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"We're getting into the hard stuff": abnormal mortality of common cranes, the avian flu virus is early and virulent
France 3 Aquitaine
Written by
Camille Michelland and Guillaume Ployé
Published on
10/28/2025 at 11:59 AM
As cranes begin their winter migration from northern to southern Europe, this year they are carrying the avian flu virus with them. Several were found dead in the Landes region, contaminated. This massacre is indicative of the virus's early and global circulation.
They announce the arrival of winter. Common cranes have begun their migration from northern European countries to Spain. They often stop over or decide to spend the winter in the Southwest. There is one place they particularly covet: the Arjuzanx Nature Reserve in the Landes region, ideally located on their migration route. Here, they easily find food, between the wetlands and cornfields. The reserve is also an excellent resting place before continuing their journey further south.
Abnormal mortality
Every year during the winter, nearly 30,000 cranes pass through the Arjuzanx Nature Reserve, making it one of the most important migratory sites in Europe. But this year, the very first cranes arrived sick, contaminated by avian flu. "We have observed an abnormal mortality of cranes ," confides Sophie Laugareil, curator at the Arjuzanx Nature Reserve, in the Landes region.
"This year, cranes are particularly affected throughout Europe."
Sophie Laugareil
Curator at the Arjuzanx Nature Reserve
Further north, at Lac du Der in Champagne, another stopover for common cranes, cases of avian flu have already been reported. The Arjuzanx nature reserve was therefore expecting to see sick cranes arrive with the migration phenomenon. "We knew that the migratory corridor was affected, and we were no exception," Sophie Laugareil saddened.
As the migration of common cranes is just beginning, this massacre is not a good sign. "Cranes migrate in groups, which further encourages contamination and mass mortality ," explains Jean-Luc Guérin, a lecturer and researcher specializing in avian influenza.
While this mortality phenomenon is occurring everywhere in France, and can be impressive, it is not "a new phenomenon ," assures Jean-Luc Guérin. This has already been observed in seabirds, he explains. On the other hand, "common cranes are very large birds whose corpses are easily spotted compared to small birds," the researcher qualifies.
Revealing birds
Since October 17, the risk level for bird flu has risen from "moderate" to "high" in France, the highest level. The discovery of several outbreaks across the country has prompted health authorities to raise the level. "It's early for the season ," explains Jean-Luc Guérin.
Cases of bird flu among cranes have also prompted the government to raise the bar. "The fact that cranes are starting to become infected shows that the virus is already circulating intensely ," the bird flu specialist explains. "We can expect even higher mortality rates in the coming weeks ," he says.
According to the specialist, this phenomenon of avian flu among common cranes is revealing. "It shows that there is active circulation throughout Europe, with introductions into farms reported almost daily in France and Europe ," explains Jean-Luc Guérin.
"We must be extra vigilant in the coming weeks."
Jean-Luc Guérin
Teacher-researcher specializing in avian flu
"We're getting to the hard part," says Jean-Luc Guérin. While a vaccine against avian flu has existed for two years, it is only intended for farmed birds. Since common cranes are wild animals, it is not possible to vaccinate them. "The goal of the vaccine is to achieve territorial immunity to block transmission chains," explains Jean-Luc Guérin. He assures that the vaccine has proven its effectiveness even if "we cannot prevent a few outbreaks from occurring."
https://france3-regions.franceinfo....-aviaire-est-precoce-et-virulent-3240271.html