Among the wrens, as many as 90 percent of all overwintering individuals may have died during the long winter, according to statistics from the Species Portal on reported observations of the species during weeks 1–8 of this year.
A sharp decrease in the number of reported observations is also visible for the robin, the grey heron, the great black grouse and the kingfisher.
"The only reasonable explanation is that the birds have died," says Niklas Aronsson, ornithologist and editor of the magazine Vår Fågelvärld, to GP.
