Gadwall

The gadwall (Anas strepera) is a dabbling duck that is less commonly seen in the British Isles than in Eastern Europe. The resident British population, mainly in southern and eastern England and south-east Wales, is augmented by winter migrants from the continent, and wintering birds are also found in south-west England and Ireland.

Appearance

It is smaller than the mallard, with male gadwalls being around 51 centimetres (20 inches) long and the females a few centimetres shorter in length. It is mainly grey in colour, apart from a white belly, with the females being slightly browner in plumage. When seen up close, it is apparent that the grey colouring consists of fine barring and speckling. Male gadwalls are noticeably darker towards the rear. The bill is small, with orange sides. The male’s head and neck are grey-brown, speckled with black, and the female has more brown in this area, with coarser markings.

Behaviour

In flight, the gadwall beats its pointed wings quickly, showing a white wing patch as it does so. In the water it floats higher than some other duck species, either in pairs or small groups. Male gadwalls will croak and whistle, whereas the females quack and chatter.

Breeding

Gadwalls return to their breeding grounds in late March or April, having left them the preceding autumn (September to November). Although the birds arrive in pairs, a courtship display often takes place in which the females may be surrounded by several males. There is no guarantee that she will stick with her original choice.

The breeding grounds are mainly inland bodies of still water, such as lakes and gravel pits, surrounded by thick vegetation. The nest is generally well concealed in the grass, close to the water or on a small islet. It will be lined with dry vegetation.

A clutch of anything from seven to twelve eggs will be laid in May or June, and these will be incubated by the female alone for up to 27 days. The chicks will be led to the water very soon after hatching, although it will be seven weeks before they fledge. They will roam the surrounding countryside until it is time to leave for winter quarters.

The diet of young gadwalls includes a wide range of insects and molluscs found on the water surface or just below. However, as they get older, gadwalls become almost entirely vegetarian, with water-plants and seeds forming their diet.

Conservation

With fewer than a thousand breeding pairs in the whole United Kingdom, the gadwall is on the amber list of bird species with an uncertain future. Birdwatchers are much more likely to see wintering gadwalls, many of which reside on coastal wetlands at this time.

© John Welford