Population and distribution
The only native crane species in north- and Western Europe is the Common- or Eurasian crane. Its closed breeding area reaches from northwestern Germany via Scandinavia, the Baltic, Poland, the Ukraine, Belarus and Russia to Asia. Several isolated populations can also be found in England, the Netherlands and in France.
Around 113.000 to 185.000 crane couples breed in Europe, thereof 85.000 to 140.000 in the European Union States. Most of them live in Scandinavia (21.000 – 39.000 in Sweden, 23.000 – 50.000 in Finland and 1.500 -2.500 in Norway), in Poland (20.000 – 22.000), in the Baltic (7.000 – 8.000 in Estonia, 5.000 – 10.500 in Lithuania) and in the European part of Russia (25.000 -40.000).
Germany is the breeding home to over 9,250 of which around 4,250 couples breed in Mecklenburg- West Pomerania and 2.600 breed in Brandenburg. Smaller numbers of breeding pairs exist in Lower Saxony, Schleswig-Holstein and Hamburg, Saxony-Anhalt and Saxony. In the last few years single couples have also started breeding in North Rhine-Westphalia, Thuringia and Bavaria.
The dance of the cranes
From around mid-February the native cranes return to the breeding areas from their wintering grounds. The birds from the Scandinavian and eastern European countries, where it is still colder, fly over their usually already breeding conspecifics in Germany on their spring migration.
Until the breeding begins in March (the beginning of April) the couples reside on their feeding grounds close to the breeding territory. In the early morning one can often watch the fantastic dances of the cranes. They are expressions of inner excitement and can also be seen in the resting areas during the spring migration. The varied dancing figures are characterized through jumps, wing flapping, zigzag runs and running in circles. Thereby parts of plants and stones are tossed in the air.
The actual courtship takes place near the breeding area and is intended to prepare the partners for another and for mating.
Diversity of breeding places and nest locations
Peatlands and swamps forests, silted-up lakes and ponds are locations that cranes particularly like to use for breeding. The most common breeding place type in Germany is the alder swamp (wet to swampy alder forest). Small, water-filled kettle holes in the agricultural landscape are also used.
Being ground breeders cranes are especially exposed to danger. They have to protect their clutch and young from natural enemies like foxes, wild boar but also from humans. They therefore build their nests in knee-deep water. Depending on the substrate and water level the nests are piled up with plant material with a diameter of up to a meter. Occasionally small islands or alder root areas are chosen to breed on.
Breeding and rearing of the young
Central European cranes begin laying eggs in mid-March or at the beginning of April. The female bird usually lays two eggs in a time lag of one to three days. Both partners sit on the eggs for a period of 30 to 31 days. The young typically hatch within a day of each other. They are precocial birds and already follow their parents to forage within 24 to 30 hours after birth. Until the chicks can find food by themselves the parents pass insects, larvae, worms and snails to them with their beak for the first weeks.
The young grow quickly and are capable of flight after around ten weeks. By the end of July they can follow their parents to more distant foraging- and gathering places.
Protection measures for breeding cranes
A sufficient water level and a quiet breeding place offer the best protection for the brood and the rearing of the young. Low water enables wild boar and foxes to reach the nest unhindered and steal the eggs. In some cases even sleeping cranes have been killed and eaten by foxes. Wetlands are vital for the crane. Humans can help to create better conditions by building small dams or other regulation procedures if water levels are too low.
Since cranes are very sensitive during breeding and can easily give up their nest, human disturbances (forestry, agriculture, hunting Tourism) can be dangerous.
In Mecklenburg-West Pomerania and Brandenburg for example these dangers have been reduced through legal regulations for nest protection zones (up to 300 m). The dedicated work of many breeding site supervisors of Crane Conservation Germany and the numerous regional programs of full-time and voluntary nature conservation associations for the protection of wetlands help to enforce various protective measures on site.
Essential for the effective protection is a trustful cooperation of landowners, foresters, farmers and hunters as well as the staff of the regulatory and voluntary nature conservation.