The Mexican duck (Anas diazi, and see below) is a dabbling duck in the genus Anas which breeds in Mexico and the southern United States. Most of the population is resident, but some northern birds migrate south to Mexico in winter. It is a bird of most wetlands, including ponds and rivers, and usually feeds by dabbling for plant food or grazing. It nests usually on a river bank, but not always particularly near water. The male has a nasal call, whereas the female has the very familiar "quack" commonly associated with ducks.