The severe winter has proven devastating for many bird species that chose to overwinter in Sweden, with statistics showing catastrophic mortality rates. According to data from Artportalen, the national species observation database, as many as 90 percent of all overwintering wrens may have died during the prolonged cold period. The statistics are based on reported observations of the bird during weeks 1-8 of this year.
Other species showing significant decreases in reported observations include robins, grey herons, nightjars, and goldcrests. The data, reported by Göteborgs-Posten, indicates a widespread impact on Sweden's bird population from the unusually long and cold winter.
The only reasonable explanation is that the birds have died.
Niklas Aronsson, an ornithologist and editor of the magazine Vår Fågelvärld, told GP: 'The only reasonable explanation is that the birds have died.' The findings highlight the vulnerability of bird populations to extreme weather conditions and the importance of monitoring systems like Artportalen for tracking environmental impacts on wildlife.