Wintering grounds of the European cranes
Where the European cranes overwinter depends on their breeding origin and their affiliation to the different flyways.
Birds from the west European flyway to which our native cranes belong, use wintering grounds in Spain, France and increasingly also in Germany. The main wintering grounds on the Iberian Peninsula lie in the Extremadura/Andulsia (up to 133,000 overwintering birds) in the south west and in the Laguna de Gallocanta (up to 84,000 cranes) in northeastern Spain. Smaller wintering places are located in the Laguna de La Janda (up to 2,000 birds) near Cadiz, La Sotonera north of Zaragoza in northeastern Spain as well as in the Laguna de Villadafila and near El Oso in northern Spain.
Important overwintering areas in France lie in the south of the Parc Naturel Regional of Gascogne and in the neighboring protected area Arjuzanx (max 59,000 cranes), in central France in the area of the Parc Naturel Regional de la Brenne, the L’Allier-river meadows south of Moulins and Nevers as well as in the north east of France around the reservoirs Lac du Der Chanteqoc (max 206,000 birds), in the Parc Naturel Regional de la Foret d´Órient (max 16,000) and at the Lachaussée (max 14,000).
In the recent years more and more cranes try to overwinter in Germany, whereby the number of overwintering birds varies greatly and in cases of long cold periods with harsh frosts and snow, many birds then fly in direction of France. The Diepholzer Moorniederung between Osnabrück and Bremen and the area around Berlin (Rhin-Havelluch, middle Havel between Potsdam and Brandenburg/Havel, Notte-lowlands south of Berlin) are areas in Germany that have developed into main wintering grounds, with possibly up to 5-10,000 cranes overwintering in each of the areas.
Birds of the Baltic-Hungarian flyway in mild winters already overwinter in small numbers in the Hortobagy in Eastern Hungary, which also is the most important autumn resting area with up to 135,000 cranes. Smaller wintering areas are also located on the northern Balkan, in northern Serbia, in Croatia and Bosnia-Herzegovina. Up to 20,000 birds of this route move on to overwinter in North Africa. Although the wintering area extends from here to Morocco in the West and to Libya in the east, the majority of cranes overwinter in different wetlands in Tunisia and neighboring Algeria.
In recent years, increasing numbers of cranes of this route were observed to leave the route leaving roosting sites in Hungary to the west and flying north of the Alps to wintering areas in France and Spain. Another part of the birds passes over northern Italy to the west, especially the south of France, to spend the winter in the Camargue.
From individual tagged birds it is even known that they continue to fly from North Africa to Spain and then return to their breeding home on the West European flyway. This leads to the assumption that the west European and Baltic-Hungarian flyways are not completely split from each other but that a certain exchange takes place between them.
Cranes which use the east European flyway migrate across the Black Sea on to resting areas in Turkey and Israel, where in the Hula valley in northern Israel ten thousands of birds partly already overwinter. A considerable part of the east European cranes migrate to wintering grounds to East Africa, where around 70,000 wintering cranes can be counted in Ethiopia. The Lake Tana works as the main wintering ground with up to 60,000 wintering birds.
Wintering grounds of the native breeding cranes
On the basis of recoveries of cranes that have been ringed and transmitted in Germany of the native breeding population the wintering grounds of the in Germany breeding cranes are very well known. The wintering grounds stretches across a large area of the western European flyway and contain breeding places in North- and Eastern Germany, France and Spain. In contrast to this, recoveries of German cranes are missing from Portugal and Morocco, which also belong to the wintering area of cranes from the western European flyway and where still a few thousand birds are found each. In the 1970ies Morocco was still an essential wintering area. Changes in landuse through increase of maize and rice fields, mild winters and better protection conditions at the resting places in Spain and France lead to a shift of the wintering to the north.
Ten thousands of cranes overwinter in different places in the Extremadura in Andalusia/Spain. There the birds often search for acorns of the holm- and cork oaks in the dehesas, the light Mediterranean oak forests. These traditionally used forests are the result of centuries of low-intensity land use. With their average 50 or 60 trees per hectare on pastureland or crops they remind of sprawling park landscapes. The cranes open the hard shells of the acorns with their beak and eat the bitter tasting fruit flesh. Next to these traditional feeding habitats many cranes nowadays use the intensive maize and rice fields in the area of Navalvillar de Pela to find food.
The Laguna de Gallocanta lies in the northeast of Spain, where the cranes spend the night in a flat salt lake on a high plain and search for food in the surrounding fields in the daytime. Smaller wintering areas are located in the Laguna de la Janda near Cadiz, La Sotonera north of Zaragoza in northeastern Spain as well as the Laguna de Villafafila and near El Oso in northern Spain.
Important wintering areas of the German breeding cranes are also located in the south and northeast and in central France.
In southern France the cranes especially use the Parc Naturel Regional of the Gascogne and the neighbouring nature reserve Arjuzanx. This region was formed by the open brown coal mining are and was recultivated in 1980. Nowadays the area is a 2,500 ha big fenced nature reserve with lakes, meadows and maize fields.
Wintering sites in Central France are located in the Parc Naturel Régional de la Brenne and in the flood plains of the river L’Allier south of Moulins and near Nevers. Due to missing reservoirs the cranes sleep in the backwaters and flooding areas of the L´Állier River.
The resting and wintering cranes in the northeast of France concentrate on the area of the big reservoir Lac du Der-Chantecoq, which was created in the 1970ies as a flood control basin. Apart from there, large numbers also overwinter at the adjacent reservoirs in the Parc naturel regional de la Forét d´Orient as well as the Lacaussee near the border to Luxembourg and the Saarland.
In addition, over the past decade also winter traditions have developed at various resting areas in Germany. Depending on the weather several thousand cranes overwinter in the Diepholzer Moorniederung and the region around Berlin. In both regions the intensive cultivation of maize with available stubble fields makes an overwintering possible. But also other smaller resting places can hold hundreds or sometimes even a few thousand birds in winter, so that in mild winters up to 20,000 cranes remain in Germany.
Based on findings of ringed and tracked cranes in Germany it was possible to find out, that the migratory behavior differs depending on breeding origin. The cranes in Northeast Brandenburg still have the strongest migratory behavior, which causes many birds to fly to France and Spain for the winter. Breeding cranes of southern Mecklenburg mainly overwinter in Central and Southern France, while birds from northern West Pomerania often just fly to the north of France and some already spend the winter in Germany. The least migratory behavior can be found in the breeding cranes of Lower Saxony, which often overwinter near the breeding areas.