It looks like we’ve got another snowy owl irruption on our hands.
No, that has nothing to do with volcanoes: an irruption is an irregular migration of birds to an area outside their normal habitat. In the case of snowy owls, that migration is taking them from their breeding grounds in the high arctic to the Northeast and Great Lakes region. Bird trackers have reportedly documented the appearance of 1,200 owls in these regions between November and January.
That number is bigger than usual, but still not much compared to the “mega-irruption” of the winter of 2013-2014, which brought a reported 8,000 snowy owls in the lower 48 during the same block of months. It was such a huge migration that owls were reported even as far down as Florida and Bermuda.
The prevailing theory - and I think it's pretty well accepted - was that in 2013, there was a big, big population of lemmings, which is one of the big foods of snowy owls and the primary food that snowies feed to their chicks. So when you get this big population explosion of lemmings as a food source, the snowies reproduce that much more so they reproduced a lot. [. . .] So a lot of those young birds had to go somewhere else to get food so they headed south.
In other words, lots of prey means lots of owl babies, which ultimately means that some birds need to go further afield to find adequate food sources.
Though 2015 isn’t expected to host another record-breaking irruption, there have been higher numbers of snowy owls spooted in the US than usual. The surge may also be due to a new boom in the bird’s population, which occurred in Nunavut in Northern Canada. According to an article on AllAboutBirds.org, researchers on one island found 2010’s 33 snowy owl nests replaced this year by 116.
To see if snowies have been spotted in your neck of the woods this winter, check out this map from Ebird.