Mike could hardly believe his eyes as he stalked as close as he dared to the apparition on the stony beach. If you are persistent and patient, long hours of searching sometimes pay off in unexpected moments. Mike settled into position and began taking shots he had hardly imagined would come his way.

The focus of Mike’s attention was a rare visitor to Maine, a thrilling sight for any serious birder and a photographer’s dream. The Great Gray Owl (Strix nebulosa) is one of the most sought-after birds of the northern boreal and montane forests, normally found only in high latitude locations around the globe. Considered the tallest owl worldwide, its enormous head, massive facial disk and striking plumage make it instantly recognizable to those who seek to identify the great owls of wild areas. One of 260 owl species now recognized globally, this bird shares traits with its cousins including superb hearing and eyesight, and soft feathers adapted for silence in flight.

Standing nearly three feet tall at maturity, with a wing span of five feet, this owl cuts a memorable figure if you are lucky enough to spot one. Their striking feathers are a mix of silver, gray and brown with fine barring and a unique white “bow tie” or “necklace” on the neck. The feathers provide excellent camouflage against the bark of large trees for a bird that may sit motionless for hours on end. The long tail is helpful when maneuvering in heavy cover or in handling strong winds. I have read accounts of scientists going days without seeing an owl even when hunting in known nesting areas.

These owls live around the globe in the upper reaches of the Northern Hemisphere, with the forests of northern Canada and Alaska prime habitat along with scattered populations in California, Washington, Oregon, Idaho, and Wyoming. The birds frequent boreal spruce and fir habitat and mid-elevation montane regions, using meadows, bogs, and clearings for hunting. Such habitat is not conducive to tourism so the most likely opportunity for those of us living in places like Maine to spot these owls is when they are forced to migrate south in harsh winters in search of food, the same irruptions that bring Snowy Owls to our shores in some years.

Sightings of Great Great Owls are unusual in Maine since the birds have never been confirmed to breed within the state. With milder winters becoming the norm in the last couple decades it may be that irruptions of the owls from northern boreal areas to Maine will become even more unusual. From a search of birding records, it appears the last report of owls in Maine occurred near Houlton, Aroostook County in October through December 2022.  This makes Mike’s good fortune in filming his owl a very lucky day.

Great Gray Owls are not nest builders so they seek out broken-topped trees or large tree cavities to set up house-keeping. They have also been observed repurposing large stick nests built by other raptors, and on occasion the birds will make use of artificial nesting platforms. Given the severity of winters at northern locations, the owls wait until March through May for nesting, with the larger female laying between two and five eggs, with some variability dependent upon the availability of food locally. The female does most of the incubation over a period up to 36 days, sitting the nest nearly 24 hours daily, and she handles much of the chick care over the six-week period until fledging.

The male is actively involved with his focus on hunting for food and assistance in defending the nest from intruders. In the excellent book “What An Owl Knows” by Jennifer Ackerman, I found reference to these owls (and some other owl species) experiencing “asynchronous hatching” where the eggs may hatch at wide intervals to increase the chances of one or more chicks surviving to adulthood. The author also noted that males have been observed spreading their wings over a sitting female during rainy weather. It is not surprising that the adult owls may lose one third of their weight during the rearing process. In the worst cases, when adults are overly stressed or food availability is inadequate, they may abandon chicks to ensure their own survival to breed another year.

These owls are highly adapted for hunting small mammals, including at night when their vision is superb including the ability to detect ultraviolet light.  While Snowy Owls are focused on lemmings, Great Grays target mostly voles, thereby limiting competition between the two species. When voles become scarce the owls will switch to similar-sized species like lemmings, pocket gophers, shrews, and mice. They have also been observed snatching squirrels, rabbits, amphibians, and smaller birds. It takes as many as seven voles each day to keep an adult owl in top condition so you can imagine the hunting challenge for a male feeding his mate and several growing owlets.  Males are determined hunters, bringing as much food to the nest as possible even if he ends up with numerous prey animals stacked up and waiting for ravenous chicks to awake. As with other predators of small mammals, the population of owls moves up and down in line with the cycles of their prey.

Great Gray Owls are well known for their ability to plunge into snow in search of prey, sometimes driving their sharp talons up to two feet deep. Scientists are still learning how the owls manage to locate prey under deep snow, even in the windy conditions that often exist in winter. The large facial disc is certainly a factor because the owls gain the benefit of sounds “collected” by those feathers arrayed in an oval shape around their face. Like other owls, the ears are asymmetric, offset so that sounds arrive at each ear at slightly different times, allowing the owls to triangulate the source with great accuracy.

When hunting, these owls will sit on elevated perches for extended periods using their keen eyesight and ears to locate nearby prey. Their wings are shaped and feathered in such a manner as to allow nearly silent flight to a location above the target.  Then the owls go into a hover directly above the target in what scientists believe is the final calibration step before crashing into the snow in hopes of snatching a meal.  Despite the known sound dampening effect of snow, it appears that certain wave lengths of sound from tiny voles are transmitted through the snow at levels sufficient for the owls to zero in for the kill. Recognizing that the owls must be careful to expend less energy in hunting than they gain through successful attempts, their ability to snag food even in challenging circumstances is remarkable.

The primary vulnerability of Great Gray Owls is at the egg and nestling stage, when raptors, martens, or raccoons may raid the nest. Adult owls are safe from all but the largest raptors like bald or golden eagles. Scientists have documented some risk to the birds from mosquito-transmitted West Nile virus.  The larger threats to the owls are from mankind, thanks to pollution, habitat loss, rodenticides, and vehicle collisions. Conservation efforts when they exist are generally focused on protecting breeding and nesting habitats from excessive logging, and the erection of nest platforms if natural nest sites are lacking.

Population estimates for this owl are hard to come by because of their boreal distribution and remote lifestyles but they are currently assessed as a Species of Least Concern by the IUCN. Partners in Flight estimates the North American population as somewhere between 50,000 and 100,000 birds. While the owls may be in reasonable shape overall, scattered populations in remote locations may be more vulnerable and I wonder about the safety of the birds in places like Siberia where poaching is still endemic.

As with other elusive raptors, Great Gray Owls have long inspired myths and legends, with people endowing the birds with great wisdom, foresight, or patience. Some indigenous people view the owls as messengers and spirit guides, or as protectors of the fragile boreal forests. These beliefs have inspired vernacular names such as “Spector Owl” or Phantom of the North.”

Whether or not you believe these magnificent owls are a bridge to another dimension, they clearly serve as ambassadors for those of us in developed areas to become more attuned to the fragile balance of nature in boreal habitats. These silent hunters serve as an inspiration to naturalists, artists, and photographers, triggering us to learn more about the birds and their quiet haunts.

If you like Ed Robinson’s writing, check out his two Nature Notes books! Click here for more information.