Best time to see: all year

Key facts

Handsome chestnut-headed diving duck, seen in large flocks in winter and in small numbers on park lakes

Essex has an important breeding population, around reservoirs and lakes on grazing marshes and gravel pits

Many immigrants from Siberia and N. Europe arrive in winter

Recognition

Male: rusty head, grey body with black breast and rear end; female duller, mainly brown; 45 cm

Feeds on aquatic plants by diving from the surface, sometimes in large flocks; rarely walk on land

Patter across water to take off; flight strong and powerful, often in tight formation

Lifecycle

Nest is a mound of vegetation lined with down, at or near water's edge

One brood of 6-11 greenish eggs, April–May

Female alone incubates and also tends the ducklings, which swim soon after hatching