The golden eagle is one of Switzerland’s biggest birds of prey, with a wing span which can go up to a little more than 2 meters (over 7 feet). It feeds mainly off ground-living birds and mammals, especially hares, marmots and foxes. They have excellent eyesight: it has been shown that they can see a hare at distance of one kilometer (more than half a mile). They also eat carrion – often the victims of avalanches.
They like to live in open and semi-open areas at a height of between 1,500 and 3,000 meters (5–10,000 feet), usually making their nests, or eyries, below the tree line, usually on rock ledges or, more rarely, in high trees. Each pair has several eyries.
Eagles pair for life, and each pair has a territory of between 50 and 100km2, (20–40 square miles) which they defend to the best of their ability, whereas immature birds rove throughout the Alps.
Switzerland is thought to have about 300 breeding pairs, living in the Alps and its foothills.They are expected to spread to the Jura – indeed, the first birds have already bred on the French side of the border. At one time these eagles occurred even in the Swiss plateau.
The golden eagle has been on the protected list in Switzerland since 1953.
The bearded vulture is a huge bird, with a wing span of 2.7 meters (nearly 9 feet) – even larger than a golden eagle. It takes its name from the black bristles hanging at the base of the beak. The plumage is unusual: wild birds instinctively change the colour of the feathers they are born with by bathing in iron-rich water. This turns the white of their neck and underparts to rufous. These parts remain white in captive birds.
Its diet is also unusual, mainly consisting of bleached bones. Thanks to its elastic throat, it can swallow whole anything up to the size of cattle vertebrae; bigger bones are carried off and dropped onto platforms of rock from a height of 50–80 meters (150–250 feet) until they break into manageable pieces. Bones are very nutritious, and since other animals cannot digest them the bearded vulture faces no competition for its food.
Just as unusual is the bird’s breeding behaviour. Bearded vultures do not breed only in pairs, but also in threesomes, consisting of two males and one female. Both males mate with the female, and all three look after the nest and stay together throughout the breeding season. The reason for this is not known, but one theory is that it is easier for two males to defend the nest. There is often competition for suitable nesting sites, and the bearded vulture frequently take over nests built by golden eagles.
The hen usually lays two eggs, which hatch about a week apart. The second chick is much smaller than the first, and the older bird soon kills it, as there would not be enough food for both. The second egg is a reserve, in case anything happens to the first.
The bearded vulture disappeared from the Alps around the end of the 19th century, as its food sources – deer and goats – became ever scarcer. It was also persecuted by farmers, who believed it took lambs, and even babies – a physical impossibility, since the vulture cannot lift anything so heavy.
Reintroduction started in the 1970s, according to a carefully elaborated long-term programme involving not only Switzerland, but also Austria, France, Germany and Italy, and using captive-bred birds. The first were released in Austria in 1986. In Switzerland the site chosen for release was in the area of the Swiss National Park in the south eastern canton of Graubünden.
The nutcracker plays a vital role in the life cycle of one of Switzerland’s favourite trees, the Arolla pine, also known as the cembra pine, a conifer which grows in the high mountain zones of the central Alps.
The bird is an avid collector of the pine seeds, which it takes away and hides for use over winter. It is well adapted to its task. It has a special pouch in its throat in which it can easily carry 40–60 seeds at any one time. In a good year it may collect up to 100,000 seeds, which it hides at the rate of about eight per cache. Its specially adapted beak enables it not only to prise the seed from the cone, but also to open the tough outer husk, which it does by putting each one on an “anvil” – often a tree stump – and striking them. It tests the seeds by shaking them, and only takes the good ones. It has an extraordinarily good memory for where it has put them and can find them again even under snow a meter (three feet) deep.
The nutcracker is essential for the reproduction of the Arolla pine. Although it eventually eats most of the seeds which it collects, those which it leaves have every chance to develop, since they are buried in ideal conditions about an inch below the surface, and the fact that they are hidden in small groups gives them better survival chances.
The black grouse is a very striking bird, with a fan-like tail, the outer feathers of which are about 25cm long (10 inches). It lives in high moorland, and is found in Switzerland around the top of the tree line.
In winter, when it is essential to save as much energy as possible, they make themselves a little lair by hollowing out the snow and then blocking the entrance with the snow they have scratched up. The principle is like the igloo, for snow is a good insulator: where the outside temperature may fall as low as –25 degrees celsius (–13 Fahrenheit), the temperature in the hole will be only around freezing point, and is further warmed by the bird's body. They stay there quietly, not only saving energy, but also protected from predators. They only emerge to find food. It is important not to disturb them at this time, for this will make them leave their holes. This sets up a vicious circle: once outside, their body temperature drops and they need more food. Hunting for food keeps them outside for longer, getting cold...
Their lairs are not their only adaptation for the cold winters. They also have feathers in places where most birds do not: over their nostrils, which slightly warms the air they breathe in, and over their toes, which gives their feet a broader surface area and stops them sinking into the snow. They also have an insulating layer of down, which works by trapping the air.
Despite their adaptations, the number of black grouse is falling.