Great Grey Owl

Great Grey Owl

Great gray owl, Phantom of the North, Cinereous owl, Spectral owl, Lapland owl, Spruce owl, Bearded owl, Sooty owl

Kingdom
Phylum
Class
Order
Family
Genus
SPECIES
Strix nebulosa
Population size
50-100 thou
Life Span
12-40 yrs
WEIGHT
580-1,900 g
LENGTH
61-84 cm
WINGSPAN
140-152 cm

The Great grey owl is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in the genus Strix found in both the Eastern and Western Hemispheres. Adult Great grey owls have a large rounded head with a grey face and yellow eyes with darker circles around them. The underparts are light with dark streaks; the upper parts are grey with pale bars. These owls do not have ear tufts and have the largest facial disc of any raptor. There is a white collar or "bow tie" just below the beak. The long tail tapers to a rounded end. The males are usually smaller than females, as with most owl species.

Distribution

Great grey owls breed in North America from as far east as Quebec to the Pacific coast and Alaska, and from Finland and Estonia across northern Asia. They are permanent residents, although northerly populations may move south and southeast when food is scarce. In Europe, they are found breeding in Norway and Sweden and more numerously through Finland and Russia. In northern areas, Great grey owls prefer to breed in the dense coniferous forests of the taiga, near open areas, such as meadows or bogs. In Oregon and California, they may nest in mixed oak woodlands. Once believed to require a cold climate, these owls are known now to survive in a few areas where summer temperatures exceed 100 °F (38 °C).

Great Grey Owl habitat map

Climate zones

Habits and Lifestyle

Great grey owls are generally solitary birds and outside of the breeding season prefer to spend their time singly. They are very powerful hunters that wait, listen, and watch for prey, then swoop down; they also may fly low through open areas in search of prey. They frequently hunt from a low listening post which can be a stump, low tree limb, fence post, or road sign. Their large facial disks, also known as "ruffs", focus sound, and the asymmetrical placement of their ears assists them in locating prey, because of the lack of light during the late and early hours in which they hunt. On the nesting grounds, Great grey owls mainly hunt at night and near dawn and dusk; at other times, they are active mostly during the night. Great grey owls are not as aggressive as most other alpha predators. They are less likely to attack each other or potential threats than are other large predatory birds. They do not protect a large nesting territory, nor do they defend hunting territories through aggression. As an exception, the female is aggressive in protecting eggs and owlets. She is especially alert and aggressive when fledglings first leave the nest but cannot yet fly, and thus are extremely vulnerable. Great grey owls communicate with a series of very deep, rhythmic 'whoos', which is usually given in correlation to their territories or in interactions with their owlets. At other times, adults are normally silent. The young may chatter, shriek, or hiss.

Group name
Seasonal behavior

Diet and Nutrition

Great grey owls are carnivores and rely almost fully upon small rodents. What species they eat depends on which small mammals are most abundant and available. These include lemmings, pocket gophers, voles, hares, moles, shrews, weasels, thrushes, grouse, Canada jays, mountain quail, small hawks, and ducks.

Mating Habits

MATING BEHAVIOR
REPRODUCTION SEASON
March-May
INCUBATION PERIOD
28-36 days
BABY NAME
owlet, fledgling
BABY CARRYING
4 eggs

Great grey owls are monogamous and form pairs. Nesting usually occurs from March to May. They do not build nests, so they typically use nests previously used by a large bird, such as a raptor. They will also nest in broken-topped trees and cavities in large trees. The female typically lays 4 eggs and incubates them from 28 to 36 days. Owlets hatch blind and helpless. Brooding lasts 2 to 3 weeks, after which the female starts roosting on a tree near nests. The young jump or fall from the nest at 3 to 4 weeks, and start to fly 1 to 2 weeks after this. Immediately after fledging, the white, fuzzy owlets must use beak and feet to climb back into trees. The female is on guard at this time and may be aggressive toward potential predators. Most owlets remain near their natal sites for many months after fledging. Normally the male hunts for his mate and the young throughout the nesting period. Once the owlets begin the fly, the female typically withdraws and the male continues to feed the young until they can hunt on their own in the autumn. The young owls go off on their own by winter.

Population

Population threats

The harvest of timber from the Great grey owl's habitat is, perhaps, the greatest threat to this species. Intensified timber management typically reduces live and dead large-diameter trees used for nesting, leaning trees used by juveniles for roosting before they can fly, and dense canopy closures in stands used by juveniles for cover and protection. If perches are not left in clearcuts, Great grey owls cannot readily hunt in them. Although human-made structures (made specifically for use by this species) have been utilized by these owls, the species is far more common in areas protected from logging. Livestock grazing in meadows also adversely affects Great grey owls, by reducing habitat for preferred prey species. Other dangers to these birds include rodenticides, and collisions with vehicles.

Population number

According to the IUCN Red List, the total population size of the Great grey owl is 50,000-99,999 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are increasing.

Fun Facts for Kids

  • Great grey owls have excellent hearing and may locate (and then capture) prey moving beneath 60 cm (2.0 ft) of snow in a series of tunnels solely with that sense. They then can crash to a snow depth roughly equal to their own body size to grab their prey. Only this species and, more infrequently, other fairly large owls from the genus Strix are known to "snow-plunge" for prey, a habit that is thought to require superb hearing not possessed by all types of owls.
  • Due to the lack of territorial aggressiveness Great grey owls are difficult to find in the field. Most owls respond to their own species calls if played back in a nesting territory. Great grey owls will often ignore such calls. They also do not flush every time human approaches or drives past. Great grey owls often remain still even if a human is nearby and therefore they are often overlooked or unnoticed.
  • Due to their large size, Great grey owls have few natural predators. They are even able to fend off animals as large as Black bears when defending their nests!

References

1. Great Grey Owl on Wikipedia - https://en.wikipedia.org/wiki/Great_grey_owl
2. Great Grey Owl on The IUCN Red List site - https://www.iucnredlist.org/species/22689118/93218931

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