Defying wind and weather, bird watcher Christiaan Both sets out. Peering through binoculars, he spies on migratory birds that have settled in the Zuidlaardermeer from the bird hide. “These look thankfully healthy.”
Because good health in wild birds can no longer be taken for granted. Since the contagious bird flu variant H5N1 was introduced, not only poultry is affected, but wild birds are also victims. With major consequences.
“Last year, ten thousand sandwich terns died from the avian flu virus in the Wadden area alone. Twenty thousand pairs live in the Netherlands, which is one sixth of what occurs in Northwest Europe. So that is an enormous excess mortality,” Both concludes in the TV Drenthe program The State of Drenthe.
Scientists do not yet know exactly how the birds picked up that virus, but it is a fact that the consequences are extensive. “Terns breed in very dense colonies, where things are not very hygienic. If one large tern gets it, the virus can suddenly spread quickly.”
Sandwich terns can live up to 25 years. “In the 1950s and 1960s, sandwich terns have already declined in numbers due to the many poison discharges. Then there were only 500 pairs left. Now the number was finally back to the original level, but then they are hit by the avian flu virus. And it takes years before they can recover,” says Both.
Not only sandwich terns are hit hard, birds of prey are also victims. “This virus originated in the poultry sector and is now spreading all over the world. The wild birds are just not immune to the virus. They always had bird flu, but it was a non-pathogenic variant. This H5N1 variant is very contagious and very sickening.”
There are also known cases in which mammals have died from this bird flu virus. “Seals and foxes, for example. That’s because they ate sick birds,” Both explains.
Could it be that a human can also become infected with the H5N1 virus? “I’m not a virologist,” Both says. “What I do know is that researchers at Erasmus MC in Rotterdam have carried out tests on ferrets. This shows that only a few mutations are needed for the virus to pass from mammal to mammal. And then it is only a small step where the can go from person to person. I cannot estimate how great that danger is.”
Together with professor of Animal Ecology Christiaan Both, we take a look at the wild birds in the Zuidlaardermeer area. Watch the report below: