The mallard is a large and heavy looking duck. It has a long body and a long and broad bill. The male has a dark green head, a yellow bill, is mainly purple-brown on the breast and grey on the body. The female is mainly brown with an orange bill. It breeds in all parts of the UK in summer and winter, wherever there are suitable wetland habitats, although it is scarcer in upland areas. Mallards in the UK may be resident breeders or migrants - many of the birds that breed in Iceland and northern Europe spend the winter here.