Nothing in nature stays the same. Nature is always in flux and is best described as being fluid and adaptive. Once you wrap your head around these simple truths, I believe answering some of nature’s questions becomes easier.

Every few years, a number of bird species such as Common Redpoll, Pine Siskin, Evening Grosbeak and others will move out of their normal winter ranges and move into other areas seeking food. This group of birds is often referred to as the “winter finches”. This mass movement of a group of birds is called an irruption.

The study of irruption behavior is difficult at best because researchers are dealing with an event that happens irregularly and difficult to predict. In addition, the birds are moving great distances making tracking them more difficult.

In the past we have associated the irruption of the winter finches due to a lack of food in their home range. These birds feed upon the seeds from conifer trees. We people are often looking for reasons behind every behavior we witness in nature and so the lack of food was a perfectly good explanation of the winter finch irruptive behavior.

So, it is natural to assume that irruptive behavior in other species of birds such as owls must also be triggered by a lack of food. We even went as far as saying that when lemmings over-populated they would all commit suicide by jumping off cliffs. This idea was perpetuated by a Disney movie production in 1958-59 entitled White Wilderness, that claimed that lemmings would kill themselves by jumping off cliffs into the ocean. In 1983 an investigation by a Canadian Broadcast company into this Disney movie found that it was all staged and the production team was pushing and throwing lemmings off a cliff. Disney didn’t start this myth, but they definitely amplified it by falsely depicting it. So, it was natural to link the decline in lemming populations to irruption behavior of their main predator, the Snowy Owl. We incorrectly assumed that irruption of the Snowy Owl was due to a lack of food, similar to the winter finches.

Today we understand more but still there is much unknown about irruptive behavior, especially in Snowy Owls. Research into the irruption of Snowy Owls finds that these birds are extremely healthy and well fed when they move out of their natural range into other locations. The current thought is that an abundance of food is allowing the Snowy Owl to reproduce in greater numbers and perhaps this is what triggers the irruptive movement. This is the exact opposite of what we assumed.

This winter in many northern states we are seeing an irruption of Great Gray Owls and also the Boreal Owl. Dozens of these birds are showing up in areas where they are not normally found. Of course, it is amazing to see these birds that we don’t normally see, and it tends to draw bird watchers and photographers from across the country to see them.

Studies on irruptive behavior of the Great Gray Owl and the Boreal Owl are few. So as usual, when there is a lack of information, we people tend to make up ideas and reasons to fill in the blanks. Despite most reports of Great Gray Owls and Boreal Owls that have come into wildlife rehab centers with injuries, mostly due to collisions with automobiles, for the most part these birds are in good physical condition and well fed. Despite these findings, the idea that birds have irrupted out of their normal range is still attributable to a lack of food. Something isn’t adding up here.

We often want to point to one specific reason, for an explanation for things in nature. In fact, it’s often many different reasons that add up to trigger a visible behavior, not just one thing like the shortage of food. We have learned in just the past 20 years that much of what we believe about bird behavior isn’t true, so we shouldn’t be so sure of ourselves when we make bold, vast and sweeting generalizations based on no personal knowledge. What is true is that old myths take many generations to die out and new scientific data is often ignored for decades. We seem to be slow to forget and reluctant to learn. Until next time…

Stan Tekiela is an author / naturalist and wildlife photographer who travels the U.S. to study and capture images of wildlife. He can be followed on www.Instagram.com, www.Facebook.com. He can be contacted via his web page at www.NatureSmart.com.