It is looking like this winter is shaping up to be the winter of the snowies, and I don’t mean the frozen white stuff that falls from the sky. Nope, I am referring to Snowy Owls (Nyctea scandiaca). Snowy Owls are an amazing species of owl that normally lives in the arctic regions of Canada and Alaska. Every now and then, let’s say every three to five years, a number of these owls show up in places like the upper Midwest, Pacific Northwest and along the eastern seaboard. This is one of those years. You see, this is not owl migration. No this is owl irruption.
There is a big difference between migration and irruption. Migration is a predictable or annual event in which the birds leave their home ranges at a predictable time, such as the end of summer, and move to warmer places, or at least less extreme climates. In spring they return. This is all very predictable. Every single year, right on cue, the migration happens. Irruption is not regular or annual. It occurs in irregular intervals and only now and then. It is very difficult to predict an irruption year, although many try to predict with varying amounts of accuracy.
A good example of migration are the warblers. These tiny songbirds leave their home ranges at the end of summer and migration down to central and south America. In spring they return. Just like clockwork. Birds such as the Snowy Owl, Great Gray Owl and Northern Hawk Owl are irruptive. Normally they don’t go anywhere. They stay in their home range. However, every so often they pick up and head out on a long distance journey.
So at this point you might be asking yourself a couple questions. First of all, how do you know if this is an irruptive year and what makes the birds do this behavior? First, it would be normal to have a few, and I mean just a few, Snowy Owls being reported across any given region in a given winter. This year, hundreds are being reported in the Upper Midwest alone. Other areas are also reporting large numbers of these large white birds. So, armed with this information, I would say it’s safe to say we are having an irruptive winter with Snowy Owls.
So why does this happen. Traditionally it has always been thought that an acute food shortage causes these movements. So in other words the normal food supply for the owl would be running low, crashed, and the owls would be starving and would leave their traditional areas in search of another food source. I remember back in the 60’s and 70’s the common belief is that Lemmings, a small arctic rodent, would commit mass suicide by all jumping off a cliff. This turned out to not be true on so many levels, starting with the fact there are very few cliffs of sufficient height in the arctic in which to jump. And besides, no wild animals have ever been documented to commit suicide. The drive to survive is way too strong.
Over the past few years, studies have shown that the lemmings populations in the arctic are at an all time high, so this wouldn’t support conventional thinking, would it? So what the current thinking is, due to the abundance of food supplies, the owls have been able to reproduce at record numbers. High population of owls has lead to a natural dispersal of birds out of their home range. This is a fairly common behavior for many of mothers natures critters. Exploring new opportunities is how some animals are so successful. Irruption is just one more way to fill a niche.
When these owls irrupt from their natural home range they don’t just go south. They also go east and west. We often think that the birds make a bee-line due south. Obviously not true. Many owls will end up along the west coast. I just was looking at some information of ten Snowy Owls together along the coast of Washington state. Many of these owls will end up along the east coast in places like New York.
Once established in a spot the owls often stay put for several months or at least to the end of winter when they will return back to their home range. Let’s hope the snowies survive winter and return safely home in spring thus completing the cycle. Until next time…
Stan Tekiela is an author / naturalist and wildlife photographer who travels the US to study and photograph wildlife. He can be followed at www.twitter.com, www.facebook.com/stantekiela or his web page at www.naturesmart.com