The Great Cormorant, or Corbeau de mer in old French, has not always been common on Lake Geneva. Originally from the tropics, it has colonised much colder areas, as far away as Greenland. A fish-eater, it is seen as a formidable competitor by fishermen, and its opportunism and shamelessness in front of their nets have not helped its reputation; it was persecuted throughout Europe, to the point of extinction in the 20th century. It was only at the end of the 1970s that it was protected at European level, which drastically increased its population. Initially wintering on the lake (i.e. migrating from northern Europe in autumn), the Great Cormorant has fallen in love with Lake Geneva, where it now resides all year round. In 2017, there were almost 600 pairs on Lake Geneva.
It's hard to miss this large black bird spreading its imposing wings after a day's fishing. Its black plumage has green, purple and bronze highlights as you approach. With its long hooked beak measuring over 6 centimetres, it is easily recognised by its proud appearance with its beak pointed skywards. In mating plumage, its head whitens around its emerald eyes, as do the tops of its thighs, which it proudly displays during its parades, while rhythmically raising and lowering its wings. Gregarious, it is generally seen in colonies on rocks, enjoying the warmth of the sun. But it is also a great sportsman, and can cover almost 200 kilometres a day.
Unlike most diving birds, the feathers of the Great Cormorant are only semi-permeable. This is why it spends part of its day with its wings spread apart, in order to dry itself. This characteristic, which could be perceived as a disadvantage, is not really so. In fact, it allows it to dive more comfortably in deep water, reducing the amount of air between its plumage and its skin. By reducing its buoyancy in this way, it is easier to manoeuvre in the water. The Great Cormorant swims deeper than other birds, reaching depths of up to 34 metres and staying there for almost a minute, which makes it an unrivalled fisherman.
Information taken from Lémanique n°109 " Cormoran, the eternal return "and theORCA production, The Great Cormorant.
Photo credit : Kai Taimsalu
