The Great Grey Owl

The Great Grey Owl

Introduction

The Great Grey Owl is the largest species of owl by length in the world. It can be found in the Northern Hemisphere, and it is the only species in the genus Strix found in both Eastern and Western Hemispheres (Boyer and Hume, 1991, p. 112). Other names given to Great Grey Owl include the spruce owl, sooty Owl, cinereous Owl, and spectral Owl. It is a very elusive bird that is not easy to find. It is one of the tallest owls in the United States. It is also found in other parts of the world, such as Russia, Scandinavia, Siberia, and Mongolia. This paper explores the characteristics of the Great Grey Owl, including its taxonomy, description, diet, breeding, habitat, wild origins, and its life span.

Taxonomy

The Great Grey Owl belongs to the Kingdom Animalia, phylum Chordata, subphylum Vertebrata, class Sarcopterygii, order Strigiformes, family Strigidae, genus Strix, species Strix nebulosa, subspecies Strix nebulosi lapponica, and subspecies Strix nebulosa nebulosa. There are two subspecies known to exist in North America and Eurasia. The first one is the Strix nebulosa lapponica, which was identified by Thunberg in 1798. This subspecies is mainly found in Northern Eurasia, from Siberia, Lithuania, Mongolia, Kazakhstan, and northern China.  The other subspecies identified by Forster in 1772 are the Strix nebulosa nebulosa, which is found in North America from Alaska through Canada to southwestern Quebec. It is also found in northern California, western Montana, and north-eastern Minnesota (Mikkola (2014, p. 82).

Description

The Great Grey Owl is usually dressed in a gray suit with a bow tie across its neck. It has broad wings and a long tail. Adults have a large rounded head with a grey face and yellow eyes. The underparts are light with dark streaks. The upperparts are grey in color with pale bars. It has a “bow-tie” below its beak. The Owl dwarfs most other owls in size but not by weight. Much of their weight is due from the feathers. Males are smaller in size than the females.  The Great grey owl is bigger than a Great Hormed Owl in weight but not in size. It is however smaller than a Bald Eagle. According to Mikkola (2014, p. 112), the eagle is bigger than the Eurasian eagle owl and the Blakiston’s fish owl. It is therefore considered as the largest Owl in the world. The body per se is very small and its size is deceptive. The length of this eagle ranges from 61 to 84 cm with an average length of 72 cm for females and 67cm for males. The weight of an adult Great grey owl is 580-1900 grams. This translates to an average of 1290g for females and 1000 grams for males. Wings go beyond 152 cm with an average of 140 cm for males and 142 cm for females. The sound produced by an adult Great Grey Owl is a series of deep rhythmic whoos. The music is a soft, low-pitched hoot “whooooo-ooo-ooo,” with the notes emitted slowly for 6 to 8 seconds. The Owl repeats its calls every 15 to 30 seconds. The call is used as a territorial declaration, and its sound can be heard as far as 800m under the right conditions. Most of the calling starts after dust and peaks before midnight and peaks again later in the night. The Great Grey Owl snaps its beak, spreads its wings, and growls when threatened.

In most cases, the adults are generally silent. The young ones may hiss, chatter, or shriek. The Owl can be tamed, and they produce higher-pitched hoots when given food by humans (Boyer and Hume, 1991, p. 32). The Owl is a nocturnal bird (most active at night). It also operates at dusk and just before dawn. The Owl flies with soft, slow wingbeats. The Owl can fly close to the ground, usually less than 6 meters up except when flying to a nest.

Diet

The Great Grey Owl is a hunting bird. It hunts mainly in the mornings and late afternoon, especially during winter. It can also hunt during other daytime hours and nights. The primary prey for the large Great Grey Owl is the rodents (forms 80 to 90% of diet). Voles are the most crucial food in Alaska and Canada (Duncan, 2013, p. 68).  In California, pocket gophers are the primary diet for the Owl. The Owl can also feed on other mammals such as mice, rats, moles, rabbits, shrews, chipmunks, and squirrels. Birds are very rare to and form a small percentage of the diet. The birds captured include small hawks, crows, and American Robin. The other unique food of the Great Grey Owl comprises of frogs, toads, insects, and snakes. The Great Grey Owl uses the criteria of “sit and wait” for the prey to come. If the ground is covered by snow, the Owl will hunt by hearing alone, plunging into the snow targeting small rodents moving underneath as far as 30cm (Mikkola, 2014, p. 52).

Breeding

The courtship of the Great Grey Owl involves feeding and mutual preening between females and males (Volman, 1994, p. 47).  The courtship primarily starts in midwinter. The male approaches the female with food in its beak, and the food is passed with both birds closing their eyes. The male attracts the female to a nest using calls. The male selects the best nest site. The Great Grey Owl does not build its own nest; rather, it prefers abandoned nests of other birds of prey. The nests are made of ravens and crows with snags in the hollowed top. These nests are found in forests. A female Great Grey Owl lays 2 to 5 (average 3) eggs with an interval of 1 to 2 days. The average size of the eggs is 42.7mm in width and 53.5mm in length. The incubation period lasts for 28 to 29 days, starting with the first egg laid. The females do the incubation while the male provides food for the female and the young ones after hatching. The female will tear the food in tiny pieces to feed the young. The young take about 3 to 4 weeks before leaving the nest when they are capable of climbing well (Volman, 1994, p. 89).  There is usually a fledging period that takes place after eight weeks, and the young ones remain near the nest for several months, while still under the care of the female. The Great Grey Owls are single-brooded but will readily lay replacement clutches if the first clutches or brood is lost. Both males and females aggressively defend their nests. The even drive off large predators like the black bear. These owls are semi-nomadic with irregular site or mate fidelity. Food resources mainly attract them, and this makes them occupy the same location for a considerable amount of time even years before they move to new areas (Boyer and Hume, 1991, p. 112).

Habitat

The wet evergreen forests in the far North of Canada, also known as the Taiga has been identified as the home to these birds (Duncan, 2013 p. 24). The forests have provided a very favorable environment where the birds can hunt among the meadow trees and in the other open areas with scattered trees. However, in the United States, the birds have been found to reside in the fir and pine forests in California and Oregon. The birds have been discovered to take advantage of the high altitudes ranging from 2500 and 7500 feet; however, during the cold months of the winters, these owls often migrate downslope to the woodlands of Oak situated in the lower altitudes with mixed trees that commonly shed their leaves and the evergreen forests. This migration has been associated with the harsh montane temperatures on the high elevations (Stoffel, 2004, p. 46).

The habitats for these birds have not been appropriately specified, there is very scarce information, but the little available information available shows that their likelihood habitats are Montana. Surveys done on the birds indicate that they have been found to use the pine mostly, and the fir in Montana, other information regarding habitats for the grey owls, have stated clearly that the birds require dense forests. For this reason, the birds live mostly in the dense coniferous and the hardwood forests consisting of pine and spruce located near water bodies. These wet environments provide the birds with unique conditions to enable them to scavenge for food in the wet meadows and the bogs (Duncan, 2013 p. 84).

For nesting purposes, these birds have been found to move from the wet areas to expose tops of large broken off tree trunks where they locate their nests (this is common in the south) however in the North, these birds often look for other deserted birds’ nests e.g., hawk nests. Franklin (1988) states that in situations where the birds are not able to find suitable habitats, the mistletoe usually near bogs have also provided excellent nests for the birds.

Origin

The origin of these birds has not been appropriately documented, but the pieces of evidence from research works, indicate the owls could have existed from the 18th century (Campbell, 1994, p. 67). Some have even suggested that the owls could be associated with dinosaurs; however, these accounts cannot be relied on as they do not provide accurate information.  The first Great Gray Owl’s net was discovered in Canada by Andrew Graham in 1772 at Fort Severn in Ontario. Dr. Richardson also found some owl nests near the Great Bear Lake in the Northwest Territories of Canada. Johann Friedrich Gmelin gave the description differentiating the Great Gray Owl from the other owls in 1788. John Latham, in 1790, published the story of the Great Gray Owl found in the mountains of eastern Siberia, subsequently giving it the name Strix barbara; this could have been the origin of the German Great Gray Owl. (Campbell, 1994, p. 72).  Publications in Sweden have indicated that the birds could have been shot in the regions as early as 1812. In Finland, the first observation was done in 1846 in Espoo with a subsequent observation in Helsinki in the year 1886 by John Wolley. There have been no clear works to show the exact origin of these birds; however, the overall understanding of the birds should be the original descriptions and naming of the bird, and the initial record of the bird’s nest belongs to Canada (Mikkola, 2014, p. 112).

Lifespan

The Great Gray Owl reaches sexual maturity at the age of 3, at the age of 3 years, the owls can reproduce. The owls have been found to have a lifespan of 12 years while in the wild, however, the lifespan has been found to increase considerably for the owls in captivity with lifespan ranges between 30 or even 40 years. This is evidence of the effects that result from habitat destruction, subsequently limiting the bird’s lifespan. Other factors that limit the lifespan of these birds in the wild may result from starvation in the wild (Campbell, 1994, p. 80).

Behavioral issues when the Great Grey Owl (or birds in general) is kept in captivity

Just like other birds, there is an abnormal behavior of the Great Grey Owl when in captivity. The unusual responses can be categorized collectively as ingestive, or eliminative stereotypies. When under captive or commercial conditions, the Great Grey Owl shows a range of abnormal behaviors. These behaviors include feather pecking, feather plucking, cannibalism, stereotypies, sham, vent, and toe pecking. These behaviors are self-injurious or harmful to other individuals (Stoffel, 2004, p. 96).