Whooper swan

The whooper swan (Cygnus cygnus) is closely related to the North American trumpeter swan, but is native to northern Europe and Asia. Its wintering grounds include much of Europe but they breed in the subarctic, often migrating for hundreds of miles. 

In the British Isles the whooper swan is only seen as a winter visitor, with breeding being a very rare occurrence. It can be seen throughout Ireland and in southern and eastern Scotland and northern England, plus a few other limited locations. 

Appearance 

The whooper swan is similar in size to the mute swan, measuring between 145 and 160 centimetres (57-63 inches) in length. It has the same white plumage as the mute swan, and black legs, but there are several differences that can be noted to distinguish the two species. 

The head and neck differ in that the whooper swan’s neck is much straighter (as opposed to the typical S-shape of that of the mute swan) and the head is much more triangular in profile. The “forehead knob” of the mute swan is absent and the line from crown of head to end of bill is virtually straight. The bill of the adult whooper swan is black at the tip and yellow at the base. 

Behaviour 

The whooper swan flies with powerful wingbeats, the neck extended forwards, making a swishing sound that differs from the rhythmic throbbing of the mute swan’s flight. When swimming the whooper swan keeps its neck straight and bill horizontal. It feeds by immersing the head and neck in water and sometimes upends to take food from deeper water. On land, the whooper swan walks more easily than the mute swan, and indeed spends more time foraging on land. Whooper swans are often seen in groups. 

The call of the whooper swan is what gives it its name, being a series of loud whoops that are reminiscent of bugle calls, hence the name “trumpeter” given to the North American close relative. A recording of the call can be heard on the appropriate page of the RSPB website.

Breeding 

Breeding typically takes place in the subarctic tundra, on coastal waters, lakes and large rivers, preferred sites being those with abundant reed beds. Nests are built on islands or in swampy areas, consisting of a large mass of reeds and other vegetable matter, lined with down. 

The typical clutch is three to six eggs, laid in late May or June, with incubation delayed until after the last egg has been laid so that the chicks will hatch together. Incubation is done by the female whooper swan with the male standing guard nearby. The eggs hatch after 35-40 days, the cygnets being led to the water as soon as they are dry. 

Only one brood is raised in a season. 

Feeding 

Whooper swans feed almost exclusively on plant materials, including grass, although young birds will also take water insects and larvae. They have a liking for grain and potatoes, which can make them unpopular visitors on farms where those crops are grown. 

© John Welford