Goosanders or Common Mergansers Mergus merganser swimming on the River Derwent 

Goosanders or Common Mergansers Mergus merganser are sawbill ducks that feed on fish and invertebrates including crustaceans. A small number of these birds may be found overwintering on the River Derwent in the centre of urban Derby, and the drakes in particular certainly stand out as their breeding plumage is so striking. Their heads are a dark bottle-green, although the feathers appear to be black in poor light, and when in full breeding condition, the males also have a pink flush on their white breast feathers. Sawbills possess long, thin and serrated bills, enabling them to deal with slippery prey.

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