Boreal Owl Guide (Aegolius funereus)

Latest posts by Richelle Tieman (see all)

Have you read the Guardians of Ga’Hoole series? If you have, you know that Grimble was a Boreal Owl. Another book, The Boreal Owl Murder, by Jan Dunlop, is based on birders tracking the Boreal Owl. This Owl is very scarce and isn’t seen often, so seeing one and getting a picture of it are covetous events in birdwatching circles. I happen to think that the vivid colors and spotting on this owl would manifest into a beautiful plushie toy that you could cuddle tight!

Don’t the eyes look a little glassy to you? The wispy feathers are begging to be pet, but stay away from those sharp, black claws! This is one owl that prefers to be left alone in heavily wooded remote areas and is unsociable. You could dress it up, but you can’t take it out!

Bottom Line Up Front

I’ve created this handy table for you to scan and get a quick synopsis of this fluttering, feathery anomaly.

Boreal Owls

Home Higher elevation coniferous and deciduous forests from Alaska to New Mexico and Northern Europe and Asia
Migrates Occasionally Migratory as far south as New Mexico
Mating Seasonally monogamous
Size and Weight Up to 11 inches tall and weighs 4 – 7 ounces
Defining feature Large black-rimmed white facial discs
Body Brown with white dots
Chest and Underparts White with brown streaks and white underparts
Head Large, rectangular, boxy, and brown with many tiny white dots
Eyes and Beak Bright yellow eyes, whitish-yellow beak
Status Uncommon but not endangered
Vulnerable Prey for Pine Martens, Hawks, and larger owls
Pellets Thick and grey (10mm x 20mm)

Most Commonly Confused With:

Northern Saw-Whet Owl

Northern Saw-whet Owl
Northern Saw-Whet Owl

The Boreal Owl is often mistakenly identified as a Northern Saw-Whet Owl. When looking for small owls, the Northern Saw-Whet is at the top of the list, and the huge round yellow eyes and white spotting look similar to the Boreal Owl. The primary differences lie in the size and facial features, with the Saw-Whet being only 6″ to 8″ tall and lacking the black outlined discs around the face.

The Boreal Owl will look like it has a furry hood over its head, while the Saw-Whet won’t.

 

Differences

  Northern Saw-Whet Owl

Boreal Owl

Beak/Bill

Black Pale yellow

Crown/Forehead

Streaks instead of spots

Gray shade with fine spots

Face No obvious dark hood frame Obvious black/dark brown hood frame

Size

6-8 inches

8-11 inches

types of owls
Boreal Owl

Other Names for the Boreal Owl

Tengmalm’s Owl

Named in honor of Peter Gustav Tengmalm, from Stockholm (b. 1750 and d. 1800), who studied medicine and taxidermy. While researching and writing about owls, he became his province’s medical officer (doctor). He added descriptions to some existing classifications under Linnaeus for certain owls. One reader thought that Tengmalm had discovered a new owl and attributed this to him by naming it “Tengmalm’s Owl.” The Owl was later named “Boreal,” but it is still known as Tengmalm’s Owl in Europe.

Areas most commonly known for using this name are Eurasia and Scandinavian countries.

Richardson’s Owl

Several plants and animals are named for Sir John Richardson of Scotland, a surgeon, Arctic consultant, and naturalist. He was highly regarded in each field and served as a consultant to the government, the military, and other naturalists such as Charles Darwin. Areas most commonly known for this name include Arctic areas and Scotland.

Boreal Owl – Aegolius funereus (Linnaeus circa 1758)

The name Boreal Owl is associated with North America. “Boreal” is related to the climate zone just south of the Arctic. This zone is a cold temperate region with taiga and coniferous forests. In 1758 Linnaeus classified this Owl.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Aves
  • Order: Strigiformes
  • Family: Strigidae
  • Genus: Aegolius
  • Species: Funereus

The Boreal Owl’s Family name, Strigidae, is what most owls fall under, meaning a “common” owl. The Genus, Aegolius, indicates a certain type of screech owl and is historically associated with bad omens, illness, and superstition. The species Funereus comes from the Latin term meaning “of a funeral” or “fatal.”

Boreal Owl perched on branch in snow

Serious in nature, the males are territorial, but their territories match their size: little. The male Boreal Owl will intensely sing until he finds his monogamous mate, much like human beings! The most common song you will hear is from the male, guarding his tiny territory and trying to attract a spouse. As a female owl approaches, the male’s call will become almost like stuttering, with rapid, short bursts of up to 300 sounds each before a pause! That is some effort!

In contrast, the female Boreal Owl is quite tight-lipped. Her vague, higher-pitched song is rarely heard.

How to Identify a Boreal Owl

The most dramatic features of the Boreal Owl are the large white facial discs edged with black. These curved spheres look almost like huge aviator goggles. The face of the Boreal Owl is itself a grayish white color, with the body being dark brown with white spots. The head is brown with tiny white dots, and the chest is white with brown streaks. Standing only 11″ tall, this Owl has a wingspan of up to 24″. The Boreal Owl has no ear tufts. The feet of the Boreal Owl are feathered, and the claws are black.

Boreal Owl’s Tail Tale

The tail of the Boreal Owl is like no other owl’s tail on earth! If you see at least three rows of white streaks or dots when their tail is folded, you know you have spotted the uncommon Boreal Owl!

feather

Habitat: Where do Boreal Owls Live?

Range of Boreal Owl (Aegolius funereus)

These owls were thought to only breed in Canada and northern Europe until recently when scientists discovered that the Boreal Owls are abundant in Alaska and live as far south as the Cascade and Rocky mountains of the United States. At the southern latitudes, they occupy only the highest elevations. Occasionally they can be found in parts of New England, but this is rare.

Preferring spruce and pine forest, it was a surprise when a 1978 report from Minnesota listed hundreds of nests in aspen forests! Since then, bird watchers have been alert for these tiny recluse owls, and observations of Boreal owls have come from Washington, Wyoming, Colorado, Montana, and Idaho.

The Boreal owls prefer densely wooded areas with coniferous (fir, pine, spruce, cedar) and deciduous (maple, oak, balsam, birch) trees. Throughout Canada and Alaska, the Boreal Owls are heard quite frequently but to see one takes stealth and determination as they are quite small and perch high up in limbs covered by other branches. Their nests are in old northern Flicker nesting cavities in mature trees.

Fun Fact: 93% of the song perches that male Boreal Owls used to attract a female were coniferous (evergreen trees) and averaged 60 feet tall. 

Circumpolar

Boreal Owls are circumpolar creatures, which means their habitat gravitates to either the North Pole or the South Pole. In this Owl’s instance, it is located near the North Pole in a circular fashion around the globe, spanning Northern Europe, Northern Asia, Alaska, and Canada. In higher elevations, similar to conditions experienced in more northern locales, they live in the northern United States.

Boreal Owls roost in some of the “tallest tree” forests in the world, in cold climates with snow and ice. Choosing towering trees positioned close together allows them to shelter from the harshest weather and take refuge from predators.

Range and Migration

Range

This tiny Owl spans large regions of several continents and vast elevations. Boreal Owl homes are in Alaska, Canada, Northern areas of the United States, Northern Europe, and Northern Asia. Preferring mountainous regions of dense forest, the Boreal Owl lives at altitudes of up to 10,000 feet! In subalpine and northern forest belts across the world, this small, innocuous Owl blends with the snow and trees of its landscape, helping to camouflage it against predators.

Migration

Boreal owls seldom migrate; when they do, they search for a consistent and plentiful food supply. Their migration can take short distances, but they are mostly sedentary birds. Boreal owls rely on wooded forests and old trees for their habitat and breeding.

Behavior

The Boreal Owl prefers to be alone outside the mating season, and their ranges are kept separate from other Boreal owls. It is not an easily studied animal living in remote and dense forested areas and being small enough to hide well. They are solitary owls that do not communicate with each other aside from their mating and brooding activities.

Hunting for Food

Hunting for Food

The Boreal Owl is a nocturnal feeder that listens closely for its prey to make a sound and then dives down to capture it in its talons. One of the Owl’s ear openings is higher than the other to differentiate sounds for determining the exact location of its next meal. The Boreal Owl’s hearing is so keen that it can detect prey under snow and dense vegetation.

Due to the usually snow-covered terrain of the Boreal Owls home, acute hearing is crucial for finding food. Small mammals cannot battle the cold ground above the snow, so they tunnel and dig through the snow to make nests and homes. The Boreal Owl sits motionless and soundless as it turns up the volume of its near bionic hearing to locate tiny scratching noises that mammals make when digging tunnels. The Owl’s hearing is so keen that it can dive down and pluck its meal from under the snow without seeing it!

These puffy watchers love to eat voles, and where there is a plentiful supply of voles, there is a large population of Boreal Owls! The Owl will change perches high up in the trees until it is satisfied with the availability of small mammals such as voles and mice. The red-backed vole is proliferous in Colorado at elevations over 9,800 feet. At the same locations, observers found the highest (no pun intended) density of Boreal Owls! Voles accounted for 80% of the owls’ diets!

In these higher elevations, it is common for the owls to find “frozen food” to eat, and their process of thawing the meals is to sit on it and “brood” as if it were an egg! When saving food, the Boreal Owl stores its cache in the hollow or crook of a tree.

Boreal Owls are known as “sit and wait” predators because their hunting strategy is to perch silently on a tree limb, listening and watching for the movement of small mammals. As they are hunting, they fly in a zig-zag pattern to different perches in the forest to find the most opportunistic location. Boreal owls do not actively pursue their prey as do other raptors, and once they spot their next meal, they swoop down, clutch it in their talons, and bite the head to kill it. Flying the dead mammal to a safe spot to store it or eat it, the Boreal Owl will eat its meals in small pieces and regurgitate one ball of hair and bones once it has finished.

These five-ounce fliers skirt the ground as they hone in on their prey that they have eyed high above on their perch. Their feathers taper down in density to allow the air to circulate quickly, providing no resistance. This, in turn, provides an absolutely silent flight for the Boreal Owl. This silence is necessary to catch their prey without alerting the small mammal to its imminent demise.

The soundless nature of the Boreal Owl’s movements also protects them from alerting larger raptors that may see the tiny Owl as an opportunistic meal.

Boreal Owl Habitat

Courtship, Mating, and Nesting

Boreal owl looking out of nest in tree hollow, Switzerland

It’s all about the female during courtship, mating, and nesting! The breeding season can be anytime between February and July! The mating ritual begins in late winter or early spring when the male searches out an area with plenty of trees and sings at night to attract a female and to defend its location. Boreal Owls love to nest in tree cavities, and it’s the male’s job to provide several options, which the female visits before choosing to make a nest.

Each potential nest hole is where the male bird calls out to the female, frequently switching his perch to other appropriate cavities to mark his territory and communicate to the female. The tree cavity often comes from an abandoned woodpecker’s nest and is usually positioned exceptionally high (up to 80 feet) off the ground. In extreme northern Europe, it is usual for the Boreal Owl to use nest boxes provided by bird watchers.

Once a female Boreal owl has chosen a nest, the male begins his nighttime territorial song, which can be loud and repetitive, causing quite a commotion with humans in the area!

A fun fact is that during this courtship process, the male finds food and feeds the female!

Another fun fact is that, unlike most owls who mate for life, the Boreal Owls are only monogamous for the season!

Breeding and Brooding

After inspecting the tree cavity nest and approving it, the female will lay eggs several days later. The eggs are laid one or two days apart, and the eggs hatch in the same order. The female will lay 2 to 10 white eggs and incubate them for an average of 30 days. During the incubation, the male forages for food and brings it back for the female to eat. Once the eggs hatch, the female Boreal Owl stays with them full-time while the male continues to hunt and gather the food! The female will feed the young hatchlings, breaking the food into small pieces.

If food is scarce, only the eggs that hatched first will survive, with the female only feeding the largest hatchlings.

Until the hatchlings are 30 days old, the female Boreal Owl will only leave the nest to bring out waste once a day.

After ten days, the young owls will open their eyes because they are born blind. They will begin to hop and venture out of the nest in four weeks. The baby birds “fledge” or fly out of the nest after 30 days; at this point, the female will also begin to hunt food. The young have five more weeks to learn the art of hunting for food, and then they will be responsible for themselves.

The male stays away from the nest during “brooding” except to bring food for the female and hatchlings.

Fun Fact: In years with plentiful food supply, the female Boreal Owl will abandon the hatchlings after they “fledge” to mate with another male and lay another brood of eggs!  

Another fun fact is that North American Boreal Owls produce only 2 to 5 eggs, but European Boreal Owls have as many as 18 eggs!

Boreal Owl Juvenile (Tengmalm's)

Day Roosting

These adorable furry, feathered friends prefer safety and security over hijinks adventures. During the day, they can be found about 20 feet above the ground in a tree on a branch close to the trunk in densely wooded areas. They are preyed upon by larger owls and raptors due to their small size.

Young Boreal Owls

The young Boreal hatchlings arrive with their eyes closed and only open them after ten days. They don’t leave the nest for 30 days; after that, it’s another 40 days before they scavenge food on their own and fly effortlessly. These immature owls are a sooty, chocolate brown with some spots and faded white streaks. Their facial discs are black and less noticeable than the stark white discs of adulthood.

Young female and male Boreal Owls reach reproductive age after 9 months.

A longevity study tracking Boreal male owls found that between 50% and 70% of young owls did not reach adulthood. A Boreal owl’s lifespan averages 8 years, with 16 years being the oldest of any tracked owl.

When Boreal hatchlings are in the nest, they make begging calls to tell their mother they are hungry!

State and Federal Laws for Boreal Owls

Though federal and state laws protect the Boreal Owl, Birdlife International categorizes Boreal owls as “least concern.” Boreal owls have shown an ability to adapt to a somewhat developed habitat as long as housing and construction leave part of their forests untouched.

The ICUN List for Threatened Species, which categorizes 41,000 species of animals, lists the world status of the Boreal Owl as “least concern” also.

US Migratory Bird Act protects the Boreal Owl, and the US Federal List has them in the “no special status” category.

These classifications can be misleading despite being labeled as a species of little conservation concern. The point is that this tiny Owl is unfamiliar because of its naturally shy nature and preference for high, remote locations. There is extensive research on the Great Horned Owl and The Barn Owl, for example. Not so with Boreal Owls. The Boreal Owl species is generally accepted to be uncommon, and the lack of information regarding this species could elevate the concern level in the coming years.

The Minnesota Department of Natural Resources lists the Boreal Owl as a “special concern.” In Idaho, this owl species has a “great conservation need.” This is due to the significant logging business and clear-cutting in Idaho.

To read more about recent research done in Minnesota on Boreal Owls, check out the Western Great Lakes Region Owl Survey.

Boreal Owl - 70birds Birdhouse Plans Index

Boreal Owls as Prey

Due to the small size of Boreal Owls, they are vulnerable to other raptors such as Pine Martens, Cooper’s Hawks, Goshawks, and larger owls like the Great Horned Owl, Ural Owl, and the Tawny Owl.

Predators of the Boreal Owl

Great Horned Owls
Ural Owls
Tawny Owls
Goshawks
Cooper’s Hawks
Martens
Red Squirrels

Can You Say Reverse Sexual Dimorphism Ten Times Fast?

The Boreal Owl boasts the most drastic reverse sexual dimorphism you will ever see in American owls. What is this, and why is it important, you may ask? The usual order is for a male animal to be larger than the female version of that animal. That is called sexual dimorphism. In reverse sexual dimorphism, the opposite is true. The female is larger than the male. For raptors (predatory birds), the female is larger than the male. This phenomenon is “reverse” sexual dimorphism.

Boreal Owls have the most extreme form of females being larger than males.

Males

Building a Boreal Owl Bird House Nest

With nesting boxes for housing Boreal Owls and their brood, much success has been found, mostly in Europe.

When building your own Boreal Owl nesting box, use pine or cedar with a textured surface so the small claws can grip the sides. For a complete how-to guide, check out the link at 70birds.

FAQs

Question: How long does it take for Boreal Owls to mate?

Answer: Once the female Boreal Owl has chosen a nest, she will stay in or near the nest for an average of a week before the male fertilizes her. After fertilization, the female will lay the first egg within a day or two and then lay an egg every other day until she is done. During that time, the male consistently hunts and brings back food for the female and himself. The entire breeding period starts in late February and can last up to five months.

Question: Will Boreal owls show themselves in open areas?

Answer: These tiny owls seek out densely forested areas with tall trees to roost. Because of their solitary nature and out of self-preservation, they will not appear in any expanse that is not wooded or covered. When perching to hunt, the limbs below the Owl’s perch may be bare, but above the perch must be blanketed with heavy brush or leaves to cover them from their predator’s views. Boreal owls are especially vulnerable to larger owls and hawks, and their eggs are susceptible to the red squirrel.

Question: Where can I find a Boreal owl?

Answer: Boreal owls are found in cold temperate climates like the zone just south of the Arctic. They are abundant in Alaska and Canada, Northern Europe, and Northern Asia and can be found at higher elevations in the Rocky Mountains. They prefer evergreen forests with mature trees and perch above 20 feet off the ground on a limb close to the tree’s trunk. They blend in with their mountainous landscape and are so small that you may overlook them.

Question: How long do Boreal owls live?

Answer: The Boreal Owl has a lifespan of seven years compared to all owls with a lifespan of 10 years. It could be because of their small size and loud call that makes it vulnerable to larger raptors who are nocturnal. It could also be the Boreal Owl’s total reliance on coniferous and deciduous forests for all aspects of survival. As forestation becomes more widespread, their potential habitat decreases.

Last Thoughts on the Boreal Owl

If you have the Boreal Owl on your list of birds to watch, you may want to invest in a down parka and strong binoculars. Maybe even an oxygen tank as well. These owls are noted for their independent, solitary nature and love of remote coniferous forests at high elevations in the cold temperate climate near the Arctic. This owl species is considered uncommon and even rare, and catching a glimpse of a tiny spotted feather puff high up in a fir tree is a truly coveted event.

They look almost absurdly small; with their boxy head and shiny, gleaming eyes, they look quite like stuffed animals. Their entire body is covered in fur, right down to their nails. If you have the patience and outerwear to wait for a shy Boreal owl to come out at night and hunt, you may be pleasantly surprised at their nonchalance when they soar to a perch above your head. Having little contact with humans has given the Boreal Owl a tolerance for nearby people; however, they are not adaptable to any other environment than their own.

The best bet would be to pitch a tent in a Canadian forest and listen for the male owl’s territorial screech during the spring mating season. Let me know how your adventures turn out!

Research Citations

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