Blakiston’s fish owl is the world’s largest and heaviest owl, with a wingspan of up to 2.0 meters (6.6 feet) and weighing as much as 4.6 kilograms (10.1 pounds). The Eurasian eagle-owl comes close, slightly smaller on average but occasionally rivaling it in both size and mass. The great grey owl holds the record for body length, reaching up to 84 centimeters (33.1 inches), while the snowy owl stands out as the largest owl across the Arctic and North America.
This article explores the largest owls alive today, based on verified maximum measurements from wild individuals. While some captive birds may grow larger, we focus on the most reliable field data for wingspan, weight, and body length. Each entry also highlights key physical adaptations, behavior, range, and conservation concerns, offering a closer look at the planet’s most powerful nocturnal raptors.
Blakiston’s fish owl (Ketupa blakistoni)
- Wingspan: As wide as 2.0 m (6.6 ft).
- Weight: As heavy as 4.6 kg (10.1 lb).
- Body length: Up to 72 cm (28.3 in).
- Where found: Eastern Russia, northeastern China, and Hokkaido, Japan – in old-growth riparian forests.
- Conservation status: Endangered.
Blakiston’s fish owl is the largest living owl by wingspan and overall body weight. Adult females, which are larger than males, can weigh up to 4.6 kilograms (10.1 pounds) and reach a wingspan of 2.0 meters (6.6 feet). Measuring up to 72 centimeters (28.3 inches) in length, this massive owl has broad wings, prominent ear tufts, and dense, shaggy plumage suited to cold climates.
Its large facial disc and piercing yellow eyes contribute to its formidable appearance. Specialized for aquatic hunting, it possesses strong talons and silent flight adaptations that allow it to catch fish along icy rivers and shallow streams.
The species inhabits mature riverine forests with large, hollow trees for nesting and relies on unfrozen, fish-rich waterways year-round. It is found in the Russian Far East, including the southern Kurils, eastern China, and central to eastern Hokkaido in Japan. Once present on Sakhalin Island, it is now likely extinct there. The global population is estimated at 1,000-1,700 mature individuals and is fragmented into mainland and island subspecies.
While numbers have shown slight increases in Japan thanks to conservation measures such as nest boxes and supplementary feeding, habitat loss from logging, river development, and declining fish stocks continues to threaten mainland populations. Blakiston’s fish owl remains one of the rarest and most habitat-dependent owl species in the world, relying on a delicate balance of old-growth forests, undisturbed river systems, and stable fish populations to survive and reproduce.
Eurasian eagle owl (Bubo bubo)
- Wingspan: As wide as 2.0 m (6.6 ft).
- Weight: As heavy as 4.6 kg (10.1 lb).
- Body length: Up to 75 cm (29.5 in).
- Where found: Across Eurasia – from Iberia and Scandinavia to China, inhabiting rocky terrain, forests, and taiga.
- Conservation status: Least Concern.
The Eurasian eagle-owl is considered the second-largest living owl, with females reaching up to 4.6 kilograms (10.1 pounds) in weight and wingspans of up to 2.0 meters (6.6 feet). Though similar in size to the Blakiston’s fish owl at the upper extremes, it averages slightly smaller in both mass and wingspan across individuals, though it can occasionally exceed the Blakiston’s in body length.
This imposing species is characterized by its orange eyes, prominent ear tufts, mottled brown plumage, and a deep, booming hoot. Its size, strength, and versatility have earned it a place as one of the most formidable nocturnal predators in the Northern Hemisphere.
It inhabits an exceptionally broad range across Europe and Asia, from the Iberian Peninsula and Scandinavia to the Russian Far East, China, and parts of the Middle East and South Asia. The species favors rocky landscapes, cliffs, forest edges, and wooded valleys, often nesting on ledges, in caves, or occasionally in old tree nests. It preys on a wide variety of animals, including rodents, rabbits, birds, reptiles, and even other owls.
Despite its overall stable global population, localized declines have occurred due to habitat disturbance, recreational activities near nests, persecution, and accidental poisoning. Under favorable conditions, the Eurasian eagle owl is also one of the longest-lived bird species, capable of surviving several decades in captivity or protected environments.
Great grey owl (Strix nebulosa)
- Wingspan: As wide as 1.53 m (5.0 ft).
- Weight: As heavy as 1.9 kg (4.2 lb).
- Body length: Up to 84 cm (33.1 in).
- Where found: Boreal forests across North America and Eurasia – favoring dense coniferous woodlands near meadows or bogs.
- Conservation status: Least Concern.
The great grey owl is the longest owl in the world by body length, reaching up to 84 centimeters (33.1 inches). However, much of its imposing size is an illusion, created by its dense plumage, exceptionally large facial disc, and the longest tail of any living owl – features that exaggerate its height while concealing a body lighter than that of many similarly sized species.
In fact, despite its impressive profile, it weighs up to only 1.9 kilograms (4.2 pounds) and has a wingspan of up to 1.53 meters (5 feet), making it large in stature but not the most massive among its peers.
This owl inhabits the taiga and boreal forest zones across Canada, Alaska, northern Europe, and Siberia, extending southward into montane forests of the western United States. It prefers mature coniferous forests interspersed with open meadows, bogs, or clearcuts where small mammals such as voles are abundant. While most populations are sedentary, some individuals migrate short distances in winter, particularly in years of prey scarcity.
Although globally stable, local threats include logging, vehicle collisions, disturbance from human recreation, and exposure to poisons. Climate change is shifting its range northward, and it is known to be vulnerable to West Nile virus. Despite these pressures, the great grey owl remains widespread and one of the most iconic large raptors of the northern forests.
Snowy owl (Bubo scandiacus)
- Wingspan: As wide as 1.83 m (6.0 ft).
- Weight: As heavy as 2.95 kg (6.5 lb).
- Body length: Up to 71 cm (28.0 in).
- Where found: Arctic tundra across North America, Europe, and Russia; winters further south in open fields and coastal areas.
- Conservation status: Vulnerable.
The snowy owl is the largest owl found in North America by wingspan and weight, with females reaching up to 2.95 kilograms (6.5 pounds) and wingspans as wide as 1.83 meters (6 feet). Though slightly shorter in length than the great grey owl, it surpasses it in mass and wingspan, making it the dominant avian predator of the High Arctic.
The thick white plumage, heavily barred in females and immatures, provides excellent insulation and camouflage against snow. Unlike many large owls, the snowy owl is not strictly nocturnal. It is cathemeral, with activity patterns shifting between day and night depending on season, prey movements, and light availability. In the Arctic summer, peak hunting often occurs during the darkest twilight hours, while in winter, activity can be seen both at dawn and dusk.
This species breeds on open Arctic tundra from Scandinavia to Siberia, Alaska, and northern Canada, nesting on elevated ground with low vegetation. It primarily feeds on lemmings and voles but can take a wide range of prey including hares, ptarmigans, ducks, and even medium-sized geese when available.
Snowy owls are highly nomadic and irruptive, with southern movements in winter closely tied to prey abundance in the north. While some remain year-round in Arctic regions, others migrate unpredictably, even reaching temperate zones. Climate change, prey fluctuations, infrastructure collisions, poisoning, and past persecution all contribute to ongoing population declines, making the snowy owl increasingly vulnerable despite its vast range.
Verreaux’s eagle owl (Ketupa lactea)
- Wingspan: As wide as 1.64 m (5.4 ft).
- Weight: As heavy as 3.15 kg (6.9 lb).
- Body length: Up to 66 cm (26.0 in).
- Where found: Sub-Saharan Africa – mainly in dry savannas, thorn scrub, and open woodlands.
- Conservation status: Least Concern.
Verreaux’s eagle owl is the largest owl in Africa and one of the most powerfully built in the world, with females reaching up to 3.15 kilograms (6.9 pounds) in weight and wingspans of 1.64 meters (5.4 feet). It is also among the most sexually dimorphic of all living owl species, with females averaging up to 35% heavier than males in some populations.
With its pale eyelids, massive greyish body, and deep, rasping vocalizations, this owl is unmistakable in its native range. Despite not being the longest owl, its robust frame and strong talons make it a formidable nocturnal predator across Africa’s open landscapes.
Widespread across sub-Saharan Africa, Verreaux’s eagle owl occupies dry savanna, thorn scrub, riverine woodland, and bushveld, often avoiding dense forests and high mountains. It roosts by day in shaded tall trees and becomes active at night, patrolling vast territories that can span up to 7,000 hectares. While usually solitary or paired, some family groups may roost together for extended periods, even including offspring from previous years – an uncommon behavior among owls.
The species has adapted to changes in land use in some areas, but overall numbers may be slowly declining due to habitat alteration and local pressures. Nonetheless, it remains relatively widespread and secure across much of its range.
Great horned owl (Bubo virginianus)
- Wingspan: As wide as 1.53 m (5.0 ft).
- Weight: As heavy as 2.5 kg (5.5 lb).
- Body length: Up to 64 cm (25.2 in).
- Where found: From subarctic Canada to South America – in forests, deserts, grasslands, and fragmented habitats.
- Conservation status: Least Concern.
The great horned owl is the second-heaviest owl in North America and the heaviest in Central and South America. Females of northern populations can weigh up to 2.5 kilograms (5.5 pounds), with wingspans reaching 1.53 meters (5 feet). Though body length tops out around 64 centimeters (25.2 inches), this species shows considerable regional variation in size, with individuals from Alaska and Ontario being notably larger than their counterparts in California, Texas, or the Yucatan Peninsula.
Its piercing yellow eyes, prominent feather tufts, and deep hooting call make it one of the most recognizable owls of the Americas. Equipped with crushing talons and exceptional adaptability, it ranks among the most formidable avian predators in the Western Hemisphere.
This owl occupies an enormous range across two continents, from subarctic Canada to upland Peru and Argentina. It thrives in a wide array of environments, including woodlands, deserts, wetlands, grasslands, mountain slopes, and even urban parks, especially where open hunting grounds are near sheltered roosting or nesting areas. It is primarily nocturnal but may hunt in daylight during harsh winters or food shortages.
Mated pairs are strongly territorial and defend nesting areas vigorously, sometimes attacking large intruders, including humans, with silent, swift strikes. While not typically considered among the most dangerous species to humans, such encounters are rare but well-documented, and injuries do occur, especially during the breeding season. Thanks to its versatility and strength, the great horned owl remains a stable and successful predator throughout most of its range.
Powerful owl (Ninox strenua)
- Wingspan: As wide as 1.4 m (4.6 ft).
- Weight: As heavy as 1.6 kg (3.5 lb).
- Body length: Up to 65 cm (25.6 in).
- Where found: Eastern Australia – in sclerophyll forests, wooded gullies, and suburban parks.
- Conservation status: Least Concern.
The powerful owl is the largest owl in Australia and the top nocturnal predator in many of the country’s eastern forests. Measuring up to 65 centimeters (25.6 inches) in body length and weighing as much as 1.6 kilograms (3.5 pounds), it has a wingspan that can reach 1.4 meters (4.6 feet).
Despite its upright, streamlined appearance, this species is a specialist in ambush hunting, preying heavily on arboreal mammals like possums and flying foxes. It has striking yellow eyes, broad rounded wings, and heavily feathered legs with sharp talons – all adaptations for silent, powerful strikes from cover.
This owl ranges from Queensland to South Australia, favoring tall eucalypt forests, damp gullies, and mixed woodland along ridgelines and streams. It also adapts surprisingly well to human-modified landscapes, now occurring in urban fringes and parks in major cities like Sydney, Melbourne, and Brisbane.
While deforestation and logging have reduced nesting sites in parts of its range, the species persists in mosaics of logged and unlogged forest, and often nests in old tree hollows while foraging more broadly. Its population is considered stable overall, though local threats include habitat loss, fox predation, and nest disturbance.
Largest owls that ever lived
While the owls featured above represent the largest species alive today, they are not the largest owls to have ever existed. That distinction likely belongs to the giant Cuban owl (Ornimegalonyx), an extinct species that lived during the Pleistocene epoch. Flightless or nearly flightless, Ornimegalonyx is estimated to have stood up to 1.1 meters (3.6 feet) tall and weighed as much as 13.5 kilograms (29.8 pounds), with some studies suggesting it could have been even heavier. Though its wingspan remains uncertain, reconstructions propose a possible spread exceeding 3 meters (9.8 feet).
Despite its enormous size, the Cuban giant owl may have shared certain behavioral traits with one of the smallest living owls – the burrowing owl (Athene cunicularia). Like its modern relative, Ornimegalonyx was strongly adapted to life on the ground, likely preying on small mammals and reptiles in the forests and grasslands of ancient Cuba. Its fossil record offers a striking glimpse into how diverse, and how massive, owls could once be.
Further reading