Why winter is the best time to watch teal

Eurasian Teal are with us all year in small numbers, but winter transforms them. From October onwards, our resident birds are joined by thousands of immigrants from Iceland, Scandinavia and Russia. These newcomers settle on shallow lakes, flooded marshes, reservoirs and estuaries, often forming tight, restless flocks. As the days shorten, the drakes moult into their finest plumage: a chestnut head, a sweeping green eye patch and a neat grey body. For the birdwatcher, this is the season when teal are both most numerous and most identifiable. A winter walk along a marsh edge or estuary can produce a hundred teal in a single scan, and the challenge of picking out a drake from the brown huddle is one of the great pleasures of cold-weather birding.

Size, shape and jizz: the small duck advantage

The first thing to notice about a teal is its size. At 34–38 cm long, it is the smallest dabbling duck in Britain, noticeably smaller than a Mallard and daintier than a Wigeon. In the water it sits low and compact, with a short neck and a rounded head. The bill is small and neat, not the heavy shovel of a Shoveler or the long, sloping bill of a Pintail. When disturbed, teal explode from the water almost vertically, twisting and turning in tight, fast flocks. Their wingbeats are rapid and shallow, and they often look dark against the sky. That combination of small size, compact shape and explosive flight is your first clue. Even in a distant flock, look for the smallest ducks in the raft; they are usually teal.

Male Eurasian Teal: a head pattern you cannot miss

In winter plumage, the drake Eurasian Teal is a jewel. The head is rich chestnut, broken by a broad iridescent green patch that runs from the eye towards the nape. This patch is bordered by thin cream or white lines, which make it stand out even in dull light. The breast is a warm pinkish-buff, speckled with dark spots, and the flanks and back are finely vermiculated in grey. Along the side of the body, a horizontal white stripe separates the breast from the grey flanks. At the rear, look for a bold triangular patch of black and yellow-cream under the tail. The speculum, visible in flight, is green and black with a white trailing edge. In poor light, the green head patch can look dark, but the chestnut head and grey body remain distinctive. A drake teal in bright winter sunshine is one of the most handsome ducks on any British water.

Female Eurasian Teal: subtle, not impossible

The female is a mottled brown duck, and at first glance she can seem like a small, dark Mallard. Look closer, though, and several features separate her. She has a dark crown and a dark eye-stripe, but also a pale loral spot at the base of the bill, just in front of the eye. This spot is small but often surprisingly obvious on a close bird. Her bill is dark grey or black, not orange like a Mallard's. The body is finely mottled and scalloped in brown, buff and cream, with no bold white belly patch. In flight, she shows a green speculum with a white trailing edge, the same as the male. Her legs are greyish, and her overall shape is compact and short-necked. If you are unsure, watch her feed: teal dabble and upend in shallow water, often in tight groups, and the female's small size and quick, nervous movements soon give her away.

Telling teal from similar winter ducks

Several other dabbling ducks share the same winter wetlands, so it pays to know the key differences. Use this quick checklist when scanning a mixed flock:

• Female Wigeon: larger, with a rounded head and a pale blue-grey bill tipped with black. She has a white belly and no green speculum. Wigeon often graze on grass, while teal prefer shallow water.
• Female Gadwall: greyer overall, with a steeper forehead and a dark bill with orange sides. In flight, she shows a white speculum, not green.
• Female Shoveler: much larger, with an enormous spatulate bill. She has a blue-grey forewing in flight and a more front-heavy look.
• Female Mallard: larger, with an orange and brown bill, a blue speculum, and white edges to the tail. Mallards are common and familiar, so use them as a size reference.
• Garganey: a summer visitor, rare in winter. The female has a stronger face pattern, with a pale supercilium and dark crown, and a longer bill. If you see one in December, check carefully.

The male teal is unlikely to be confused with anything else, but the female can be trickier. Focus on size, the pale loral spot, the dark bill and the green speculum. With practice, she becomes as recognisable as the drake.

Fieldcraft: where and how to find them

Teal favour shallow, muddy edges, flooded grazing marshes, reedbed pools and estuary creeks. They are often found alongside Wigeon and Gadwall, but they tend to keep to the shallows and the cover of rushy banks. On estuaries, scan the upper mudflats and saltmarsh channels as the tide rises; teal gather there to roost and feed. On lakes and reservoirs, check the sheltered corners and the edges of islands. Early morning and late afternoon are best, when birds move between roosts and feeding areas. A decent pair of binoculars and a hide or a quiet bank are all you need. Listen too: the drake gives a distinctive, high-pitched piping whistle, often transcribed as a ringing "preep", while the female has a low, harsh quack. Once you tune in to that sound, you will find teal even before you see them.