Where the cranes go (2)
A lake for man and for birds
After the cranes have flown over the Taunus region, the first large and important resting place for the animals is in the heart of the southern, so-called humid Champagne, at the Lac du Der-Chantecoq.
The approximately 48 square kilometre reservoir with its highly indented banks and a shoreline length of 77 kilometres is the largest artificial body of water in France and regulates the water flow of the Marne and the Seine. This function of the lake means that there are very different water levels throughout the year: During the winter, the lake fills up, preventing floods on the rivers, and the water level reaches its highest level in the spring. During the summer, a large proportion of the dammed water is released again to maintain the passability of the Marne and Seine. As a result, the lake usually has a very low water level in autumn, with sandbanks and mudflats emerging. The whole area then looks more like an estuary and provides a suitable and protected habitat for wading birds, many migratory birds and ornithological winter guests. And the area lies exactly on the western European migration route of the cranes - two reasons why the reservoir, which was flooded in 1974, was quickly accepted by the animals as a resting and increasingly also as a wintering site. In addition, a high diversity of species has now developed in the avifauna around the lake.
The number of resting cranes during the autumn migration to the south varies greatly and is naturally dependent on the weather. Typically, 50-80,000 cranes are at the lake at the same time in late October/early November; 2019 saw a peak of over 260,000 birds, while 2022 was again more typical (85,000). While some of the birds continue their long journey after a short stopover of just a few hours, many others prefer to stay there for weeks, provided they are not forced to fly on due to unfavourable weather conditions (snow, frost). For some years now, there has been a tendency - also fluctuating - for cranes to winter in larger numbers at Lac du Der (approx. 11,000 individuals in 2022, slightly declining compared to 2021). Despite all the fluctuations, the wintering trend for cranes throughout France has shown an increasing trend over the last 40 years:
(Quelle: La Grue Cendrée en France. Migration et hivernage Saison 2022-2023. LPO Champagne-Ardenne)
The lake has also been well received as a water sports and fishing paradise. The fact that people and animals alike can feel at home in the otherwise sparsely populated area is due to the fact that the lake has been divided into different utilisation zones and all "users" get their share. A smaller part is completely closed to humans and serves as a resting area for birds. Nevertheless, the dam walls, the dyke and numerous observation stations in the accessible area of the lake offer plenty of opportunities to admire the animals as individuals or in groups.
The landscape around the lake is characterised by a complex mosaic of forests (mostly deciduous or mixed forests with tall oak populations), which alternate with large cultivated areas and pastures. This provides a good basis for a rich food supply for cranes, which are particularly focussed on the remaining maize fields.
Champagne's strong agricultural character with its predominantly arable land ultimately gave the region its name, derived from / Champs / Campus / Field. The eponymous Der in Lac du Der comes from the Celtic word for oak, the most important tree for building houses and the typical half-timbered churches of the region. The western European half-timbered structure with narrow, high rafters (in contrast to the almost square half-timbered structure of central Europe) and the low roof pitch are striking. Chantecoq was one of the three flooded former villages located in what is now the lake area.
The picture gallery for Lac du Der can be found here.
Sources
La Grue Cendrée, LPO Champagne-Ardenne
Field Guide to the Birds of the Lac du Der, Bernard de WETTER