This new video from the Weather Channel must set a new record for cramming the most snowy owl myths and mistakes into less than two minutes. It’s hard to know where to start, but here are two doozies.
Far from mostly being skinny and starving, as the video claims, the vast majority of the owls that came south in this winter’s irruption — including virtually every one we’ve caught for banding or tagging — has been unusually fat and healthy. That’s typical of big irruption years, which are the product of a bountiful nesting season in the Arctic spurred by unusually large prey populations. The owl they show being checked by vets was hit a bus, not found starving.
Nor is this irruption a sign of climate change; such events have been documented since at least the 19th century. That’s not to say snowy owls and other high Arctic species (like ivory gulls, polar bears, walruses and many nesting shorebirds) aren’t at early risk from changing climate patterns — they definitely are. European scientists have suggested in a paper in Nature that changes in temperature and humidity in the Norwegian Arctic are behind the flattening out of lemming populations, which have failed to peak since 1994 — the kind of peak last summer in Quebec that produced this winter’s irruption. But there’s no obvious line between climate change and an irruption like this year’s.
Lemmings need a good cover of snow in the winter to avoid the predation of foxes and weasels. The lemming population grows the most rapidly during the winter period. Without a good cover of snow there is no lemming boom and without good numbers of lemmings Snowies won’t breed.
Here’s paper from 2012 that discusses the dynamics of lemming populations in hihg-arctic Greenland and how the lemming populations has crashed since 2008: http://rspb.royalsocietypublishing.org/content/early/2012/09/05/rspb.2012.1490.full