May be harder to predict irruption of northern owls

For at least the past several decades you could forecast the irruption of northern or boreal forest owls with some reliability.  For instance, great gray owls tended to irrupt into southern areas of Ontario and Quebec every 4 years and sometimes 5.  Usually a great gray owl irruption was accompanied by both northern hawk owls and boreal owls.  However things seem to be a bit all over the map these days.  Recent research and surveys conducted in the artic and sub-artic and boreal forests seem to point to a possible  culprit, the less predictable weather patterns makes these cycles now harder to predict.  

Project SNOWstorm has posted an article on the less cyclical nature of of the lemming and other northern small mammal species such as voles and hares that serve as food for northern owls.  .

Excerpt.
That’s why reports in recent years from across the global Arctic and subarctic that the timing of such cycles has been changing, or that the lemming cycles have collapsed altogether, has been very worrying.


[font=Lato, sans-serif]An Important New Study on Lemming Cycles[/font]