Synthèse de la migration des Grues cendrées 2008/09 : l'hivernage

Total numbers for the 2008/2009 wintering in France amounted to about 81,600 cranes, the highest on record. The previous record goes back to January 2001 with close on 68,000 birds. Wintering was on a sharp increase compared to last year (57,400 birds). Two factors combine to explain the situation. In the first place, an increase in crane numbers over the past fifteen years has necessarily increased numbers wintering in France. Secondly, bad weather (heavy snowfalls and icy conditions) forced the birds to leave Germany, where they normally overwinter, and relocate to France where milder weather prevailed.

The 2008/2009 wintering was marked by a violent storm, ‘Klaus’, which reached the coasts of the Gironde and the Landes at 0500hrs on January 24^th. Gusts of over 170kms per hour were recorded on the coast and 130kms per hour inland. When the storm struck, the cranes were still on their dormitory sites. The Arjunzanx site was particularly badly hit. Hundreds of conifers were blown down. For several days after the storm, there were few birds left on the site, compared to the 23^rd, when there were about 20,000. Subsequently, the almost total absence of the birds on the site can be explained by the fact that they sought refuge in some nearby fields which had been flooded. At all events, this storm caused considerable disturbance to the cranes.

Lorraine

Despite a prolonged period of extremely cold weather, several sites were still occupied in mid-January, principally in the Meuse: 2,200 birds remained close to the Reine forest and at least 192 were counted on the Lachaussée site on January 19^th. At the same time, birds were also observed in the Argonne on several occasions (max. 87) and in the Meuse valley near Mouzay (max. 58). In the Moselle, to the east of the region, at least 70 cranes were seen on the ponds on the Lindre estate. However, sites in the vicinity of Billy-le-Grand -Etain (55) seemed deserted in mid-January, although 180 cranes were observed at the beginning of February as was the case near Toul (54) where about one hundred birds were seen.

Isolated individuals were also noted to the north of the Moselle and in the Vosges department, as well as several small flights near Nancy (54).

Numbers wintering in the Lorraine this season attained a new record of close on 2,900 cranes.

Champagne-Ardenne	The wintering bird record was broken this season with 21,500 cranes recorded during the international bird count which took place on January 17^th and 18^th (the previous record being 19,725 birds in January 2008). The Der lake (51/52) and surrounding ponds were host to 16,200 cranes, 2,750 birds wintered in the Argonne (in Champagne) and 1,970 on the Horre pond (51/52). Just over 500 birds spent the winter on the Aube lakes. About 10 cranes were counted in the Ardennes.

Central France	The 2008 - 2009 season broke all records for wintering sites in central France. As early as September 28^th, cranes were seen on two sites. However, numbers remained surprisingly low until November 3^rd, when large groups were observed on a local basis such as the 4,000 cranes on a site in the Creuse, which at present is used as a migratory stop-over but could eventually become a wintering site in the fairly near future. As a result of the arrival of large flocks of birds, numbers on the migratory stop-over exceeded 8,000 on November 18^th and 7,000 on the 22^nd as well as up to 900 in the Allier, 1,200 in the Cher, 4,000 in the Creuse, 200 in the Indre and 4,000 in the Nièvre. In fact, these large numbers made up the ‘advance guard’ for record-breaking wintering in central France. By mid-January 2008, numbers had reached a record 9,070 cranes. A break-down of numbers on the 10 sites is as follows: 846 on the Allier site, 5,112 on the 4 sites in the Cher (respectively: 3,495, 1,059, 540 and 18), 1,220 on the Indre site and 1,891 on the 4 sites in the Nièvre (respectively, 1,314, 354, 190 and 30). This winter, a significant ‘turnover’ was observed. From February 19^th, large numbers of cranes left the sites in the Nièvre and those in the Cher from the 25^th. There were only a few hundred birds left in March (less than 250 by mid-March), only 8 in the Nièvre on April 4^th and 4 in the Cher on the 5^th, these dates corresponding approximately to the end of the wintering period.
Aquitaine	This year, the number of cranes wintering in Aquitaine was extremely high, reaching second place behind that of 2001/2002 which stood at 50,000. For the 2008/2009 season, close on 46,000 cranes wintered in this region. Counts were carried out between January 10^th and 15^th. The main wintering sites were once again Captieux (33/40) and Arjunzanx (40) with respectively 21,600 and 19,100 birds. The Cousseau Pond Nature Reserve was host to 1,140 cranes and 2,500 birds were counted on the marshes and lagoons in the Landes. We have no records for the Lugos-Ychoux (33) and the Saint-Martin-de-Seignanx (40) sites, so an estimation has been made.
Other régions	Apart from the four previously-mentioned regions, other sites were host to wintering cranes. In the Hautes-Pyrénées, 1,100 cranes were counted on the Puydarrieux lake in mid-January. On January 19^th, 764 cranes were seen in Petite Camargue (30) and 61 in the neighbouring department of the Bouches-du-Rhône. The total number for this area amounts to 825 birds. About 180 cranes wintered in the Aiguillon Bay (85) and in the Ain, 2 birds were recorded between January 14^th and 21^st, while 8 cranes were seen on the aerodrome at Calvi in Corsica.