A preliminary red list from SLU proposes classifying the snowy owl and barn owl as nationally extinct in Sweden. The last known breedings occurred in 2015 and 2003 respectively, with a shortage of small rodents believed to be the cause of the decline. Experts point to climate change as a contributing factor to the crashed rodent cycle.
Sweden's Agricultural University (SLU) updates its red list of threatened species every five years. The next official version is due in spring, but a preliminary list for birds was recently published. It proposes classifying both the snowy owl (Bubo scandiacus) and barn owl (Tyto alba) as nationally extinct. The last confirmed breedings for the snowy owl were in 2015 and for the barn owl in 2003.
Already, over 200 species are considered nationally extinct in Sweden, mostly insects, vascular plants, mosses, and lichens. Among mammals are wild reindeer and black rat, along with eight other bird species. Pearl owl and hawk owl are new to the red list.
Mikael Svensson, a biologist at SLU Artdatabanken, calls the snowy owl a flagship species: “The snowy owl is of course a flagship species. Everyone has probably seen Harry Potter.” He notes the decline in owls is surprising: “It's a bit of a surprising outcome that things look bad for so many owls. It's going badly for pearl owls too, so something is happening at night, one could say.”
The issue for the snowy owl is the lack of small rodents. Traditional lemming years, with peaks every four years, have crashed since the early 1980s. “It has affected the snowy owl and other birds of prey in the mountains enormously,” says Svensson. Climate change is suspected of disrupting the snow cover, creating ice crusts that prevent rodents from building tunnel systems.
Owl expert Berth-Ove Lindström is cautiously optimistic. He has witnessed snowy owl breedings in 1978, 1982, and 2015, all during good lemming years. “If the number of mountain lemmings increases, it can return,” he says. Icy winters with rain worsen living conditions for the mountain lemming, impacting species like rough-legged buzzards, arctic foxes, and gyrfalcons. Snowy owls can travel up to 5,600 miles per year, from the Nordic region to Canada or Alaska, and could therefore return under better conditions.
National extinction does not mean global: snowy owls remain in Norway, albeit in poor condition.