“On the coast, we have never observed such a hectare of wild birds. “ Terns, gulls, gulls, greylag geese … Pierre Thellier still can not get over it. This person in charge of the Platier d’Oye National Nature Reserve, in Nord-Pas-de-Calais, counts the corpses that have been collected since the beginning of the month. “Last week, we already counted 1,433 terns for a total of 1,671 birds, all species combinedHe testifies Science and the Future. Is it due to the heat wave? Not even. The culprit behind this massacre is none other than the H5N1 virus. It is known for its role in avian influenza, called by specialists “avian influenza”. This highly contagious viral disease affects domestic birds and wild birds. Since October 2021, it has killed no less than 383,000 wild birds worldwide, according to the World Organization for Animal Health. And the number is probably underestimated: Sick and dead birds are hard to track.
However, this bird flu epidemic is not the first that seabirds have been exposed to. ““It could happen from time to time that a duck or a swan was contaminated, but it remained quite anecdotal, and it was always during the winter.” Note Pierre Thellier. But this year, the bird flu lasted much longer than usual until the spring and summer period. However, spring and summer correspond to the reproduction period in birds. It is therefore a time when individuals are very close to each other. Problem: simple contact with an individual infected with H5N1 virus is enough to infect another individual. “It is catastrophic as the individuals are in colonies and living in promiscuity. The transmission of the virus is therefore very strong. From the moment you have a few sick individuals, the virus will only spread between the birds. We are witnessing a real epidemic of bird flu “, alert the reserve manager. To limit the spread of the virus, the project manager and his team sent as many corpses as possible for destruction (slaughter of animals unfit for human consumption). But they could not do much more.
A unique phenomenon
France is not the only country affected: “en Belgium is also a disasterSays the project manager. The virus has also killed cranes in Israel, Dalmatian pelicans in Greece and gannets in Canada and the United Kingdom. And it does not get better: “we are soon entering the migration period after the wedding, and infected birds from the north are at risk of infecting birds from the south. “.
For the Royal Society for the Protection of Birds (RSPB), the largest animal protection organization in Europe, it would be the worst outbreak of bird flu ever recorded. In previous years, H5N1 outbreaks remained localized. But this year, the disease is spreading like wildfire. The World Organization for Animal Health also notes that the phenomenon is unusual in terms of mortality, the number of species affected and the diversity of the geographical areas affected.
Still, the virus is not new.