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Northern hawk-owl

The Northern hawk-owl (Surnia ulula) is a medium-sized diurnal owl species native to the boreal forests of North America and Eurasia, characterized by its long tail, yellow eyes, and heavily barred underparts, with a length of 15–17 inches (38–43 cm) and a wingspan of about 33 inches (84 cm).^[1]^[2] It features a whitish face framed by dark parentheses-like markings, no ear tufts, and upperparts in shades of dark gray to brown with white spots, giving it a hawklike appearance despite its owl classification.^[2] This owl inhabits open coniferous or mixed forests, often near marshes or burned areas that provide suitable perches and prey access, primarily across Alaska, Canada, and northern Eurasia.^[3]^[1] Unlike most owls, the Northern hawk-owl is predominantly active during daylight hours, perching upright on high solitary trees to scan for prey, which it detects visually from up to half a mile away or by sound even under a foot of snow.^[2]^[3] It hunts by making swift aerial dives or hovering briefly before capturing small mammals such as voles and mice, which form the bulk of its diet in summer, supplemented by birds like ptarmigan or grouse in winter, as well as occasional squirrels, insects, or amphibians.^[1]^[3] The species exhibits nomadic tendencies, irrupting southward into the northern United States during periods of prey scarcity in its core boreal range, though it does not undertake regular migrations.^[2]^[1] Breeding occurs in spring, with pairs forming temporarily for one season; the female lays 3–13 eggs (typically 5–7) in abandoned woodpecker cavities, decayed tree hollows, or occasionally old nests, incubating them for 25–30 days while the male provides food.^[1]^[3] Nestlings fledge after 20–35 days, and the species caches excess food in tree crevices for later consumption.^[3] Its vocalizations include a whistling "ki-ki-ki" call reminiscent of a kestrel, used in courtship displays involving flight and calling.^[1] The Northern hawk-owl's global breeding population is estimated at around 200,000 individuals, classified as of low conservation concern, though populations fluctuate with small mammal cycles and face threats from habitat loss due to clearcutting in boreal forests.^[3] Its adaptability to disturbed habitats like burned forests aids resilience, but irruptive movements can lead to human-wildlife conflicts or increased vulnerability during southern wanderings.^[3]

Taxonomy and systematics

Etymology and classification

The northern hawk-owl bears the scientific name Surnia ulula, the sole species in its genus within the family Strigidae, the true owls, and subfamily Striginae.^[4] The genus Surnia was established in 1805 by the French zoologist André Marie Constant Duméril; its etymology is uncertain and may derive from a Latin term for a type of owl or have been arbitrarily coined.^[5] The specific epithet ulula derives from Latin, denoting a "screech owl" or onomatopoeically mimicking the bird's characteristic yapping call.^[5] The common name "hawk-owl" highlights its hawk-like morphology, including a long tail and pointed wings, as well as its diurnal hunting behavior atypical among owls.^[6] Historically, the species was first described by Carl Linnaeus in 1758 as Strix ulula in the tenth edition of Systema Naturae, placing it among the earless owls in the broad genus Strix.^[4] Subsequent taxonomic revisions in the 19th century separated it into the distinct genus Surnia, reflecting its unique traits. Recognition of subspecies—S. u. ulula (Eurasian), S. u. caparoch (North American), and S. u. tianschanica (Asian)—was formalized in the early 20th century through morphological analyses, with caparoch described by Harry C. Oberholser in 1912 based on size and plumage differences.^[4] Molecular phylogenetic studies have clarified its position within Strigidae, revealing Surnia ulula as sister to a clade containing the pygmy owls of genus Glaucidium, rather than closer boreal species like the boreal owl (Aegolius funereus).^[7] This placement underscores the extensive paraphyly in the family and highlights the northern hawk-owl's evolutionary divergence, potentially linked to its diurnal adaptations.^[7]

Subspecies

The Northern hawk-owl (Surnia ulula) is classified into three recognized subspecies, distinguished primarily by morphological variations in size, plumage coloration, and barring patterns, which are thought to reflect adaptations to local environmental conditions across their Holarctic range.^[4] The nominate subspecies, S. u. ulula, inhabits northern Eurasia from Scandinavia eastward to Kamchatka and Sakhalin; it is the largest form, measuring up to 43 cm in length, with paler overall plumage featuring reduced white spotting and less dense barring on the underparts compared to other subspecies.^[4] This paler tone likely aids camouflage in the lighter, snowier Eurasian boreal landscapes.^[4] In central and eastern Asia, the subspecies S. u. tianschanica occupies montane forests from southeastern Kazakhstan through Kyrgyzstan, Tajikistan, northeastern Uzbekistan, Afghanistan, northern Pakistan, northern India, western and northern China, and northern Mongolia; it is smaller than the nominate, averaging 36-40 cm, and exhibits darker plumage with more extensive barring and streaking, particularly on the ventral surfaces, suited to denser, shadier coniferous habitats.^[4] The North American subspecies, S. u. caparoch, ranges from Alaska across northern Canada to Newfoundland and Labrador, extending south to northern British Columbia, Alberta, Saskatchewan, Manitoba, and Minnesota; it is intermediate in size (38-42 cm) and darker than the nominate, with increased pigmentation and barring similar to tianschanica, reflecting adaptations to the varied boreal forests of the Nearctic.^[4] These subspecies show marked individual variation, which can obscure boundaries, but geographic exclusivity is generally maintained except in potential overlap zones like Beringia, where interbreeding between Eurasian and North American forms may occur.^[4] Morphological distinctions are supported by traditional taxonomic assessments, while molecular studies indicate limited genetic differentiation among populations, suggesting recent divergence and ongoing gene flow across the species' range.^[8] No subspecies are considered extinct.^[4]

Physical characteristics

Morphology and plumage

The northern hawk-owl (Surnia ulula) is a medium-sized owl measuring 36–45 cm in length, with a wingspan of 71–81 cm and a body weight ranging from 240–454 g.^[9]^[10] Females exhibit reversed sexual size dimorphism, being approximately 10–20% larger and heavier than males, though this difference is not strongly pronounced compared to other owl species.^[11]^[6] Distinctive structural features include a long, tapered, and barred tail reminiscent of a hawk's, short pointed wings suited for agile maneuvers, piercing yellow eyes, and a white facial disk outlined by bold black borders without ear tufts; the crown features prominent white spots for camouflage.^[9]^[10]^[12] The legs and feet are fully feathered down to the strong, curved talons adapted for grasping small mammals and birds.^[12] Plumage in adults is predominantly dark brown on the upperparts with dense white spotting, while the underparts are pale with fine brown streaking or barring; juveniles display a duller grayish-brown overall with reduced white markings and more uniform barring, gradually acquiring adult patterns.^[9]^[13] These birds undergo an annual complete molt, replacing nearly all flight feathers (primaries, secondaries, and rectrices) in a sequence that supports their active lifestyle.^[14] The owl's morphology emphasizes adaptations for diurnal activity in boreal forests, featuring a streamlined oval body that facilitates powerful, falcon-like wingbeats and low glides during hunting flights.^[9]^[6] Plumage variations among subspecies are slight to moderate, primarily in spotting density and overall tone.^[11]

Vocalizations

The Northern hawk-owl (Surnia ulula) employs a diverse repertoire of vocalizations for communication, including territorial defense, alarm signaling, contact maintenance, courtship, and parental interactions. These calls are typically delivered from prominent perches in open boreal habitats, allowing for effective transmission over distances.^[9]^[15] Territorial calls, primarily produced by males, consist of a series of rapid, repetitive hoots often rendered as "ki-ki-ki-ki-ki" or a whistling "keck-keck-keck," repeated up to 12 times in quick succession and used year-round to defend breeding and foraging areas.^[16]^[1] These calls can escalate in intensity during confrontations with rivals, sometimes incorporating sleeking of facial feathers and direct stares.^[17] Alarm and contact calls include sharp, high-pitched notes such as a harsh screech followed by repeated raspy "kip" or "keek" sounds, emitted in response to threats like approaching predators or intruders.^[18] Fledglings produce begging calls described as a high-pitched "tsi-tsi-tsi" or scream-like "see-see-see" to solicit food from parents.^[15] Softer "ugh" or "uih" chirps serve as contact calls between mated pairs and between adults and young to maintain proximity.^[13] During courtship, males deliver a distinctive soft purring trill, a rapid melodious series of up to 14 seconds duration resembling a distant motorboat, consisting of 11–15 notes per second; this advertises potential nest sites, particularly at dawn and dusk.^[15] Females respond with a similar but shorter, higher-pitched, and hoarser version, less consistent in rhythm.^[19] Subspecies variations exist, with calls in the Asian subspecies S. u. tianschanica exhibiting a lower overall pitch compared to North American forms.^[19] In breeding contexts, these vocalizations facilitate pair formation and coordination during nesting.^[19]

Distribution and habitat

Geographic range

The northern hawk-owl (Surnia ulula) exhibits a holarctic distribution, primarily occupying boreal forests across northern Eurasia and North America. In Eurasia, the species is resident from Scandinavia, including Norway, Sweden, and Finland, eastward through Siberia to Kamchatka, Sakhalin, and Chukotka, generally between approximately 45°N and 70°N latitude.^[15] In North America, it breeds from Alaska eastward to Newfoundland, with a core range between about 50°N and 65°N latitude, extending south at the periphery to northern Minnesota and Maine.^[1]^[2] Although largely non-migratory, the northern hawk-owl is nomadic and prone to irruptive movements, particularly southward invasions triggered by fluctuations in prey populations such as voles. Notable examples include widespread irruptions across North America during the 2005–2006 winter, when crashes in northern vole populations drove birds into southern Canada and the northern United States, and the 2024–2025 winter, the largest in two decades, with significant numbers observed in northeast Minnesota.^[20]^[21] These movements are irregular and depend on local food availability, with the species otherwise remaining within its boreal breeding grounds year-round.^[10] Vagrant records highlight the species' potential for wider dispersal, including sightings in the United Kingdom and Japan, often associated with extreme irruptions or weather events. Recent observations from the 2020s, informed by citizen science platforms like eBird, indicate increased sightings during irruptions in parts of North America, potentially linked to climate-driven changes in boreal habitats and prey dynamics, though the species' core distribution remains stable.^[22] Climate models predict further range alterations, including potential contractions in northern latitudes due to shifting forest zones.^[22] Global population estimates for the northern hawk-owl range from 100,000 to 499,999 mature individuals, based on 2020 assessments, with a more recent 2024 estimate of approximately 250,000 individuals globally; regional breakdowns indicate approximately 87,000 mature individuals in North America and 20,800–92,400 breeding pairs in Europe.^[22]^[23] The overall trend is considered stable, though numbers fluctuate with prey cycles and habitat conditions.^[22]

Habitat preferences

The northern hawk-owl inhabits open boreal forests, including taiga landscapes, muskegs, and areas with scattered conifers such as spruce (Picea) and pine, often favoring forest edges, glades, and second-growth mixed woodlands.^[24] It avoids dense, old-growth coniferous forests that limit visibility and perch availability, preferring instead moderately open canopies with shrub cover to facilitate hunting and movement.^[12] Burned-over areas are particularly suitable, providing snags and increased prey access, with the species colonizing such sites within 1–2 years post-fire and achieving peak densities in the second year.^[24] Key habitat requirements include elevated perches, such as tall snags or solitary trees, for scanning open ground, along with proximity to prey-abundant meadows, marshes, or clearings.^[2] These features support the owl's diurnal hunting strategy in landscapes at elevations from sea level to approximately 2,650 m.^[22] The species selects areas with a mix of coniferous and deciduous elements, including tamarack (Larix laricina) bogs and riparian zones, where moderate canopy and shrub density maintain openness.^[24] Habitat use varies seasonally, with breeding occurring in open boreal and tundra-edge forests during summer, while winter occupancy shifts to sheltered coniferous stands within the breeding range or southward during irruptions.^[2] Nomadic movements are driven by prey availability, but the owl remains largely resident in suitable boreal environments year-round.^[22] Subspecies exhibit geographic variation in habitat, with the nominate S. u. ulula occupying wetter taiga across northern Eurasia and S. u. tianschanica in drier, montane steppes of central Asia.^[4]

Behavior and ecology

Daily activity patterns

The northern hawk-owl (Surnia ulula) exhibits a predominantly diurnal lifestyle, remaining active primarily from dawn to dusk, which sets it apart from most owl species that are nocturnal.^[16]^[17]^[3] Its activity peaks shortly after sunrise and before sunset, with observations showing higher rates of movement and prey delivery during these crepuscular periods, particularly in northern latitudes where extended daylight supports such rhythms.^[25] While minimal nocturnal activity occurs under normal conditions, the owl may extend hunting into nighttime during winter or irruptive migrations when prey is scarce.^[16]^[3] During active periods, the northern hawk-owl frequently perches upright on exposed, elevated branches or treetops in open areas adjacent to dense forests, using these vantage points to scan for prey with keen visual acuity.^[12]^[17]^[3] It moves between perches via low, direct flights characterized by rapid wingbeats and occasional glides, maintaining an alert posture that resembles a hawk's.^[12] At night, it transitions to resting by roosting in dense foliage or concealed cover to avoid predators, flattening its plumage and standing erect if threatened.^[12]^[2] These patterns are facilitated by diurnal adaptations, including forward-facing yellow eyes and a reduced facial disk that enhance binocular vision and daytime prey detection, contrasting with the asymmetric ears of nocturnal owls.^[16]^[26] Its pointed wings and long tail further support agile, hawk-like aerial maneuvers suited to daylight foraging in boreal environments.^[16] The northern hawk-owl (Surnia ulula) is generally solitary throughout the year, maintaining low population densities in its boreal forest habitat.^[3] Individuals defend territories year-round, with home ranges typically spanning 100–500 hectares (1–5 km²), though exact territory boundaries are not always sharply defined.^[27] Defense involves vocalizations and aerial displays, such as wing-clapping flights, with males being particularly vocal during territorial maintenance.^[28]^[12] Northern hawk-owls form monogamous pairs that typically bond in late winter prior to breeding.^[28]^[29] Even during irruptive movements southward in response to prey shortages, these owls exhibit minimal flocking and remain largely solitary or paired, showing tolerance for conspecifics but avoiding dense groups.^[3]^[29] Aggressive interactions occur when territories are threatened, with individuals chasing intruders, including larger species like the great gray owl (Strix nebulosa).^[29] Juveniles disperse from natal areas approximately 1–2 months after fledging, typically around 2.5–3 months of age, as parents reduce provisioning and young become independent hunters.^[1]^[30]^[31] Communication includes both vocal and visual signals; for example, harsh screeches serve as alarm calls, while territorial disputes may involve visual displays such as tail-fanning accompanied by loud squawking to deter nearby threats like common ravens (Corvus corax).^[18]^[17]

Reproduction

Breeding season and mating

The breeding season of the northern hawk-owl (Surnia ulula) typically spans from late March to June, with egg-laying commencing around April in southern portions of its range and extending into early June farther north.^[12] This timing is closely tied to fluctuations in prey abundance, particularly cyclic populations of voles, which prompt breeding only when food resources are sufficient to support reproduction.^[32] Courtship begins with males performing aerial displays, circling in flight with stiff wings while emitting calls to attract females, followed by landing on prominent perches to continue vocalizing.^[3] Pairs engage in duetting calls and bowing behaviors, with males providing courtship feeding by delivering prey to the female, who ultimately selects the nesting site.^[1]^[17] Females lay 3 to 13 eggs per clutch, with an average of 6 to 7, and eggs are typically deposited at intervals of about 1.6 to 2 days.^[32] Clutch sizes often increase to 8 to 13 eggs during years of high vole abundance, reflecting the species' opportunistic response to food availability.^[32] Northern hawk-owls exhibit irruptive breeding patterns, where nomadic pairs may delay reproduction or relocate to areas with plentiful prey if vole populations are low, resulting in variable breeding densities across years.^[33] They generally produce one brood per year, though reproductive output, measured as fledglings per nest (ranging from 1 to 7), correlates strongly with local rodent cycles.^[29]

Nesting and parental care

Northern hawk-owls do not construct nests but utilize existing cavities, typically in snags or abandoned woodpecker holes, such as those made by northern flickers, at heights of 3 to 12 meters above the ground.^[3]^[1] These sites are often located in open coniferous or mixed forests near edges or burned areas, providing proximity to hunting grounds while offering protection.^[12] In some regions, they may also occupy old stick nests of larger birds like crows or hawks, or even artificial nest boxes.^[15] The female lays white eggs measuring approximately 38 by 30 mm, with clutches typically ranging from 5 to 7, though they can vary from 3 to 13 depending on prey abundance.^[1]^[15] Incubation begins with the first egg and lasts 25 to 30 days, performed solely by the female while the male provisions her with food at the nest site.^[3]^[12] Upon hatching, the altricial chicks are helpless and covered in white down, requiring constant brooding by the female for the first 10 to 18 days.^[1]^[15] The young open their eyes around day 10 and begin calling before emerging from the eggshells, which are either eaten or removed by the adults.^[12] They fledge after 20 to 35 days, often climbing the nest tree beforehand, and remain dependent on parents for up to three months while learning to hunt.^[3]^[27] During the nestling period, the male delivers most of the food to the female, who feeds the chicks initially; after about two weeks, both parents participate in provisioning, with the male continuing to supply the majority of prey.^[1]^[12] This biparental care supports chick survival, though food scarcity can lead to nest abandonment.^[15]

Diet and foraging

Prey selection

The northern hawk-owl primarily targets small mammals, which constitute 70-90% of its diet across much of its range, with voles of the genus Microtus (typically weighing 20-100 g) serving as the staple prey due to their abundance and ease of capture.^[3] In regions like Fennoscandia, pellet analyses indicate that voles can account for 93-96% of prey biomass during the breeding season, reflecting a strong specialization on these high-protein microtines to meet energetic demands for reproduction.^[34] However, in the Nearctic boreal forest, the diet shows greater diversity, with voles comprising only 20-30% of biomass and juvenile snowshoe hares (Lepus americanus) contributing 40-50% during cyclic peaks in hare populations.^[35] Birds form a secondary but important component, especially in winter when small mammals may become scarce under snow cover; examples include ptarmigan (Lagopus spp.) and sparrows (Passeriformes), making up approximately 20% of the diet in such periods.^[3]^[16] Secondary prey items include insects like beetles during summer months, as well as occasional amphibians and reptiles, which supplement the diet when rodents are plentiful but provide variety in warmer seasons.^[12] The largest recorded prey is the snowshoe hare, with individuals up to 1 kg occasionally taken, particularly juveniles that are more manageable for the owl's size.^[36] Seasonal shifts in prey selection are pronounced, with a mammal-dominated diet during the breeding season to support high protein requirements for egg production and chick rearing, transitioning to increased avian prey in winter scarcity.^[16] Regional and subspecific variations further influence composition; for instance, the Nearctic subspecies S. u. caparoch exhibits less reliance on voles and greater use of hares due to local prey cycles, whereas Palaearctic populations maintain a more vole-centric diet.^[35] Pellet studies from the 1990s, including analyses of over 300 prey items from nesting pairs, underscore these patterns, revealing up to 80% vole biomass in vole-abundant systems to fulfill nutritional needs during reproduction.^[34]

Hunting techniques

The northern hawk-owl primarily employs a perch-hunting strategy, scanning for prey from elevated vantage points such as treetops or posts, where it adopts a forward-leaning posture to enhance its field of view. Upon detecting movement, it launches a rapid dive or glide toward the target, often covering distances up to several hundred meters with high maneuverability, capturing small mammals or birds on the ground or in low vegetation before returning to a perch to consume the prey. This visual-based predation allows it to spot potential targets, such as voles, from up to 0.8 kilometers away, relying on daytime acuity rather than the auditory cues typical of nocturnal owls.^[3]^[1]^[30]^[28] For more evasive prey in open habitats, the northern hawk-owl shifts to active pursuit, flying low over the terrain or briefly hovering kestrel-like before dropping onto the target with surprise, which enables captures in flight or from dense cover where perch access is limited. This adaptable approach complements its perch method, allowing exploitation of varied boreal landscapes like forest edges or burned areas.^[28]^[10] Northern hawk-owls frequently cache surplus prey to sustain energy demands, particularly during breeding or periods of abundance, storing kills in tree branches, cavities, or near nests for retrieval within days; observations indicate they cache over 90% of excess items in winter, preserving them frozen in northern climates. This behavior, documented in nesting pairs, supports chick provisioning and buffers against prey scarcity.^[37]^[38]^[16]^[39] Key adaptations enhance these techniques, including forward-facing eyes providing binocular vision for precise depth perception during dives, and the absence of fringed wing feathers for silent flight, as its diurnal habits prioritize speed over stealth. Its hawk-like morphology and behavior further facilitate aerial pursuits, distinguishing it from typical owls.^[3]^[28]^[10]

Conservation

Population status

The Northern hawk-owl (Surnia ulula) is classified as Least Concern on the IUCN Red List, with a global population estimated at 100,000–499,999 mature individuals and an overall stable trend as of the 2021 assessment.^[22] This status reflects its wide distribution across boreal forests in North America, Europe, and Asia, where it benefits from large habitat extents despite local fluctuations tied to prey availability.^[22] In North America, the population is estimated at approximately 130,000 individuals, including about 87,000 mature adults, based on 2020 Partners in Flight assessments.^[22] Breeding densities are generally low and variable, ranging from 0 to 6 pairs per 100 km² in areas like the Yukon, with higher concentrations up to 20 pairs per 100 km² recorded in parts of Europe during peaks in small rodent populations.^[29] These densities underscore the species' nomadic nature, as breeding pairs concentrate in regions with abundant voles and other small mammals.^[20] Population monitoring through platforms like eBird and Christmas Bird Counts reveals cyclical irruptions every 3–10 years, driven by multi-year fluctuations in rodent prey cycles, which cause southward movements into southern Canada and the northern United States during low-prey winters.^[40] In the wild, individuals typically live 10 years on average, with a maximum recorded longevity of 16.2 years.^[29]^[41] Recent analyses from 2011–2021 indicate no major global declines, though eBird data show localized decreases in relative abundance at southern range edges, potentially linked to habitat shifts, while core boreal areas remain stable.^[40]

Threats and management

The northern hawk-owl faces primary threats from habitat loss due to logging in its boreal forest range, where clear-cutting reduces availability of nest sites in dead snags and hunting perches in open areas. Unsustainable forestry practices disrupt the semi-open coniferous and mixedwood habitats preferred by the species, potentially limiting breeding success and foraging efficiency.^[22]^[28]^[42] Climate change exacerbates these pressures by predicting substantial contraction of boreal forests and alterations to small mammal cycles, particularly voles, which form the owl's primary prey base and drive population fluctuations. During irruptive movements triggered by prey crashes, individuals are vulnerable to starvation if food remains scarce in new areas and to predation by larger raptors such as great horned owls. Secondary threats include anticoagulant rodenticide poisoning through contaminated prey and collisions with vehicles and trains, which have been documented as causes of mortality.^[22]^[43] Conservation management emphasizes snag retention and leaving residual trees in clear-cut areas to maintain nesting and perching opportunities, with modified logging practices—such as creating smaller cuts under 100 hectares mixed with old-growth forest—benefiting hunting habitats. The species is protected within numerous Important Bird and Biodiversity Areas (IBAs), including national parks like Denali, covering a significant portion of its range. Ongoing research, including banding programs by the Canadian Wildlife Service since the 1980s, monitors irruptions and movements to inform adaptive strategies, though data gaps persist for Asian populations where monitoring is less comprehensive.^[22]^[28]^[30]^[42]

Human interactions

Use in falconry

The northern hawk-owl has occasionally been used in falconry practices in Scandinavia, where it is valued for pursuing small game.^[22] Capture is restricted to wild birds during irruptive years when populations temporarily increase southward, with low overall take rates to minimize population impacts. Its speed and agility, comparable to that of a merlin, make it effective for targeting voles and quail, but ethical guidelines emphasize sustainable sourcing and welfare.^[22]

Cultural and symbolic roles

In northern indigenous cultures, owls, including the boreal-dwelling Northern hawk-owl (Surnia ulula), hold varied symbolic meanings tied to guidance, morality, and the spirit world. Among the Inuit, owls are viewed as sources of help and direction, appearing in traditional stories that convey lessons about consequences and fortune; one tale describes an owl seeking a lemming for dinner, only for the lemming to trick the owl with flattery into dancing and allowing escape, after which the owl is scolded by its mate for trusting flatterers.^[44]^[45] These narratives position owls as moral actors in the natural and supernatural realms, reflecting their role as intermediaries between humans and the environment. The Sami people of northern Scandinavia regard owls as bringers of good fortune, associating them with positive omens in their traditional worldview, which emphasizes harmony with the Arctic landscape where the Northern hawk-owl resides.^[46] In broader northern European folklore, owls symbolize vigilance and the uncanny, often linked to witchcraft due to their elusive behaviors and piercing calls.^[47] In modern contexts, the Northern hawk-owl features prominently in wildlife art, inspiring paintings and illustrations that capture its long-tailed, barred plumage and alert yellow eyes as emblems of boreal resilience.^[48] It appears in documentaries on owl adaptations and northern ecosystems. During irruption events in the 2020s, when food shortages drive southward movements, the bird's rare appearances have sparked widespread interest among conservationists and the public, symbolizing the dynamic adaptability of wildlife in changing northern climates, including a notable irruption in winter 2024–2025 with sightings as far south as Minnesota and Michigan.^[49]^[50]^[51]

References

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This long-tailed owl perched upright at the top of a spruce. Rather hawklike in both appearance and behavior, it often hunts by day.At a Glance · Range & Identification · Behavior
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The Northern Hawk Owl looks like an owl but behaves like a hawk, with an oval body, yellow eyes, and dark parentheses. It hunts by daylight and can be spotted ...
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Northern Hawk Owl Life History - All About Birds
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S. u. ulula (Linnaeus, 1758). Includes Strix funerea Linnaeus, 1758; Ulula flammeata Frisch, 1766; Strix nisoria Meyer, 1810; S.
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The study reveals extensive paraphyly in owl genera, suggesting Athene, Otus, Asio, Megascops, Bubo, and Strix are paraphyletic, while Ninox and Glaucidium are ...
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Northern Hawk Owl I Owl Research Institute
FAMILY: Strigidae. CLOSEST RELATIVE: Northern Pygmy Owl. . NORTHERN HAWK OWL SIZE: . Height: Males 36-39 cm (14.1-15.3 in), Females 36-39 cm (14.1-15.3 in)Missing: classification | Show results with:classification
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Plumages, Molts, and Structure - Northern Hawk Owl - Surnia ulula
Northern Hawk Owls have 10 full-length primaries, 15 secondaries (including 3 tertials), and 12 rectrices; owls are diastataxic.
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Surnia ulula (northern hawk owl) - Animal Diversity Web
Scientific Classification ; Class, Aves birds ; Order, Strigiformes owls ; Family, Strigidae typical owls ; Genus, Surnia hawk-owls.
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While the northern hawk owl (Surnia ulula) shares many characteristics with smaller hawks, from its long, tapered tail and facial feathers to its diurnal ...Missing: size weight adaptations scientific sources
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Moult and Breeding of Captive Northern Hawk Owls Surnia ulula
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Oct 29, 2020 · The Northern Hawk Owl is a medium owl with no ear-tufts, a whitish face, long pointed wings, and a dark grey to dusky greyish-brown upperparts. ...Missing: facts | Show results with:facts
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The northern hawk owl (Surnia ulula) is a fairly common bird of the boreal forest in Alaska. It is, however, subject to population fluctuations and may at ...Missing: etymology | Show results with:etymology
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In captivity, both male and female react to calls or sight of rivals with Screeching Calls; rivals confront each other, sleeking face plumage and staring (Cramp ...
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A bird of boreal forests, the Northern Hawk Owl behaves like a hawk but looks like an owl. Its oval body, yellow eyes, and round face enclosed by dark ...Missing: facts | Show results with:facts
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Sound selections for Northern Hawk Owl can be found in the Audio Gallery, or see the full catalog of Northern Hawk Owl sound at Macaulay Library.Missing: analysis | Show results with:analysis
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... 70 meters, which can improve its hunting success. ... Without question, more data are needed on the status and ecology of the Northern Hawk Owl in Minnesota and ...
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This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence ...Missing: subspecies formalized 20th
[23]
Habitat - Northern Hawk Owl - Surnia ulula - Birds of the World
Favors open areas with suitable perches: muskegs, scrubby spruce (Picea) growths, forest glades, second-growth mixed hardwood and conifer woodlands, tamarack ( ...
[24]
[PDF] Diet, diel activity pattern and prey handling of nesting hawk owls ...
2014). This is also the case for the northern hawk owl (Surnia ulula) hereafter termed hawk owl. ... Hawk owls are diurnal, which is beneficial at northern ...
[25]
Early evolution of diurnal habits in owls (Aves, Strigiformes ... - PNAS
Mar 28, 2022 · Owl species exhibiting a predominantly diurnal activity pattern are rare, with only the northern hawk owl (Surnia ulula), burrowing owl (Athene ...
[26]
Surnia ulula - Northern Hawk Owl - NatureServe Explorer
Kingdom: Animalia ; Phylum: Craniata ; Class: Aves ; Order: Strigiformes ; Family: Strigidae.
[27]
Northern Hawk Owl - American Bird Conservancy
The Northern Hawk Owl, also known as the Canadian Owl or Hudsonian Hawk Owl, is one of the few members of its family that are active during the day.Missing: hybridization Beringia
[28]
Demography and Populations - Northern Hawk Owl - Surnia ulula
Anecdotal evidence suggests that populations have declined since the late 1800s and early 1900s, but there are few data to confirm this. Numbers fluctuate ...
[29]
Northern Hawk Owl - Montana Field Guide
Order - Owls - Strigiformes. Family - Owls - Strigidae. Species - Northern Hawk Owl - Surnia ulula. Northern Hawk Owl - Surnia ulula. 1 / 4. Northern Hawk Owl.Missing: classification | Show results with:classification
[30]
Resident Raptors: A Chronology of the Northern Hawk Owls at ...
The wide-open spaces punctuated with plenty of tall perches, bring in the ... On April 25, both adult Northern Hawk Owls were observed both perched on snags in ...Missing: height | Show results with:height
[31]
"Resource Partitioning in Breeding Populations of Marsh Hawks and ...
Though northern harriers and short-eared owls appear to have a high degree of niche overlap, this study showed that where eight individual pairs of the two ...Missing: territory | Show results with:territory
[32]
[PDF] Resource Partitioning in Breeding Populations of Marsh Hawks and ...
The home range of each harrier pair overlapped substantially with that of an owl pair. Percent habitat overlap for hawk-owl pairs varied from 39 percent to.
[33]
Breeding - Northern Hawk Owl - Surnia ulula - Birds of the World
Clutch Size. Three to 13, usually 7 (see Appendix 2). Average clutch size 6–10, sometimes increasing to 8–13 in good vole years. Egg-Laying. Mean laying ...
[34]
Hawk owl irruptions: spatial and temporal variation in rodent ...
Nov 19, 2022 · The hawk owl has a Holarctic distribution in the northern boreal forests, where it breeds in peak rodent years (Mikkola 1983; Cramp 1985; ...
[35]
[PDF] Northern Hawk-owls in the Nearctic Boreal Forest
Feb 1, 1995 · Abstract. We studied hawk-owls in the southwestern Yukon, Canada, from 1987-1993. Most information on hawk-owls originates from studies in ...
[36]
Northern Hawk-Owls in the Nearctic Boreal Forest: Prey Selection ...
Estimates of prey densities by live-trapping revealed that hawk-owls strongly prefer voles over snowshoe hares and squirrels.
[37]
Northern Hawk-owl | The Peregrine Fund
The Northern Hawk-owl is an owl with a 14-15 inch body, 2.5-3 ft wingspan, and 9-12 oz weight. It has yellow eyes, a dark head with white spots, and a dark ...Missing: subspecies | Show results with:subspecies
[38]
[PDF] Winter Prey Caching by Northern Hawk Owls in Minnesota
We provided prey to four individual. Northern Hawk Owls in wintering areas in northeast- ern Minnesota during 2001 and 2005 and observed their ...
[39]
[PDF] Food Caching Behavior of Nesting Wild Hawk-owls
Jan 8, 2024 · During. 1975 and 1976 I recorded 11 caching incidents by nesting Hawk-Owl (Surnia ulula) near Fairbanks, Alaska. Previously, Smith (1922) once ...
[40]
[PDF] Reproductive Biology of Northern Hawk-owls in Denali National ...
Two Northern Hawk-Owl pairs were studied in 1980 in Denali National Park, Alaska, including incubation, food habits, and breeding biology. Nests were in open ...
[41]
Northern Hawk Owl - Trends Map - eBird Status and Trends
This map depicts the cumulative change in estimated relative abundance from 2011 through 2021 with circles representing 27km x 27km regions.Missing: climate | Show results with:climate
[42]
Northern hawk-owl (Surnia ulula) longevity, ageing, and life history
A curated database of genes associated with dietary restriction in model organisms either from genetic manipulation experiments or gene expression profiling.Missing: subspecies | Show results with:subspecies
[43]
https://www.sierraclub.bc.ca/ecomap/northern-hawk-owl/
[44]
https://www.adfg.alaska.gov/index.cfm?adfg=wildlifenews.view_article&articles_id=1027
[45]
Boreal Owls in Alaska: Takvialnguaraq
The Inuit have a story about owls; it goes like this: An owl was seeking his dinner when he happened upon a napping lemming. Delighted by his luck, he ...
[46]
[PDF] Owls of Idaho
To the Inuit, the owl is a source of guidance and help. In Hebrew lore, the owl represents blindness and desolation and is unclean. Owl pictures and figurines ...
[47]
The Hidden Lives of Owls - The Marginalian
Mar 13, 2018 · The Scandinavian Sami people believe that owls are good luck. And the Native American Navajo believe owl and coyote hold the balance of day and ...
[48]
Animal Stereotypes and Symbolism in Macbeth - Broncho Blogs - UCO
Oct 7, 2021 · During the persecution of practicers of witchcraft, and in medieval Europe ... During the Middle Ages, owls were seen as evil helpers of witches.
[49]
slavic mythology as a part of our life - Academia.edu
SLAVA - the messenger bird of Perun, often a flame-colored owl. Slava points its wing toward the direction where an army should go. RUSALKA, the spirit of a ...
[50]
Northern Hawk Owl Paintings for Sale - Fine Art America
4.9 2.4K · 1–2 day deliveryChoose your favorite northern hawk owl paintings from 20 available designs. All northern hawk owl paintings ship within 48 hours and include a 30-day ...Missing: wildlife depictions
[51]
BBC Two - Natural World, 2015-2016, Super-Powered Owls
Mar 3, 2015 · Super-Powered Owls ... Wildlife documentary. Owls are one of our best-loved birds, yet it's rare to even catch a glimpse of one in the wild.<|separator|>
[52]
Birdwatchers flock to Okotoks after rare owl sighting - Western Wheel
Feb 5, 2025 · Northern hawk owls are not typically seen in the suburbs, with an expert considering this sighting part of an ongoing 'invasion' of owls across Alberta.