White-headed Duck

The White-headed Duck is a small, dumpy diving duck of the stiff-tailed group, named for the spiky tail it often cocks upward like a wren of the water. A breeding male is unmistakable: gleaming white head, neat black crown, warm chestnut-grey body, and an extraordinary swollen bill in vivid sky blue, one of the most striking features of any duck in the Western Palearctic. It rides low in the water, dives constantly, and would almost always rather submerge than fly, pattering away only reluctantly on whirring wings.

Once found across the Mediterranean basin and deep into Central Asia, this species has collapsed to a fraction of its former numbers and now ranks among Europe's most threatened waterfowl. In southern Spain it teetered close to extinction in the 1970s before a determined recovery effort pulled it back. Its most unusual modern threat is genetic: the introduced North American Ruddy Duck readily interbreeds with it, and protecting the pure White-headed Duck gene pool has driven one of conservation's most controversial control campaigns.

Look for a rounded, low-floating diving duck with a big-headed, short-necked look and a stiff tail that is frequently held cocked at an angle. In breeding plumage the male's white head and bulbous blue bill are diagnostic and visible at long range. Females and immatures are far duskier, best told by a dark cap, a pale cheek crossed by a single dark line, and the same stocky, tail-cocking shape.

Male vs. female

The sexes are easy to separate in breeding plumage and trickier the rest of the year. From late winter into summer the male is spectacular: a clean white head set off by a black crown and nape, a rich chestnut-grey body, and that swollen bill flushing an intense cobalt to sky blue. Outside the breeding season the male's bill dulls to a leaden grey-blue and his head can show more dusky mottling, but he keeps the whiter face.

The female is altogether more subdued and consistent year-round: greyish-brown overall with a dark crown, a paler cheek crossed by one dark horizontal stripe, and a plain grey bill that is far less swollen. She is easy to overlook among other diving ducks until she cocks her stiff tail or dives with the same low, rolling action as the male.

Juveniles

Ducklings hatch a dark sooty-brown above with paler underparts and a hint of the adult's face pattern, already able to dive within a day or two of leaving the nest. Juveniles resemble adult females but are duller and more uniformly brown, with a less clearly marked cheek stripe and a smaller, greyer bill. Young males only gradually acquire the whiter head and the swollen, blue-tinged bill over their first winter, so a mixed group in autumn can show a confusing range of intermediate faces. At all ages the stocky build, big-headed look and cocked stiff tail give the species away.

The White-headed Duck is a famously quiet bird and is essentially silent away from the breeding grounds, so it is far more often seen than heard. There is no true song. During courtship the male performs a curious mechanical display rather than singing: he raises his stiff tail, tucks his bill down against an inflated neck and taps or rattles the bill against it, producing low, dry drumming and rattling sounds along with soft belching or piping notes.

Females are equally reserved, giving only occasional low quacks, grunts and soft calls, usually when tending ducklings or in mild alarm. Because vocalisations are so muted and infrequent, birders rely almost entirely on sight rather than sound to locate and identify this species.

The White-headed Duck has a broken, patchy range strung across the mid-latitudes of the Old World. In the west a small but recovered population breeds in southern Spain, centred on the wetlands of Andalusia, with scattered records elsewhere around the western Mediterranean and across North Africa in Algeria, Tunisia and Morocco. Farther east it breeds around Turkish lakes and through the steppe wetlands of Kazakhstan, Uzbekistan and neighbouring Central Asia, ranging east toward Mongolia and north-west China.

It favours shallow, well-vegetated fresh or brackish lakes with dense fringing reeds for cover and areas of open water deep enough for diving. The Spanish birds are largely resident, moving only locally between lakes as water levels change. Central Asian breeders are migratory, shifting south and west in autumn to milder wintering lakes, with important concentrations gathering on a handful of large water bodies in Turkey, Iran and around the Mediterranean.

White-headed Ducks feed mainly underwater, diving repeatedly to the beds of shallow lakes where they sift and filter through soft mud and submerged vegetation. Rather than upending like dabbling ducks, they disappear entirely, surfacing a little distance away after each dive. Their broad, specialised bill is well suited to straining tiny food items from ooze and water.

The diet is mixed and shifts with the seasons. Much of it is made up of the larvae and pupae of midges (chironomids) and other aquatic insects, along with small crustaceans, molluscs and other bottom-living invertebrates. They also take plant material, including the seeds, shoots and tubers of pondweeds and other water plants. Chironomid larvae are thought to be an especially important food, which helps explain the species' dependence on productive, insect-rich wetlands.

Nesting is closely tied to dense emergent cover. The female builds a well-hidden platform nest low among reeds, reedmace and other tall vegetation at the water's edge, sometimes taking over and adapting the old nest of a coot or other waterbird. The nest is bulky and anchored to standing stems just above the waterline, keeping the eggs concealed from predators and out of view from open water.

She lays a relatively small clutch, roughly five to ten eggs, but these are remarkably large and coarse-shelled for the size of the bird, among the biggest eggs relative to body size of any duck. The female incubates alone for around 25 days. The downy ducklings are highly precocial, able to swim and dive to feed themselves almost immediately after hatching, though they stay with the female for their first weeks.

This is not a backyard bird, so the real question is where and how to see one. The White-headed Duck is rare, localised and easily overlooked, but a handful of well-managed reserves offer reliable, close views if you visit at the right time and come prepared to scan patiently across open water.

• Head to Andalusia in southern Spain, the western stronghold; Laguna de Zoñar and other lagoons in the Cordoba area, plus wetlands near Malaga, are classic and comparatively accessible sites.
• In the east, large Turkish and Central Asian lakes hold breeding and wintering birds, though these are harder to reach and best visited with local guidance.
• Time your visit for late winter into spring, when males are in full breeding dress with vivid blue bills and are actively displaying and easier to identify.
• Bring a spotting scope, as birds often sit far out on open water among other diving ducks; the swollen bill and cocked tail are the giveaways at range.
• Scan the boundary between reedbeds and open water, where birds feed and loaf, and watch for the low, tail-cocking profile rather than the head colour alone.
• Visit protected reserves with hides and respect access rules, since disturbance at this endangered species' few remaining sites can be genuinely damaging.

• Ruddy Duck: Introduced North American stiff-tail that hybridizes with it; breeding male has white cheeks and a solid black cap rather than an all-white head
• Common Pochard: Another diving duck of similar lakes but larger and slimmer, with a reddish head, grey body and no cocked stiff tail