By Tom Spears, Ottawa Citizen, December 19, 2018
Snowy owls have again flown south in large numbers to Eastern Ontario, and now birders are starting to think of this previously rare pattern as the new normal for the Arctic birds.
They’re also coming up with a theory: The owls are being driven south not because the Arctic is too harsh, but because it is no longer harsh enough. In an odd way, this may make life harder for owls in the North.
This is the sixth straight year of “irruptions,” or abnormal movements, of a lot of the big, powerful white owls. Normally they stay in the Arctic year-round, but young adults especially tend to move south if there is a shortage of food in the North.
This often happens when owls have had a good breeding season. It’s not that food itself runs short, but rather a case of having too many owls hunting in the same area.
https://ottawacitizen.com/news/local-news/snowy-owl-invasion-is-the-arctic-no-longer-arctic-enough