University of Michigan and Mr. Harry Smith, superintendent of Meade State Park, also kindly provided much useful information concerning the history of the colony of Mississippi kites at the Park. Mr. William N. Berg analyzed pellets, and Dr. George W. Byers kindly checked many of the identifications, and provided generic and specific determinations for some of the insects. In general, the range, habits and ecology of the Mississippi kite are already well known through the publications of Audubon (1840), Chapman (1891), Bendire (1892), Ganier (1902), Wayne (1910), Nice (1931), Bent (1936), Sutton (1939) and Eisenmann (1963). The breeding range is the southeastern United States, chiefly within the Austroriparian Life-zone, but extending northwest through much of Oklahoma and into southern Kansas. The species is highly migratory. Wintering Mississippi kites are known from Argentina and Paraguay (Eisenmann, _op. cit._:74), and most of the population probably winters in southern South America, but records outside the breeding range are few. The Mississippi kite is perhaps one of the most social raptors. It is highly gregarious, not only in its migrations but in breeding colonies. All breeding pairs seen were closely associated with other individuals, with no territorial hostility; signs of intraspecific intolerance are rare, even where the kites are abundant. In the nesting season many of both sexes perch together in the same tree, and groups tend to keep together as they forage. Secondary sexual differences are slight. Seven males in the University of Kansas Museum of Natural History collection average 351 (342 to 360) millimeters in length, and six females average 361 (348 to 370) millimeters. Sutton (_op. cit._:44) collected 16 breeding kites near Arnett, Oklahoma in 1936 and 1937 and recorded that eleven males averaged 245 (216 to 269) grams and five females averaged 311 (278 to 339) grams. As indicated by Sutton, the head is paler in the adult male than in the female, and at close range this difference will serve for identification of the sexes. The difference in size is scarcely noticeable in the field. Habitat