Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDS: Alaska, Mackenzie Delta, southern Keewatin, and Maine south to southern California, Mexico, Oklahoma, and Virginia. Has expanded range in eastern North America (especially in the north) in recent decades (see Heusmann 1991 for a detailed account of status in the Atlantic Flyway). WINTERS: southern Alaska and southern Canada to southern U.S., Mexico, Cuba, occasionally Hawaii (AOU 1983). Half or more of the Mississippi Flyway's 3.2 million mallards winter in the lower Mississippi Valley, from Cape Girardeau, Missouri, to the Gulf of Mexico. Also occurs in the Palearctic. Many semiferal populations exist. Availablity of grain allows wintering north of pre-settlement range; now rare in Central America.