Why male ducks shed their feathers in midsummer

This July, colourful drakes are turning into inconspicuous birds: the moult is beginning. Due to a hormonal shift, drakes must now shed their feathers. Their vivid plumage simply falls away, leaving behind dull feathers in shades of grey and brown that resemble the camouflage colouring of the females. «The moult can best be observed in mallards: their iridescent, green-brown plumage suddenly looks dull,» says Eva Goris, press officer at the Deutsche Wildtier Stiftung (German Wildlife Foundation).

Almost flightless for three weeks

The «large moult» lasts up to three weeks. During this time, the otherwise self-assured drake becomes rather shy: «He retreats into the reeds instead of waddling around proudly. There he waits until his new feathers have grown back in a few weeks and he can show himself in full splendour again,» says Eva Goris. During the moult, birds are almost incapable of flight. This means they have no means of escape when danger threatens.

Why do birds lose their feathers?

Feathers are made — like hair and fingernails — of keratin, which becomes brittle over time. In particular, the wing and tail feathers of ducks need to be renewed. «It will take until around October for the drake’s colourful plumage to have fully grown back. Of course, female ducks also go through the moult; however, a few weeks later than the drakes, as their chick-rearing duties are then complete,» explains Goris.

Walkers should try not to startle birds during the moulting season. «Dogs must be kept on a leash to avoid stressing the flightless ducks,» advises Eva Goris. Water sports enthusiasts such as canoeists or rowing boat users should avoid dense reeds. More about wildlife and biodiversity.