# Snowy Owl — Facts, Threats & Conservation

*Bubo scandiacus (Linnaeus, 1758) — family Strigidae*

> The snowy owl (Bubo scandiacus) is a large, mainly white Arctic owl that hunts by day and is nomadic rather than territorial; its breeding success tracks lemming abundance, and it was reclassified as Vulnerable in 2017.

**IUCN status:** Vulnerable — reassessed in 2017 after population estimates were revised sharply downward  ·  **WARN range:** Arctic tundra of North America, Greenland, Scandinavia and Russia, Irregular winter movements far south of the breeding range

## Quick facts
| Fact | Value |
| --- | --- |
| Weight | 1.6–2.9 kg — heaviest North American owl |
| Wingspan | 125–150 cm |
| Activity | Diurnal — hunts in daylight |
| Main prey | Lemmings; also voles, ptarmigan and waterfowl |
| Movement | Nomadic, not territorial |
| Key threat | Climate disruption of the lemming cycle |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Aves
- **Order:** Strigiformes
- **Family:** Strigidae
- **Genus:** Bubo
- **Species:** Bubo scandiacus

## Conservation status
- **Status:** Vulnerable
- **Population:** Revised sharply downward after tracking studies; estimates remain uncertain
- **Trend:** Decreasing
- **Assessed:** 2017 (reclassified from Least Concern)
- **CITES:** Appendix II (all Strigiformes)
- The 2017 reclassification followed improved measurement rather than a new threat: tracking showed individuals range so widely that earlier surveys counted the same birds more than once.

## Key facts: Snowy Owl
- Snowy owls hunt in daylight — an adaptation to the Arctic summer's continuous light.
- Breeding is tied to lemming abundance; in poor years pairs may not breed at all.
- They are nomadic, not territorial, moving across the Arctic between seasons.
- Males whiten with age; females and juveniles retain dark barring.
- 'Irruptions' bring birds far south in some winters — usually young birds after a good breeding year.
- Reclassified from Least Concern to Vulnerable in 2017 when population estimates were revised down.

## Life on the lemming cycle
Arctic lemming populations rise and crash on multi-year cycles, and snowy owl reproduction follows them closely. In a peak lemming year a female may lay a large clutch and fledge many young; in a crash year the pair may skip breeding entirely rather than start a nest that cannot be provisioned.

This makes snowy owl numbers naturally volatile and makes any single-season count misleading. It also means the birds cannot afford to sit still: they move to wherever rodents are abundant, sometimes thousands of kilometres between consecutive breeding attempts.

## Why the status changed in 2017
Snowy owls were long listed as Least Concern on the assumption of a large global population. Satellite tracking then revealed that individual birds range enormously and that the same owls were being counted in different places, meaning earlier estimates had substantially overcounted.

The revised figure was far lower, and combined with evidence of decline the IUCN moved the species to Vulnerable in 2017. It is a good example of a status change driven by better measurement rather than by a sudden new threat.

## Irruptions
In some winters snowy owls appear well south of their range — across southern Canada, the northern United States, and occasionally western Europe. These irruptions are widely reported as birds fleeing starvation, but the pattern often follows a *good* breeding season: an unusually large cohort of young birds disperses widely.

Irrupting owls are typically juveniles, often in poor condition by the time they are noticed, and they attract crowds. Repeated disturbance at a roost forces a bird already low on reserves to burn more energy, which is why photographers and birders are asked to keep distance and never bait owls with live or dead prey to obtain a flight shot.

## Pressures on an Arctic specialist
Climate change is the central long-term threat: warming disrupts the snow conditions lemmings depend on for winter breeding beneath the snowpack, which destabilises the cycle the owls rely on. Rain-on-snow events and shifting vegetation compound it.

Other documented pressures include collisions with vehicles and aircraft when birds winter in open agricultural and airport landscapes that resemble tundra, secondary rodenticide poisoning in wintering areas, and localised hunting. Disturbance at wintering sites is an increasing, and entirely avoidable, addition.

## What WARN does
WARN publishes free, sourced species education including the cases where public behaviour matters directly. Wintering snowy owls are among the most photographed wild birds in the world, and the difference between a bird surviving the winter and not can come down to how often it is flushed from a roost.

If this guide helps you understand wildlife and the pressures it faces, a gift to WARN supports habitat protection and free public education in our partner countries.

## Frequently asked questions: Snowy Owl
### Are snowy owls endangered?
They are listed as Vulnerable. The IUCN moved the snowy owl from Least Concern in 2017 after satellite tracking showed individual birds range so widely that earlier surveys had double-counted them, meaning the true population is far smaller than assumed.

### Do snowy owls hunt during the day?
Yes. Unlike most owls they hunt in daylight, an adaptation to an Arctic summer with continuous light and no night to hunt in. They remain active in daylight in their wintering areas too.

### Why do snowy owls appear far south some winters?
These movements are called irruptions. They often follow a good breeding season rather than a bad one: a large cohort of young owls disperses widely in search of unoccupied hunting ground. Most irrupting birds are juveniles.

### Do snowy owls turn whiter as they age?
Males do, becoming progressively whiter over successive moults, with the oldest appearing almost pure white. Females and juveniles keep dark barring across the white plumage throughout their lives.

### What do snowy owls eat?
Mainly lemmings — an adult may take around 1,600 in a year — supplemented by voles, ptarmigan, waterfowl, hares and, in coastal areas, seabirds. Their whole breeding cycle is tied to lemming abundance.

### Where do snowy owls live?
Snowy Owls live in Arctic tundra of North America, Greenland, Scandinavia and Russia, Irregular winter movements far south of the breeding range. The snowy owl (Bubo scandiacus) is a large, mainly white Arctic owl that hunts by day and is nomadic rather than territorial; its breeding success tracks lemming abundance, and it was reclassified as Vulnerable in 2017.

### Are snowy owls dangerous?
Snowy Owls are not generally dangerous to people. The snowy owl (Bubo scandiacus) is a large, mainly white Arctic owl that hunts by day and is nomadic rather than territorial; its breeding success tracks lemming abundance, and it was reclassified as Vulnerable in 2017. Give wild individuals space and do not corner or handle them.

### How long do snowy owls live?
A precise wild lifespan for snowy owls is not firmly established in the sources cited on this guide. The snowy owl (Bubo scandiacus) is a large, mainly white Arctic owl that hunts by day and is nomadic rather than territorial; its breeding success tracks lemming abundance, and it was reclassified as Vulnerable in 2017. Where longevity figures appear in the literature they vary by region, sex and whether animals are wild or captive.

### How big is a snowy owl?
A Snowy Owl is about 1.6–2.9 kg — heaviest North American owl. The snowy owl (Bubo scandiacus) is a large, mainly white Arctic owl that hunts by day and is nomadic rather than territorial; its breeding success tracks lemming abundance, and it was reclassified as Vulnerable in 2017. Conservation status: Climate disruption of the lemming cycle.

## Sources
- [IUCN Red List — Bubo scandiacus](https://www.iucnredlist.org/species/22689055/155542936)
- [CITES Appendices](https://cites.org/eng/app/appendices.php)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/snowy-owl