The snowy owl (''Bubo scandiacus''), also known as the polar owl, the white owl and the Arctic owl,
is a large, white
owl of the
true owl family.
Snowy owls are native to the
Arctic
The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
regions of both North America and the
Palearctic
The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa.
The realm consists of several bioregions: the Euro-Sib ...
, breeding mostly on the
tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
.
It has a number of unique adaptations to its habitat and lifestyle, which are quite distinct from other extant owls.
One of the largest species of owl, it is the only owl with mainly white plumage.
[ Males tend to be a purer white overall while females tend to more have more extensive flecks of dark brown.][Holt, D. W., M. D. Larson, N. Smith, D. L. Evans, and D. F. Parmelee (2020)]
Snowy Owl (''Bubo scandiacus'')
version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. Juvenile male snowy owls have dark markings that may appear similar to females until maturity, at which point they typically turn whiter. The composition of brown markings about the wing, although not foolproof, is the most reliable technique to age and sex individual snowy owls.
Most owls sleep during the day and hunt at night, but the snowy owl is often active during the day, especially in the summertime.[ The snowy owl is both a specialized and generalist hunter. Its breeding efforts and global population are closely tied to the availability of tundra-dwelling lemmings, but in the non-breeding season, and occasionally during breeding, the snowy owl can adapt to almost any available prey – most often other small ]mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
s and northerly water birds, as well as, opportunistically, carrion
Carrion () is the decaying flesh of dead animals, including human flesh.
Overview
Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
.[ Snowy owls typically nest on a small rise on the ground of the tundra.][Hume, R. (1991). ''Owls of the world''. Running Press, Philadelphia.] The snowy owl lays a very large clutch of eggs, often from about 5 to 11, with the laying and hatching of eggs considerably staggered.[ Despite the short ]Arctic summer
The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains visible at the local midnight. When the midnight sun is seen in the Arctic, th ...
, the development of the young takes a relatively long time and independence is sought in autumn.[
The snowy owl is a nomadic bird, rarely breeding at the same locations or with the same mates on an annual basis and often not breeding at all if prey is unavailable.][ A largely ]migratory bird
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting b ...
, snowy owls can wander almost anywhere close to the Arctic, sometimes unpredictably irrupting to the south in large numbers. Given the difficulty of surveying such an unpredictable bird, there was little in-depth knowledge historically about the snowy owl's status. However, recent data suggests the species is declining precipitously.[Bent, A. C. (1938). ''Life Histories of North American Birds of Prey (part 2), Orders Falconiformes and Stringiformes (Vol. 170)''. US Government Printing Office.] Whereas the global population was once estimated at over 200,000 individuals, recent data suggests that there are probably fewer than 100,000 individuals globally and that the number of successful breeding pairs is 28,000 or even considerably less. While the causes are not well understood, numerous, complex environmental factors often correlated with global warming
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
are probably at the forefront of the fragility of the snowy owl's existence.[
]
Taxonomy
The snowy owl was one of the many bird species originally described by Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, ...
in his landmark 1758 10th edition of ''Systema Naturae'', where it was given the binomial name ''Strix scandiaca''. The genus name ''Bubo'' is Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
for "an horned owl" and ''scandiacus'' is New Latin
New Latin (also called Neo-Latin or Modern Latin) is the revival of Literary Latin used in original, scholarly, and scientific works since about 1500. Modern scholarly and technical nomenclature, such as in zoological and botanical taxonomy ...
for "of Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and S ...
". The former generic name ''Nyctea'' is derived from Greek meaning "night".[ Linnaeus originally described the different plumages of this owl as separate species, with the male specimens of snowy owls being considered ''Strix scandiaca'' and the likely females considered as ''Strix nyctea''.][ Until recently, the snowy owl was regarded as the sole member of a distinct ]genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
, as ''Nyctea scandiaca'', but mtDNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...
cytochrome ''b'' sequence
In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is called ...
data shows that it is very closely related to the horned owls in the genus ''Bubo'' and the species is now thusly often considered inclusive with that genus.[Wink, M. & Heidrich, P. (2000). "Molecular systematics of owls (Strigiformes) based on DNA-sequences of the mitochondrial cytochrome b gene", pp. 819–828 in: Chancellor, R.D. & Meyburg, B.U. eds. (2000). ''Raptors at Risk. Proceedings of the V World Conference on Birds of Prey and Owls''. Midrand, Johannesburg, 4–11 August 1998. WWGBP & Hancock House, Berlin & Blaine, Washington.] However, some authorities debate this classification, still preferring ''Nyctea''. Often authorities are motivated to retain the separate genus on the grounds of osteological distinctions.[Ford, N. L. (1967). ''A systematic study of the owls based on comparative osteology''. PhD diss, Univ. of Michigan, Ann Arbor.]
Genetic testing revealed a reasonably distinct genetic makeup for snowy owls, being about 8% genetically distinct from other ''Bubo'' owls, perhaps giving credence to those who count the species as separate under ''Nyctea''.[ However, a fairly recent shared origin in evolutionary history has been illustrated through a combination of genetic study and fossil review and there is little, other than osteology of the ]tarsometatarsus
The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) and me ...
, to outright distinguish the snowy owl from other modern species like the Eurasian eagle-owl
The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, and femal ...
(''Bubo bubo'').[ Genetic testing has indicated that the snowy owl may have diverged from related species at around 4 million years ago.][ Furthermore, it has determined that the living species genetically most closely related to the snowy owl is the great horned owl (''Bubo virginianus'').] On a broader scale, owls in general have, through genetic materials, been determined to be a highly distinct group, with outwardly similar groups such as Caprimulgiformes revealed to not be at all closely related. Within the owl order, typical owls are highly divergent from barn-owls.[ Furthermore, the ''Bubo'' genus likely clustered at some point during the evolutionary process with other largish owls, such as '' Strix'', '']Pulsatrix
''Pulsatrix'' is a genus of owl in the family Strigidae. They are called spectacled owls because of their prominent facial pattern. The genus contains the following species:
* Spectacled owl, '' Pulsatrix perspicillata''
* Tawny-browed owl, ...
'' and ''Ciccaba
''Strix'' is a genus of owls in the typical owl family (Strigidae), one of the two generally accepted living families of owls, with the other being the barn-owl (Tytonidae). Common names are earless owls or wood owls, though they are not the o ...
'', based on broad similarities in their voice, reproductive behaviors (i.e. hooting postures) and a similar number and structure of chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s and autosome
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes ...
s.[ A number, but not all, of extant typical owls seem to have evolved from an ancient shared common ancestor with the ''Bubo'' owls.] In addition to the question of relationship of the traditional ''Bubo'' owls to the snowy owls, ongoing ambiguity of the relationship of other similarly large-sized owls has been persistent. These have sometimes either been included in the genus or within separate genera, i.e. the '' Ketupu'' or fish owls and the ''Scotopelia
Fishing owls are a group of sub-Saharan African birds in the family Strigidae, the true owls. Fishing owls have traditionally been placed in the genus ''Scotopelia'', but DNA evidence suggests they should be included in genus ''Bubo
A bubo (G ...
'' or fishing owls. Despite the adaptive distinctions, the grouping of these large owls (i.e. ''Bubo'', snowy, fish and perhaps fishing owls) appears to be borne out via research of karyotype
A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
s.[''Owls of the World: A Photographic Guide'' by Mikkola, H. Firefly Books (2012), ]
The fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
history of snowy owls is fairly well documented despite some early confusion on how to distinguish the skeletal structure of the snowy owls from eagle-owls. It was determined that the snowy owl once was distributed much more widely and far farther to the south during the Quaternary glaciation
The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma (million years ago) and is ongoing. Although geologists describ ...
when much of the Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
was in the midst of an ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...
.[ Fossil records shows that snowy owls once could be found in Austria, Azerbaijan, ]Czechoslovakia
, rue, Чеськословеньско, , yi, טשעכאסלאוואקיי,
, common_name = Czechoslovakia
, life_span = 1918–19391945–1992
, p1 = Austria-Hungary
, image_p1 ...
, England, France, Germany, Hungary, Italy, Poland, Sardinia and Spain as well as in the Americas in Cape Prince of Wales
Cape Prince of Wales (Russian: Мыс Принца Уэльского) () is the westernmost mainland point of the Americas. It was named in 1778 by Captain James Cook of the British Royal Navy, presumably for the Prince of Wales at the time, Geo ...
, Little Kiska Island
Little Kiska Island is an island off east coast of the island of Kiska in the Rat Islands (part of the Aleutian Islands)in Alaska. It lies immediately east of Kiska Harbor it is approximately 6 kilometers long and 2 kilometers wide. The island ha ...
, St. Lawrence Island, and in Illinois
Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rock ...
.[ In the ]Late Pleistocene
The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch withi ...
the range expanded southward even more so to Bulgaria (80,000–16,000 years, Kozarnika Cave, W Bulgaria). and much of the Italian Peninsula. Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
era fossils from France, i.e. ''B. s. gallica'', showed that the snowy owls of the time were somewhat bulkier (though still notably smaller than contemporary eagle-owls of the times, which were larger than the eagle-owls of today) and osteologically more sexually dimorphic in size than the modern form (9.9% dimorphism in favor of females in the fossils against 4.8% in the same features today). There are no subspecific or other geographical variations reported in the modern snowy owls, with individuals of vastly different origins breeding together readily due to their nomadic habits.[ Despite apparent variations in body size, environmental conditions are the likely variant rather than genetics.][ No evidence could be found of phylogeographic variation in snowy owls upon testing. Furthermore, the snowy owl appears to have a similar level of ]genetic diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...
as other European owls.[
]
Hybrids
Snowy owls are not known to interbreed with other owl species in the wild, and accordingly, no hybrids of snowy owls and other owl species have yet been sighted in the wild. However, a hobby falconer in Kollnburg
Kollnburg is a municipality in the district of Regen, in Bavaria, Germany. A part of the municipal area, including the parish village of the same name, is a state-approved resort.
Geography
The community is located in the Donau Forest region in ...
, Germany, bred hybrids from a male snowy owl and a female Eurasian eagle-owl (''Bubo bubo'') in 2013.["Schnuhu": Überraschende Kreuzung – Ich bin Bayerns süßester Fratz!](_blank)
tz.de Retrieved on 7 October 2016 The two resulting male hybrid owls possessed the prominent ear-tufts (generally absent in snowy owls), general size, orange eyes, and the same pattern of black markings on their plumage from their Eurasian eagle-owl mother, while retaining the generally black-and-white plumage colours from their snowy owl father. The hybrids were dubbed "''Schnuhus''" from the German words for snowy owl and Eurasian eagle-owl (''Schnee-Eule'' and ''Uhu'', respectively). As of 2014, the hybrids had grown to maturity and were healthy.
Description
The snowy owl is mostly white. They are purer white than predatory mammals like polar bear
The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear spec ...
s (''Ursus maritimus'') and Arctic fox
The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in ...
(''Vulpes lagopus'').[ Often when seen in the field, these owls can resemble a pale rock or a lump of snow on the ground.][ It usually appears to lack ear tufts but very short (and probably vestigial) ]tufts
Tufts University is a private research university on the border of Medford and Somerville, Massachusetts. It was founded in 1852 as Tufts College by Christian universalists who sought to provide a nonsectarian institution of higher learnin ...
can be erected in some situations, perhaps most frequently by the female when she is sitting on the nest.[ The ear tufts measure about and consist of about 10 small feathers.][ The snowy owl has bright yellow eyes.][ The head is relatively small and, even for the relatively simply adapted hearing mechanism of a ''Bubo'' owl, the facial disc is shallow and the ear is uncomplicated.][ 1 male had ear slits of merely on left and on the right.][ Females are almost invariably more duskily patterned than like-age males.][ In mature males, the upper parts are plain white with usually a few dark spots on the miniature ear-tufts, about the head and the tips of some primaries and secondaries whilst the underside is often pure white.][ Despite their reputation for being purely white, only 3 out of 129 Russian museum specimens of adult males showed an almost complete absence of darker spots. The adult female is usually considerably more spotted and often slightly barred with dark brown on the crown and the underparts. Her flight and tail feathers are faintly barred brown while the underparts are white in base color with brown spotting and barring on the flanks and upper breast.][ In confusingly plumaged snowy owls, the sex can be determined by the shape of wing markings, which manifest as bars more so in females and spots in males.] However, the very darkest males and the lightest females are nearly indistinguishable by plumage.[ On rare occasion, a female can appear almost pure white, as has been recorded in both the field and in captivity.][McMorris, A. (2011). ''Snowy Owls: Age, Sex and Plumage''. Presentation Delaware Valley Ornithological Club.] There is some evidence that some of the species grow paler with age after maturity.[Dementiev, G. P., Gladkov, N. A., Ptushenko, E. S., Spangenberg, E. P., & Sudilovskaya, A. M. (1966). ''Birds of the Soviet Union, vol. 1''. Israel Program for Scientific Translations, Jerusalem.] One study's conclusions were that males were usually but not always lighter and that correctly aging is extremely difficult, sometimes individuals either get lighter, darker or do not change their appearance with age.[ On the other hand, with close study, it is possible to visually identify even individual snowy owls using the pattern of markings on the wing, which can be somewhat unique in each individual. After a fresh moult, some adult females that previously appeared relatively pale newly evidenced dark, heavy markings. On the contrary, some banded individuals over at least four years were observed to have been almost entirely unchanged in the extent of their markings.][ In another very pale owl, the ]barn owl
The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himala ...
(''Tyto alba''), the sexual dimorphism of spotting appears to be driven by genetics while, in snowy owls, environment may be the dictating factor instead.[
The chicks are initially grayish white but quickly transition to dark gray-brown in the mesoptile plumage. This type of plumage ]camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
s effectively against the variously colored lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.[moult
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...]
fewer or more broken bars are usually evidenced on the wing. The extent of white and composition of wing patterns become more dimorphic by sex with each juvenile moult, culminating in the 4th or 5th pre-basic moult, wherein the owls are hard to distinguish from mature adults.[ Moults usually occur from July and September, non-breeding birds moulting later and more extensively, and are never extensive enough to render the owls flightless.][ Evidence indicates that snowy owls may attain adult plumage at 3 to 4 years of age, but fragmentary information suggests that some males are not fully mature and/or as fully white in plumage that they can attain until the 9th or 10th year.] Generally speaking, moults of snowy owls occur more quickly than do those of Eurasian eagle-owls.[
The toes of the snowy owl are extremely thickly feathered white, while the claws are black.][ The toe feathers are the longest known of any owl, averaging at , against the great horned owl which has the 2nd longest toe feathers at a mean of ][ Occasionally, snowy owls may show a faint blackish edge to the eyes and have a dark gray cere, though this is often not visible from the feather coverage, and a black bill.][ Unlike many other whitish birds, the snowy owl does not possess black wingtips, which is theorized to minimize wear-and-tear on the wing feathers in the other whitish bird types. The conspicuously notched primaries of the snowy owl appear to give an advantage over similar owls in long-distance flight and more extensive flapping flight. The snowy owl does have some of the noise-canceling serrations and comb-like wing feathers that render the flight of most owls functionally silent, but they have fewer than most related ''Bubo'' owls. Therefore, in combination with its less soft feathers, the flight of a snowy owl can be somewhat audible at close range.][ The flight of snowy owls tends to be steady and direct and is reminiscent to some of the flight of a large, slow-flying falcon.][ Though capable of occasional ]gliding flight
Gliding flight is heavier-than-air flight without the use of thrust; the term volplaning also refers to this mode of flight in animals. It is employed by gliding animals and by aircraft such as gliders. This mode of flight involves flying a s ...
, there is no evidence that snowy owls will soar. It is said that the species seldom exceeds a flying height of around even during passage.[ While the feet are sometimes described as "enormous", the tarsus is in osteological terms relatively short at 68% the length of those of a Eurasian eagle-owl but the claws are nearly as large, at 89% of the size of those of the eagle-owl.][ Despite its relatively short length, the tarsus is of similar circumference as in other ''Bubo'' owls. Also compared to an eagle-owl, the snowy owl has a relatively short decurved rostrum, a proportionately greater length to the interorbital roof and a much longer sclerotic ring surrounding the eyes while the anterior opening are the greatest known in any owl.][ Owls have extremely large eyes which are nearly the same size in large species such as the snowy owl as those of humans. The snowy owl's eye, at about in diameter, is slightly smaller than those of great horned and Eurasian eagle-owls but is slightly larger than those of some other large owls.][ Snowy owls must be able to see from great distances and in highly variable conditions but probably possess less acute night vision than many other owls.][ Based on the study of ]dioptre
A dioptre (British spelling) or diopter (American spelling) is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dioptre = 1 m−1. It is normally used to express the optical power of a lens or ...
s in different owl species, the snowy owl was determined to have eyesight better suited to long-range perception than to close discrimination, while some related species such as great horned owls could probably more successful perceive closer objects. Despite their visual limits, snowy owls may have up to 1.5 times more visual acuity than humans.[ Like other owls, snowy owls can probably perceive all colors but cannot perceive ]ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
visual pigments. Owls have the largest brains of any bird (increasing in sync with the size of the owl species), with the size of the brain and eye related less to intelligence
Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. More generally, it can ...
than perhaps to increased nocturnality and predatory behavior.
Size
The snowy owl is a very large owl.[ They are the largest avian predator of the ]High Arctic
High may refer to:
Science and technology
* Height
* High (atmospheric), a high-pressure area
* High (computability), a quality of a Turing degree, in computability theory
* High (tectonics), in geology an area where relative tectonic uplift t ...
and one of the largest owls in the world.[ Snowy owls are about the sixth or seventh heaviest living owl on average, around the fifth longest and perhaps the third longest winged.][Weidensaul, S. (2015). ''Owls of North America and the Caribbean''. Houghton Mifflin Harcourt.] This species is the heaviest and longest winged owl (as well as the second longest) in North America, the second heaviest and longest winged owl in Europe (and third longest) but is outsized in bulk by about 3 to 4 other species in Asia.[ Despite being sometimes described as of similar size, the snowy owl is somewhat larger in all aspects of average size than the great horned owl while the similarly specialized ]taiga
Taiga (; rus, тайга́, p=tɐjˈɡa; relates to Mongolic and Turkic languages), generally referred to in North America as a boreal forest or snow forest, is a biome characterized by coniferous forests consisting mostly of pines, sp ...
-dwelling great grey owl
The great grey owl (''Strix nebulosa'') (also great gray owl in American English) 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 th ...
(''Strix nebulosa''), is longer in total length and of similar dimensions in standard measurements, but is shorter winged and much less heavy than the snowy owl.[ In Eurasia, the ]Eurasian eagle-owl
The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, and femal ...
is larger in all standards of measurements than the snowy owl not to mention two additional species each from Africa and Asia that are slightly to considerably heavier on average than the snowy owl.[ Like most birds of prey, the snowy owl shows reverse sexual dimorphism relative to most non-raptorial birds in that females are larger than males.][ Sexual dimorphism that favors the female may have some correlation with being able to more effectively withstand food shortages such as during brooding as well as the rigors associated with incubating and brooding. Females are sometimes described as “giant” whereas males appear relatively “neat and compact”.][ However, the sexual dimorphism is relatively less pronounced compared to some other ''Bubo'' species.]
Male snowy owls have been known to measure from in total length, with an average from four large samples of and a maximum length, perhaps in need of verification, of reportedly .[Eckert, A. W. (1987). ''The Owls of North America, North of Mexico: All the Species and Subspecies Illustrated in Color and Fully Described''. Gramercy.][Parmelee, D. F. (1972). ''Canada's incredible arctic owls''. Beaver no. summer:30–41.][Priklonskiy, S.G. (1993). ''Snowy Owl — Nyctea scandiaca (Linnaeus, 1758)''. In: ''Birds of Russia and adjoining regions: Pterocliformes, Columbiformes, Cuculiformes, Strigiformes''. Moscow, p. 258–270. (in Russian).] In wingspan, males may range from , with a mean of .[ In females, total length has been known to range from , with a mean of and an unverified maximum length of perhaps (if so they would have the second longest maximum length of any living owl, after only the great grey owl).][ Female wingspans have reportedly measured from , with a mean of .][ Despite one study claiming that snowy owl had the highest wing loading (i.e. grams per square cm of wing area) of any of 15 well-known owl species, more extensive sampling demonstratively illustrated that the wing loading of snowy owls is notably lower than Eurasian eagle- and great horned owls.][ The conspicuously long-winged profile of a flying snowy owl compared to these related species may cause some to compare their flight profile to a bulkier version of an enormous '']Buteo
''Buteo'' is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but " hawk" is used in the New World (Etymology: ''Buteo'' is the Latin na ...
'' or a large falcon
Falcons () are birds of prey in the genus ''Falco'', which includes about 40 species. Falcons are widely distributed on all continents of the world except Antarctica, though closely related raptors did occur there in the Eocene.
Adult falcons ...
.[ Body mass in males can average from , with a median of and a full weight range of from six sources.] Body mass in females can average from , with a median of and a full weight range of .[ Larger than the aforementioned body mass studies, a massive pooled dataset at six wintering sites in North America showed that 995 males averaged at while 1,189 females were found to average .] Reported weights of down to for males and of for females are probably in reference to owls in a state of starvation
Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism's life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, de ...
. Such emaciated individuals are known to highly impaired and starvation deaths are probably not infrequent in winters with poor food accesses.[
Standard measurements have been even more widely reported than length and wingspan.][ The wing chord of males can vary from , averaging from with a median of .] The wing chord of females can vary from , averaging from with a median of .[ The ]tail
The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammal ...
length of males can vary on average from , with a full range of and a median of .[ The tail length of females can average from , with a full range of and a median of .][ Data indicates that slightly longer wing chord and tail lengths were reported on average in Russian data than in American research, however the weights were not significantly different in the two regions.][ Less widely taken measurements include the culmen, which can measure from with a median average of in males and in females, and the total bill length which is from , with an average in both sexes of .][ Tarsal length in males averages about , with a range of , and averages about , with a range of , in females.][
]
Identification
The snowy owl is certainly one of the most unmistakable owls (or perhaps even animals) in the world.[ No other species attains the signature white stippled sparsely with black-brown color of these birds, a coloring which renders their bright yellow eyes all the more detectable, nor possesses their obvious extremely long feathering.][ The only other owl to breed in the ]High Arctic
High may refer to:
Science and technology
* Height
* High (atmospheric), a high-pressure area
* High (computability), a quality of a Turing degree, in computability theory
* High (tectonics), in geology an area where relative tectonic uplift t ...
is the short-eared owl
The short-eared owl (''Asio flammeus'') is a widespread grassland species in the family Strigidae. Owls belonging to genus ''Asio'' are known as the eared owls, as they have tufts of feathers resembling mammalian ears. These "ear" tufts may or ...
(''Asio flammeus''). Both species inhabit open country, overlap in range and are often seen by day, but the short-eared is much smaller and more tan or straw-colored in coloration, with streaked brown on chest. Even the palest short-eared owls conspicuously differ and are darker than the snowy owl; additionally the short-eared most often hunts in extended flights.[Pyle, P. (1997). ''Identification Guide to North American Birds, Part I: Columbidae to Ploceidae''. Slate Creek Press, Bolinas, CA, USA.] More similar owls such as the Eurasian eagle-owl
The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, and femal ...
and the great horned owl attain a fairly pale, sometimes white-washed look in their northernmost races. These species do not normally breed nearly as far north as snowy owls but overlaps certainly do occur when snowy owls when the latter owl sometimes comes south in winter. However, even the most pale great horned and Eurasian eagle-owls are still considerably more heavily marked with darker base colors than snowy owls (the whitest eagle-owls are paler than the whitest great horned owls), possess much larger and more conspicuous ear tufts and lack the bicolored appearance of the darkest snowy owls. While the great horned owl has yellow eyes like the snowy owl, the Eurasian eagle-owl tends to have bright orange eyes. The open terrain habitats normally used by wintering snowy owls are also distinct from the typical edge
Edge or EDGE may refer to:
Technology Computing
* Edge computing, a network load-balancing system
* Edge device, an entry point to a computer network
* Adobe Edge, a graphical development application
* Microsoft Edge, a web browser developed ...
and rocky habitats usually favored by the great horned and Eurasian eagle-owls, respectively.
Vocalizations
The snowy owl differ in their calls from other ''Bubo'' owls, with a much more barking quality to their version of a hooting song.[ Perhaps as many as 15 different calls by mature snowy owls have been documented.][Sutton, G. M. (1932). ''The exploration of Southampton Island. Part II, Zoölogy. Section 2.-The birds of Southampton Island''. Memoirs of the Carnegie Museum 12 (2):1–275.] The main vocalization is a monotonous sequence that normally contains 2–6 (but occasionally more), rough notes similar to the rhythm of a barking dog: ''krooh krooh krooh krooh''...[ The call may end with an emphatic ''aaoow'', which is somewhat reminiscent of the deep alarm call of a ]great black-backed gull
The great black-backed gull (''Larus marinus'') is the largest member of the gull family. Described by the Cornell Lab of Ornithology as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. It breeds on t ...
(''Larus marinus'').[ They will call mainly from a perch but also sometimes do so in flight.][ The ''krooh'' call of the male snowy owl may perform multiple functions such as competitive exclusion of other males and advertising to females.][Taylor, P.S. (1973). ''Breeding behaviour of the Snowy Owl''. Living Bird. 12: 137–154.] The calls of this species may carry exceptionally far in the thin air of Arctic, certainly over more than , and maybe even to as much away.[ The female has a similar call to male but can be higher-pitched and/or more guttural as well as single notes which are often disyllabic, ''khuso''.][ Female snowy owls have also been known to utter chirps and high screaming notes, similar to those of the nestlings.][ Both sexes may at times give a series of clucking, squeals, grunts, hisses and cackles, perhaps such as in circumstances when they are excited.] The alarm call is a loud, grating, hoarse ''keeea''.[ Another raspier bark is recorded, sometimes called a "watchman's rattle" call, and may be transcribed as ''rick, rick, rick'', ''ha, how, quack, quock'' or ''kre, kre, kre, kre, kre''.][ A female attacking to protect her nest was recorded to let out a crowed ''ca-ca-oh'' call, whilst other owls attacking to protect the nest did a loud version of the typical call while circling before dropping down.] They may also clap their beak in response to threats or annoyances. While called clapping, it is believed this sound may actually be a clicking of the tongue, not the beak. Though largely only vocal in the breeding season, leading to some erroneous older accounts describing the snowy owl as completely silent, some vocalizations have been recorded in winter in the northern United States.[ Initially, the young of the snowy owl have a high pitched and soft begging call which develops into a strong, wheezy scream at around 2 weeks. At the point when the young owls leave the nest around 3 weeks, the shrill squeals they emit may allow the mothers to locate them.][
]
Distribution and habitat
Breeding range
The snowy owl is typically found in the northern circumpolar region, where it makes its summer home north of latitude 60° north though sometimes down to 55 degrees north.[ However, it is a particularly ]nomad
A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the po ...
ic bird, and because population fluctuations in its prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
species can force it to relocate, it has been known to breed at more southerly latitudes. Although the total breeding range includes a little over , only about have a high probability of breeding, i.e. breeding at no more than 3–9-year intervals.[ Snowy owls nest in the Arctic ]tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
of the northernmost stretches of Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...
, Northern Canada, and the Euro-Siberian region.[
Between 1967 and 1975, snowy owls bred on the remote island of Fetlar in the ]Shetland
Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom.
The islands lie about to the n ...
Isles north of mainland Scotland
Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to ...
, discovered by the Shetland RSPB
The Royal Society for the Protection of Birds (RSPB) is a charitable organisation registered in England and Wales and in Scotland. It was founded in 1889. It works to promote conservation and protection of birds and the wider environment th ...
warden, Bobby Tulloch
Robert "Bobby" John Tulloch MBE (4 January 1929 – 21 May 1996) was a naturalist from the Shetland Islands, in the north of Scotland.
Bobby Tulloch was born on a croft at Aywick on the eastern side of Yell, as the oldest of four children, ...
. Females summered as recently as 1993, but their status in the British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isl ...
is now that of a rare winter visitor to Shetland, the Outer Hebrides
The Outer Hebrides () or Western Isles ( gd, Na h-Eileanan Siar or or ("islands of the strangers"); sco, Waster Isles), sometimes known as the Long Isle/Long Island ( gd, An t-Eilean Fada, links=no), is an island chain off the west coas ...
and the Cairngorms. Older records show that the snowy owls may have once semi-regularly bred elsewhere in the Shetland
Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom.
The islands lie about to the n ...
s. They range in northern Greenland (mostly Peary Land) and, rarely in "isolated parts of the highlands", Iceland.[ Thence, they are found breeding at times across northern ]Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...
such as in Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Nor ...
and western and northern Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and S ...
. In Norway, they normally breed in Troms og Finnmark
Troms og Finnmark (; sme, Romsa ja Finnmárku ; fkv, Tromssa ja Finmarkku; fi, Tromssa ja Finnmark, lit. Troms and Finnmark in English), is a county in northern Norway that was established on 1 January 2020 as the result of a regional reform. ...
and seldom down as far south as Hardangervidda and in Sweden perhaps down to the Scandinavian Mountains
The Scandinavian Mountains or the Scandes is a mountain range that runs through the Scandinavian Peninsula. The western sides of the mountains drop precipitously into the North Sea and Norwegian Sea, forming the fjords of Norway, whereas to th ...
while breeding is very inconsistent in Finland.[
They also range in much of northern Russia, including northern ]Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part ...
, Anadyr Anadyr may refer to:
*Anadyr (town), a town and the administrative center of Chukotka Autonomous Okrug, Russia
*Anadyr District
*Anadyr Estuary
*Anadyr (river), a river in Chukotka Autonomous Okrug, Russia
*Anadyr Highlands
*Anadyr Lowlands
*Operati ...
, Koryakland, Taymyr Peninsula
The Taymyr Peninsula (russian: Таймырский полуостров, Taymyrsky poluostrov) is a peninsula in the Far North of Russia, in the Siberian Federal District, that forms the northernmost part of the mainland of Eurasia. Administrat ...
, Yugorsky Peninsula, Sakha
Sakha, officially the Republic of Sakha (Yakutia),, is the largest republic of Russia, located in the Russian Far East, along the Arctic Ocean, with a population of roughly 1 million. Sakha comprises half of the area of its governing Far ...
(especially the Chukochya River) and Sakhalin
Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh ...
.[ Breeding has also been reported sporadically to the south in the ]Komi Republic
The Komi Republic (russian: Республика Коми; kv, Коми Республика), sometimes simply referred to as Komi, is a republic of Russia located in Eastern Europe. Its capital is the city of Syktyvkar. The population of th ...
and even the Kama River in southern Perm Krai
Perm Krai (russian: Пе́рмский край, r=Permsky kray, p=ˈpʲɛrmskʲɪj ˈkraj, ''Permsky krai'', , ''Perem lador'') is a federal subject of Russia (a krai) that came into existence on December 1, 2005 as a result of the 2004 re ...
.[ Although considered part of their regular range, the last breeding by snowy owls in the ]Kola Peninsula
The Kola Peninsula (russian: Кольский полуостров, Kolsky poluostrov; sjd, Куэлнэгк нёа̄ррк) is a peninsula in the extreme northwest of Russia, and one of the largest peninsulas of Europe. Constituting the bulk ...
was in the early 1980s; similarly, breeding maps show the species in Arkhangelsk Oblast
Arkhangelsk Oblast (russian: Арха́нгельская о́бласть, ''Arkhangelskaya oblast'') is a federal subject of Russia (an oblast). It includes the Arctic archipelagos of Franz Josef Land and Novaya Zemlya, as well as the Solo ...
and the Pay-Khoy Ridge
The Pay-Khoy Range ( rus, хребет Пай-Хой) is a mountain range at the northern end of the Ural Mountains. It lies within the Nenets Autonomous Okrug.
Geography
The ridge is extended from northwest to southeast. It is located on the Yu ...
but no breeding records are known in at least 30 years in either. They range throughout most of the Arctic isles of Russia such as Novaya Zemlya
Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
, Severnaya Zemlya, New Siberian Islands
The New Siberian Islands ( rus, Новосиби́рские Oстрова, r=Novosibirskiye Ostrova; sah, Саҥа Сибиир Aрыылара, translit=Saña Sibiir Arıılara) are an archipelago in the Extreme North of Russia, to the north ...
, Wrangel Island
Wrangel Island ( rus, О́стров Вра́нгеля, r=Ostrov Vrangelya, p=ˈostrəf ˈvrangʲɪlʲə; ckt, Умӄиԓир, translit=Umqiḷir) is an island of the Chukotka Autonomous Okrug, Russia. It is the 91st largest island in the w ...
, Commander
Commander (commonly abbreviated as Cmdr.) is a common naval officer rank. Commander is also used as a rank or title in other formal organizations, including several police forces. In several countries this naval rank is termed frigate captain. ...
and Hall Islands
The Hall Islands are a group of two large atolls in the northern part of the state of Chuuk, Federated States of Micronesia. In the broader sense, a third and smaller atoll is included.
Nomwin, the western atoll, and Murilo, the eastern one, ...
.[
In North America, the breeding range has been known in modern times to include the ]Aleutians
The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a chain of 14 large vo ...
(i.e. Buldir and Attu) and much of northern Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...
, most frequently from the Arctic National Wildlife Refuge
The Arctic National Wildlife Refuge (ANWR or Arctic Refuge) is a national wildlife refuge in northeastern Alaska, United States on traditional Gwich'in lands. It consists of in the Alaska North Slope region. It is the largest national wildli ...
to Utqiaġvik, and more sporadically down along the coastal-western parts such as through Nome, Hooper Bay, the Yukon Delta National Wildlife Refuge
The Yukon Delta National Wildlife Refuge is a United States National Wildlife Refuge covering about in southwestern Alaska. It is the second-largest National Wildlife Refuge in the country, only slightly smaller than the Arctic National Wildlife R ...
, and rarely even south to the Shumagin Islands.[ The snowy owl may breed extensively in northern Canada, largely making its home in the ]Arctic Archipelago
The Arctic Archipelago, also known as the Canadian Arctic Archipelago, is an archipelago lying to the north of the Canadian continental mainland, excluding Greenland (an autonomous territory of Denmark).
Situated in the northern extremity of No ...
. Their Canadian breeding range can include broadly Ellesmere Island
Ellesmere Island ( iu, script=Latn, Umingmak Nuna, lit=land of muskoxen; french: île d'Ellesmere) is Canada's northernmost and third largest island, and the tenth largest in the world. It comprises an area of , slightly smaller than Great Br ...
up to Cape Sheridan
Cape Sheridan is on the northeastern coast of Ellesmere Island, Canada situated on the Lincoln Sea in the Arctic Ocean, on the mouth of Sheridan River, west bank. It is one of the closest points of land to the geographic North Pole, approx to the ...
, north coastal Labrador
, nickname = "The Big Land"
, etymology =
, subdivision_type = Country
, subdivision_name = Canada
, subdivision_type1 = Province
, subdivision_name1 ...
, the northern Hudson Bay
Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
, perhaps all of Nunavut
Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the '' Nunavut Act'' and the '' Nunavut Land Claims Agreement Act'' ...
(especially the Kivalliq Region), northeastern Manitoba
Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...
, most of northern mainland and insular Northwest Territories
The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
(including the delta of the Mackenzie River) and northern Yukon Territory
Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...
(where breeding is mostly confined to Herschel Island).[ Since breeding and distribution is very small, local and inconsistent in northern Europe, northern Canada and northern Alaska represent the core part of the breeding range for snowy owls along with several parts of northern and northeastern/coastal Russia.][
]
Regular wintering range
During the wintering, many snowy owls leave the dark Arctic to migrate to regions further south. Southern limits of the regular winter range are difficult to delineate given the inconsistency of appearances south of the Arctic.[ Furthermore, not infrequently, many snowy owls will overwinter somewhere in the Arctic through the winter, though seldom appear to do so in the same sites where they have bred.][ Due in no small part to the difficulty and hazardousness of observation for biologists during these harsh times, there is very limited data on overwintering snowy owls in the tundra, including how many occur, where they winter and what their ecology is at this season.][ The regular wintering range has at times been thought to include Iceland, Ireland and Scotland and across northern Eurasia such as southern Scandinavia, the ]Baltics
The Baltic states, et, Balti riigid or the Baltic countries is a geopolitical term, which currently is used to group three countries: Estonia, Latvia, and Lithuania. All three countries are members of NATO, the European Union, the Eurozone, ...
, central Russia, southwestern Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part ...
, Sakhalin
Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh ...
southern Kamchatka
The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and west ...
and, rarely, north China and sometimes the Altai Republic
The Altai Republic (; russian: Респу́блика Алта́й, Respublika Altay, ; Altai: , ''Altay Respublika''), also known as Gorno-Altai Republic, and colloquially, and primarily referred to in Russian to distinguish from the neighbour ...
.[ In North America, they occasionally regularly winter in the Aleutian island chain and do so broadly and with a fair amount of consistency in much of southern Canada, from ]British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...
to Labrador
, nickname = "The Big Land"
, etymology =
, subdivision_type = Country
, subdivision_name = Canada
, subdivision_type1 = Province
, subdivision_name1 ...
.[ Recent research has indicated that snowy owls regularly winter in several of the northern ]seas
This is a list of seas of the World Ocean, including marginal seas, areas of water, various gulfs, bights, bays, and straits.
Terminology
* Ocean – the four to seven largest named bodies of water in the World Ocean, all of which have "Ocean ...
during wintertime, following the leads of sea ice
Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's o ...
as perching sites and presumably hunting mostly seabird
Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same envir ...
s in polynya
A polynya () is an area of open water surrounded by sea ice. It is now used as a geographical term for an area of unfrozen seawater within otherwise contiguous pack ice or fast ice. It is a loanword from the Russian полынья (), which r ...
s. In February 1886, a snowy owl landed on the rigging of the Nova Scotia
Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland".
Most of the population are native Eng ...
steamship ''Ulunda'' on the edge of the Grand Banks of Newfoundland
The Grand Banks of Newfoundland are a series of underwater plateaus south-east of the island of Newfoundland on the North American continental shelf. The Grand Banks are one of the world's richest fishing grounds, supporting Atlantic cod, sword ...
, over from the nearest land. It was captured and later preserved at the Nova Scotia Museum
Nova Scotia Museum (NSM) is the corporate name for the 28 museums across Nova Scotia, Canada, and is part of the province's tourism infrastructure. The organization manages more than 200 historic buildings, living history sites, vessels, and speci ...
. Surprisingly, some studies have determined that after a high lemming year in North America, a higher percentage of snowy owls were using marine environments rather than inland ones.
Irruptive range
Large winter irruptions at temperate latitudes are thought to be due to good breeding conditions resulting in more juvenile migrants.[ These result in irruptions occurring further south than the typical snowy owl range in some years.] They have been reported, as well as in all northerly states in the contiguous states, as far south as the Georgia
Georgia most commonly refers to:
* Georgia (country), a country in the Caucasus region of Eurasia
* Georgia (U.S. state), a state in the Southeast United States
Georgia may also refer to:
Places
Historical states and entities
* Related to the ...
, Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...
, South Carolina
)''Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no)
, anthem = " Carolina";" South Carolina On My Mind"
, Former = Province of South Carolina
, seat = Columbia
, LargestCity = Charleston
, LargestMetro = ...
, nearly all the Gulf Coast of the United States
The Gulf Coast of the United States, also known as the Gulf South, is the coastline along the Southern United States where they meet the Gulf of Mexico. The coastal states that have a shoreline on the Gulf of Mexico are Texas, Louisiana, Missi ...
, Colorado
Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the ...
, Nevada
Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
, Texas
Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...
, Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...
, California and even Hawaii.[ In January 2009, a snowy owl appeared in Spring Hill, Tennessee, the first reported sighting in the state since 1987. Also notable is the mass southern migration in the winter of 2011/2012, when thousands of snowy owls were spotted in various locations across the United States. This was then followed by an even larger mass southern migration in 2013/2014 with the first snowy owls seen in Florida for decades. The nature of irruptions is less well-documented in Eurasia, in part due to the paucity of this owl in the European side, but accidental occurrence, presumably during irruptions, has been described in the ]Mediterranean
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...
area, France, Crimea
Crimea, crh, Къырым, Qırım, grc, Κιμμερία / Ταυρική, translit=Kimmería / Taurikḗ ( ) is a peninsula in Ukraine, on the northern coast of the Black Sea, that has been occupied by Russia since 2014. It has a p ...
, the Caspian part of Iran, Kazakhstan, northern Pakistan, northwestern India, Korea and Japan.[ Stragglers may too turn up as far south as the ]Azores
)
, motto =( en, "Rather die free than subjected in peace")
, anthem= ( en, "Anthem of the Azores")
, image_map=Locator_map_of_Azores_in_EU.svg
, map_alt=Location of the Azores within the European Union
, map_caption=Location of the Azores wi ...
and Bermuda.[
]
Habitat
Snowy owls are one of the best known inhabitants of the open Arctic tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
. Frequently, the earth in snowy owl breeding grounds is covered with moss
Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and ...
es, lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.[rocks. Often the species preferentially occurs in areas with some rising elevation such as hummocks, knolls, ]ridge
A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...
s, bluffs and rocky outcrops.[ Some of these rises in the tundra are created by glacial deposits.][ The ground is usually rather dry in tundra but in some areas of the southern tundra can also be quite ]marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found ...
y.[ Not infrequently, they will also use areas of varied ]coast
The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...
al habitat, often tidal flats
Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal f ...
, as a breeding site. Breeding sites are usually at low elevations, usually less than above sea level, but when breeding to the south in inland mountains, such as in Norway, they may nest at as high as .[ Outside the breeding season, snowy owls may occupy nearly any open landscape.][ Typically wintering sites are rather windswept with meager cover.][ These open areas can include coastal dunes, other ]coast
The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...
al spots, lakeshores, islands, moorland
Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland, nowadays, generall ...
s, steppe
In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes.
Steppe biomes may include:
* the montane grasslands and shrublands biome
* the temperate gras ...
s, meadow
A meadow ( ) is an open habitat, or field, vegetated by grasses, herbs, and other non- woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows may be naturally occurring or arti ...
s, prairie
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...
s, other extensive grassland
A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s and rather shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...
by areas of the Subarctic
The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of humid continental regions and covering much of Alaska, Canada, Iceland, the north of Scandinavia, Siberia, and the Cairngorms. Genera ...
. These may be favored due to their vague similarity to the flat openness of the tundra.[ Manmade open sites are now perhaps even more used than natural ones, often agricultural fields and ]rangeland
Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, sava ...
, as well as large areas of cleared forests. During irruption years when they are found in the northeastern United States, juveniles frequent developed areas including urban areas and golf course
A golf course is the grounds on which the sport of golf is played. It consists of a series of holes, each consisting of a tee box, a fairway, the rough and other hazards, and a green with a cylindrical hole in the ground, known as a "cup". ...
s, as well as the expected grassland
A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s and agricultural areas that older birds primarily use.[ On the plains of Alberta, observed snowy owls spent 30% of their time in stubble-fields, 30% in ]summer fallow Summer fallow, sometimes called fallow cropland, is cropland that is purposely kept out of production during a regular growing season. Resting the ground in this manner allows one crop to be grown using the moisture and nutrients of more than one c ...
, 14% in hayfield and the remainder of the time in pasture
Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or sw ...
, natural grasslands and slough
Slough () is a town and unparished area in the unitary authority of the same name in Berkshire, England, bordering west London. It lies in the Thames Valley, west of central London and north-east of Reading, at the intersection of the ...
s. The agricultural areas, large untouched by the farmers in winter, may have had more concentrated prey than the others in Alberta. Perhaps the most consistently attractive habitat in North America to wintering snowy owls in modern times may be airports, which not only tend to have the flat, grassy characteristics of their preferred habitats but also by winter host a particular diversity of prey, both pests
PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...
which rely on humans as well as wildlife attracted to the extensively grassy and marshy strips that dot the large airport vicinities. For example, Logan International Airport
General Edward Lawrence Logan International Airport , also known as Boston Logan International Airport and commonly as Boston Logan, Logan Airport or simply Logan, is an international airport that is located mostly in East Boston and partial ...
in Massachusetts
Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...
has relatively one of the most reliable annual populations known in the United States in winter.[ All ages spend a fair amount of their time over water in the ]Bering Sea
The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Am ...
, the Atlantic Ocean and even the Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
, mostly on ice floes.[ These marine and ocean-like freshwater areas were observed to account for 22–31% of habitat used in 34 radio-tagged American snowy owls over two irruptive years, with the tagged owls occurring a mean of from the nearest land (while 35–58% used the expected preferred habitats of grassland, pasture and other agricultural land).][
]
Behavior
Snowy owls may be active to some extent at both day, from dawn to dusk, and night.[ Snowy owls have been seen to be active even during the very brief winter daytime in the northern winter.][ During the Arctic summer, snowy owls may tend to peak in activity during the twilight that is the darkest time available given the lack of full nightfall.] Reportedly, the peak time of activity during summer is between 9:00 pm and 3:00 am in Norway.[Hagen, Y. (1960). ''The Snowy Owl on Hardangervidda in the Summer of 1959''. Papers of The Norwegian State Game Research. 2, No. 7.] The peak time of activity for those owls that once nested on Fetlar was reported between 10:00 and 11:00 pm. According to one authority, the least active times are at noon and midnight.[ As days become longer near autumn in Utqiaġvik, the snowy owls in the tundra become more active around nightfall and can often be seen resting during the day, especially if it is raining.][ During winter in ]Alberta
Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest T ...
, snowy owls were tracked in the daytime, despite being also active at night (as they were deemed too difficult to track). In the study, they were most active during 8:00–10:00 am and 4:00–6:00 pm and often rested mostly from 10:00 am to 4:00 pm. The owls were perched for 98% of observed daylight and seemed to time their activity to peak times for rodents. The variation of activity is probably in correspondence with their primary prey, the lemmings, and like them, the snowy owl may be considered cathermal. This species can withstand extremely cold temperatures, having been recorded in temperatures as low as minus 62.5 degrees Celsius
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The d ...
with no obvious discomfort and also withstood a 5-hour exposure to minus 93 degrees Celsius but may have struggled with oxygen consumption by the end of this period. The snowy owl has perhaps the second lowest thermal conduction
Conduction is the process by which heat is transferred from the hotter end to the colder end of an object. The ability of the object to conduct heat is known as its ''thermal conductivity'', and is denoted .
Heat spontaneously flows along a te ...
to the plumage on average of any bird after only the Adelie penguin (''Pygoscelis adeliae'') and rivals the best insulated mammals, such as Dall sheep (''Ovis dalli'') and Arctic fox
The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in ...
, as the best insulated polar creature.[ Presumably as many as 7 rodents would need to be eaten daily to survive an extremely cold winter's day.][ Adults and young both have been seen to shelter behind rocks to shield themselves from particularly harsh winds or storms.][ Snowy owls often spending a majority of time on the ground, perched mostly on a slight rise of elevation.][ It has been interpreted from the morphology of their skeletal structure (i.e. their short, broad legs) that snowy owls are not well-suited to perching extensively in trees or rocks and prefer a flat surface to sit upon.][ However, they may perch more so in winter though do so only mainly when hunting, at times on hummocks, ]fence
A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or netting. A fence differs from a wall in not having a solid foundation along its whole length.
...
posts, telegraph poles by roads, radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a tr ...
and transmission tower
A transmission tower, also known as an electricity pylon or simply a pylon in British English and as a hydro tower in Canadian English, is a tall structure, usually a steel lattice tower, used to support an overhead power line.
In electrical ...
s, haystacks, chimney
A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typ ...
s and the roofs of houses and large buildings.[ Rocks may be used as perches at times in all seasons.][ Though often relatively sluggish owls, like most related species, they are capable of sudden dashing movements in various contexts.][ Snowy owls can walk and run quite quickly, using outstretched wings for balance if necessary.][ This owl flies with fairly rowing wingbeats, occasionally interrupted by gliding on stretched wings. The flight is fairly buoyant for a ''Bubo'' owl.][ When displaying, the male may engage in an undulating flight with interspersed wingbeats and gliding in a slight dihedral, finally dropping rather vertically to the ground.][ They are capable for swimming but do not usually do so. Some seen to be swimming were previously injured but young have been seen to swim into water to escape predators if they cannot fly yet. They will also drink when unfrozen water is available.][ Snowy owl mothers have been observed to preen their young in the wild, while pairs in captivity have been observed to allopreen.][ In the period leading up to breeding, snowy owls switched regularly between searching (for nesting grounds) and loafing, often searching less when snow cover was less extensive.
Snowy owls will fight with conspecifics in all seasons occasionally but this is relatively infrequent during breeding and rarer still during winter. Dogfights and talon interlocking may ensue if the fight between two snowy owls continues to escalate.][ A study determined that snowy owls are able to orient the whitest parts of their plumage towards the sun, spending about 44% of time oriented as such during sunny days and much less on cloudy days. Some authors interpret this as a presumed signal to conspecifics, but ]thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperatur ...
could also be a factor. It is known that during winter in Alberta that female snowy owls are territorial towards one another and may not leave an area for up to 80 days but males are nomadic, usually only staying 1–2 days in an area (seldom to 3–17 days). The females spent on average seven times as long in a given area than did males. During threat displays, individuals will lower the front of the body, stretch the head low and forward, with partially extended wings and feathers on the head and raise their back.[ If continuously threatened or cornered, the posture in the threat display may become still more contoured and, if pressed, the owl will like back and attempt to slash with its large talons. The threat displays of males are generally more emphatic than those of females.][ Although snowy owls have been considered as semi-colonial, they do not appear to fit this mold well. Nesting sites can be loosely clustered but this is a coincidental response to concentrated prey and each pair tends to be somewhat intolerant of each other.] During winter, snowy owls are usually solitary but some aggregations have been recorded, especially nearer the Arctic when more narrow food selection can lead to up to 20–30 owls gathering in an area of about . Congregations were also recorded in the winter in Montana, where 31–35 owls wintered in a area, owls mostly grouped in loose aggregations of 5–10 owls each or occasionally side-by-side or about apart.[ In extreme cases in Utqiaġvik, the owls may have exceptionally close active nests that may be down to only apart.]