Great Gray Owl: The Gray Ghost Of The North

At 5:15 Friday morning I was standing in our dimly-lit basement, sweeping water toward a pump. Out of the corner of my eye I saw movement to my left. Despite not having had any coffee yet, my eyes were not playing tricks on me. Out of the shadows emerged a round, furry gray ball. It was a rather large vole! Had it come inside to escape the flood waters or had it been wintering in our home? Whatever the reason, it showed no fear, first scurrying slowly past a stack of totes labeled Christmas decorations, then passing behind me and under a pallet.

Where is the Great Gray Owl when you need one?

Rarely seen in our neck of the woods, the Great Gray is North America’s biggest owl. Reaching a height of 33 inches and wing span that can top 5 feet, it rivals the Eurasian Eagle Owl and the Fish Owl as the world’s largest.  But looks can be misleading. A large head, long tail and fluffy feathers hide a body that actually weighs less than the Great Horned and Snowy Owl.  Physical characteristics aside, the Great Gray Owl loves to eat voles – or meadow mice as they are sometimes called. 

Once in a blue moon, maybe not that often, we are paid a visit by the “gray ghost” of the north. During those winters when its food supply becomes scarce, the Great Gray Owl (strix nebulosa) will temporarily relocate to more favorable climes, traveling as far south as the Great Lakes.

 The species name, nebulosa, is Latin for misty or foggy, and along with the Great Gray’s rarity, may be the reason it is sometimes referred to as the “phantom of the north.”     

For the most part a nocturnal raptor, the Great Gray will alter its hours in winter, hunting post sunrise and pre-sunset. At such times it may perch and wait for a meal or it may fly about in search of prey. The latter method requires extremely low flight, never more than a few feet above the ground. 

In the warmer months, the Great Gray has a variety of food sources including squirrels, weasels, chipmunks and mice. Ducks and grouse have also been included on their food group and in rare occurrences they have been known to take crows and even small hawks.

But it is the vole which the Great Gray is particularly fond of – particularly in winter.The vole is highly nocturnal in summer, but come winter it is active in the daytime. This may be a factor in the Great Gray Owl’s altered hunting hours during the coldest months of the year. One of the species method’s of hunting voles in winter is unique and worth mentioning.

Beneath the snow pack is a series of tiny tunnels through which voles scurry about. This network beneath the snow enables the furry rodents to access small trees and gnaw at the bark. (Have you ever wondered, after the snow melts in the spring, what happened to the bark at the base the maple saplings you planted?)  

Though the small mammals are out of sight, the Great Gray can still detect their presence. Every move made by the rodents, even beneath a thick blanket of snow, emits sound waves. With acute hearing, the Great Gray Owl is able to pick up the sound from a nearby perch. Its large, feathery facial discs act as receptors, reflecting the sound to the owl’s ears. Once honed in on its quarry beneath the snow, the Great Gray will descend on the targeted location. With talons clenched, it will smash into the snow pack, caving in the mini-tunnels below. Their travel network clogged, the voles become trapped. The owl then uses its feathered talons to sift through the snow, searching for its meal (as depicted in photo).               

Adult Great Gray Owls do fall victim to predation in their far north home range. They are on the hit list of Great Horned Owls, Northern Goshawks, marten, lynx and wolverine. But the biggest contributors to a decline in its numbers are logging operations and electrocution from power lines.