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What the sources say

Snowy OwlBubo scandiacus

Every figure, record and mechanism on the Snowy Owl profile was written from a source, and this is the working table behind it: 53 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Animal Diversity Web, University of Michigan

Nyctea scandiaca (snowy owl). Animal Diversity Web, University of Michigan.

The page saysaround the northern parts of North America and Eurasia
The source saysSnowy owls have a circumpolar distribution. They breed in coastal Alaska, Canada, and Greenland, as well as in northern Scandinavia, Russia, southern Novaya Zemlya and northern Siberia.
The page saysMost owls rule the night, but Animal Diversity Web calls the snowy owl "largely diurnal,"
The source saysUnlike most owls, snowy owls are largely diurnal.
The page saysits breeding range runs from coastal Alaska, Canada and Greenland to northern Scandinavia, Russia and northern Siberia
The source saysThey breed in coastal Alaska, Canada, and Greenland, as well as in northern Scandinavia, Russia, southern Novaya Zemlya and northern Siberia.
The page saysThick white feathers cover its legs and feet, protecting them from the cold
The source saystheir legs and feet are covered in white feathers that protect them from the cold weather
The page saysAnimal Diversity Web says it can swivel its head three-quarters of the way around, 270 degrees, to scan its hunting ground
The source saysVisual scanning of the hunting area is facilitated by their ability to swivel their head three quarters of the way around (270 degrees).Note: attributed to ADW because its account is old; San Diego Zoo's owl page agrees at family scope: 'most owls turn their head no more than 270 degrees in either direction'
The page saysThe female picks a low, windswept rise such as a hummock or boulder, then scrapes out a shallow bowl in the turf or bare ground and leaves it unlined
The source saysthe female selects a nest site, which is a low windswept prominence, such as a hillock, hummock or boulder. The female constructs a nest by scraping out a shallow bowl in the turf or bare ground. The nest is not lined with any insulating materials.
The page saysSnowy owls are also wanderers, moving nomadically and breeding where prey is abundant
The source saysIn general, snowy owls move nomadically, and breed when and where prey is abundant.
The page saysdangerLevel: Medium
The source saysBoth sexes attack approaching predators, dive-bombing them and engage in distraction displays to draw the predator away from the nest.Note: #913: kept; ADW lists humans first among its known predators, and no source reports a serious injury to a person

Source
02

Audubon Guide to North American Birds

Snowy Owl. Audubon Guide to North American Birds.

The page saysA powerful owl of the Arctic tundra
The source saysA large, powerful owl of the high Arctic tundra
The page saysoften hunts by day
The source saysOften hunts by day.
The page sayscolored for winter camouflage
The source sayscolored for camouflage during northern winters
The page saysable to take birds as big as geese
The source saysAt other times it takes a wide variety of prey, including birds as big as geese.
The page saysalso rabbits and hares, and on coasts it may feed heavily on ducks and geese
The source saysTakes mammals including rabbits, hares, voles, ground squirrels. In coastal areas may feed heavily on birds, including ducks, geese, grebes, murrelets, and sometimes songbirds.
The page saysUsually watches for prey from a perch
The source saysUsually hunts by watching for prey from a perch, then pursuing it in swift flight and catching prey in talons.
The page saysAudubon notes that it often hunts by day
The source saysOften hunts by day.
The page saysAudubon gives an adult's length as about 61 centimeters (24 inches), with wings spanning 1.4 meters (4 feet 7 inches)
The source says24" (61 cm). W. 4' 7 (1.4 m).Note: 61 cm = 24 in; 1.4 m = 4 ft 7 in, as the source prints both
The page saysA snowy owl usually hunts by watching for prey from a perch
The source saysUsually hunts by watching for prey from a perch, then pursuing it in swift flight and catching prey in talons.
The page saysbut it also takes rabbits and hares, and along coasts it may feed heavily on ducks and geese
The source saysTakes mammals including rabbits, hares, voles, ground squirrels. In coastal areas may feed heavily on birds, including ducks, geese, grebes, murrelets, and sometimes songbirds.
The page saysDuring some winters, large numbers appear south of the Canadian border
The source saysDuring some winters, large numbers of Snowy Owls appear south of the Canadian border
The page saysIn the Arctic it may eat almost nothing but lemmings when they are around
The source saysIn Arctic, may feed almost exclusively on lemmings when these are available.Note: 'almost nothing but' paraphrases 'almost exclusively'
The page saysin many Arctic regions it may breed mainly in years when lemmings are plentiful, skipping nesting altogether when they are scarce
The source saysIn many regions of Arctic, may breed mainly in years when lemmings are abundant, failing to nest at all when lemmings are scarce.
The page saysanywhere from 3 to 11 eggs, with more laid when prey is abundant
The source saysEggs 3-11. Clutch size quite variable, with more eggs laid in years when prey is abundant.
The page saysAudubon's guide sums up the extremes: young females are heavily marked, while old males are almost pure white
The source saysyoung females heavily marked, old males almost pure white
The page saysYoung snowy owls may leave the nest after two to three weeks, but Audubon says they cannot fly well until about seven weeks old
The source saysYoung may leave nest after 2-3 weeks, but not able to fly well until about 7 weeks
The page saysOften heavily.
The source saysIn Arctic, may feed almost exclusively on lemmings when these are available.
The page saysan owl that often hunts by day
The source saysOften hunts by day.Note: vibe.reason, re-paired in #913

Source
03

Owl Research Institute

Snowy Owl. Owl Research Institute.

The page saysArctic tundra when nesting; meadows, marshes and dunes at other times
The source saysTundra, meadows, marshes, dunes; during nesting season, lives on the tundra
The page saysMostly lemmings, voles and other rodents
The source saysMostly lemmings, voles, and other rodents
The page saysswoops down in a "wallop" to snatch it with strong talons
The source saysUse a 'wallop' hunting method - swooping down and snatching prey with their strong talons
The page saysIt nests on the tundra
The source saysduring nesting season, lives on the tundra
The page saysIn winter it often moves south to southern Canada, the northern United States and similar latitudes around the world
The source saysCircumpolar; summer in Arctic, often spend winter in southern Canada, northern U.S., and similar latitudes around the world
The page sayswhere it turns up on meadows, marshes and dunes
The source saysTundra, meadows, marshes, dunes; during nesting season, lives on the tundra
The page saysfemales outsize males
The source saysFemales outsize males. Height: Males 55-64 cm (21-23 in), Females 60-75 cm (22-26 in)
The page saysThick white feathers
The source sayswhite owl with bright yellow eyes, a dark beak, and thickly feathered feet
The page saysAdult males are pure white, while females are white with dark bars or spots
The source saysMales: adult males are pure white Females: white with dark bars or spots
The page saysThen it launches what the Owl Research Institute calls a "wallop", swooping down to snatch the target in its strong talons
The source saysUse a 'wallop' hunting method - swooping down and snatching prey with their strong talons
The page saysIts diet is mostly lemmings, voles and other rodents
The source saysMostly lemmings, voles, and other rodents
The page saysIt is one of the few owls that builds its own nest
The source saysOne of the few species of owl that builds its own nest
The page saysMostly by day. The Owl Research Institute calls it mostly diurnal
The source saysMostly diurnal, but will hunt any time of day in the constant daylight of Arctic summer
The page saysin the constant daylight of the Arctic summer it will hunt at any time of day
The source saysMostly diurnal, but will hunt any time of day in the constant daylight of Arctic summer
The page saysA young snowy owl resembles an adult female
The source saysFemales: white with dark bars or spots Young: resemble females
The page saysmales take several years to turn totally white
The source saysIt takes several years for males to turn totally white
The page saysAdult females still show dark bars or spots
The source saysFemales: white with dark bars or spots
The page saysAge and sex both play a part.
The source saysIt takes several years for males to turn totally white
The page saysChicks toddle before they fly.
The source saysFledglings leave the nest and spend nearly a month hiding & toddling around the tundra before they are able to fly
The page saysThe Owl Research Institute describes fledglings spending nearly a month hiding and toddling around the tundra first
The source saysFledglings leave the nest and spend nearly a month hiding & toddling around the tundra before they are able to fly
The page saysit usually watches for prey from a perch, then swoops down in a "wallop" to snatch it with strong talons
The source saysUse a 'wallop' hunting method - swooping down and snatching prey with their strong talonsNote: vibe.reason, re-paired in #913; the perch half is Audubon's 'Usually hunts by watching for prey from a perch', claimed on the superpower line

Source
04

AnAge: The Animal Ageing and Longevity Database, Human Ageing Genomic Resources

Bubo scandiacus. AnAge: The Animal Ageing and Longevity Database, Human Ageing Genomic Resources.

The page saysAdults weigh around 2 kilograms (4.5 pounds) on average
The source saysAdult weight 2,043 gNote: 2,043 g rounded to 2 kg / 4.5 lb
The page saysAnAge records one captive bird that lived at least 28 years
The source saysOne captive specimen lived at least 28 years

Source
05

Robillard et al. 2016

Robillard et al. (2016). Pulsed resources at tundra breeding sites affect winter irruptions at temperate latitudes of a top predator, the snowy owl. Oecologia.

The page saysIn temperate North America these winter irruptions come every three to five years
The source saysperiodic winter irruptions of snowy owls Bubo scandiacus every 3-5 years in temperate North America
The page saysa 2016 study found that winter owl numbers rose and fell with small-mammal numbers at two Canadian tundra sites the summer before
The source sayssummer abundance of small mammals was collected in summer at two distant sites in Canada: Bylot Island, NU (eastern High Arctic) and Daring Lake, NWT (central Low Arctic). Winter owl abundance was positively related to prey abundance during the previous summer at both sitesNote: 2016 is the paper's publication year (reference pulsed-2016); 'rose and fell with' paraphrases 'positively related to', a correlation
The page saysThat fits the idea that a good summer lets the owls raise more young, swelling the number of migrants heading south the following winter
The source sayshigh abundance of tundra small mammals during the summer allows for high production of young, thus increasing the pool of migrants moving south the following winter. ... Irruptive migration of snowy owls was therefore best explained by the breeding success hypothesisNote: 'lets' paraphrases 'allows for'; framed as the hypothesis the study found best explained the data, not as a measured count of young

Source
06

The IUCN Red List of Threatened Species 2021

Bubo scandiacus. The IUCN Red List of Threatened Species 2021: e.T22689055A205475036.

The page saysVulnerable
The source saysIUCN category (GBIF's copy of the Red List): VulnerableNote: status verifies through GBIF's copy of the assessment, checked against the taxon id inside the DOI, per docs/fact-check.md

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.