Northern Hawk-owl (Surnia ulula)

Here’s a full natural history overview of the Northern Hawk-Owl (Surnia ulula), one of the most unusual owls in the Northern Hemisphere:


Northern Hawk-Owl (Surnia ulula)

Taxonomy & Classification

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Aves
  • Order: Strigiformes
  • Family: Strigidae (Typical owls)
  • Genus: Surnia
  • Species: S. ulula
  • Common names: Northern Hawk-Owl, Hawk Owl

General Description

  • Size: 35–45 cm in length, wingspan about 70–85 cm.
  • Weight: 300–400 g.
  • Appearance:
    • Long-tailed owl with a slim, hawk-like silhouette.
    • Upperparts brown with white spotting; underparts pale with dark streaks.
    • Rounded head without ear tufts.
    • Yellow eyes and hooked beak typical of owls.
  • Distinctive feature: Often mistaken for a hawk due to its long tail, pointed wings, and daytime hunting behavior.

Behavior & Lifestyle

  • Diurnal hunter: Unlike most owls, it is active during the day, especially in the morning and afternoon.
  • Perching style: Sits on tall trees, snags, or poles to scan the ground for prey.
  • Flight: Swift and hawk-like, adapted for pursuing prey in open areas.
  • Vocalizations: A rapid, high-pitched trill or series of whistles, used mainly in the breeding season.
See also  European robin (Erithacus rubecula)

Diet

  • Primary food: Small mammals (voles, lemmings, mice) are the main diet.
  • Birds: Occasionally takes small to medium-sized birds, especially in winter when rodents are scarce.
  • Hunting strategy:
    • Uses keen eyesight to spot prey from perches.
    • Can detect small movements even in low light.
    • Dives rapidly from perch to capture prey with talons.

Life Cycle & Breeding

  • Breeding season: Spring (April–June), depending on latitude and food supply.
  • Nesting sites: Uses natural tree cavities, broken tops of snags, or old woodpecker holes.
  • Clutch size: 3–7 eggs, more in years of abundant rodent populations.
  • Incubation: 25–30 days, mainly by the female.
  • Fledging: Chicks leave the nest about 3–4 weeks after hatching but remain dependent on parents for several weeks.

Habitat

  • Prefers boreal forests interspersed with open areas such as bogs, clearings, meadows, and tundra edges.
  • Often seen in forest openings where prey is easier to spot.
See also  Common Rosefinch (Carpodacus erythrinus)

Geographic Range

  • Found across the northern boreal regions of North America, Europe, and Asia.
  • Distribution stretches from Alaska and Canada through Scandinavia and across Siberia.

Ecological Role

  • Rodent control: Plays an important role in regulating vole and lemming populations.
  • Prey base: Provides food for larger raptors and predators.
  • Indicator species: Population booms and declines are tied to rodent cycles, reflecting the health of northern ecosystems.

Conservation Status

  • IUCN Red List: Least Concern.
  • Population trends: Generally stable, though fluctuations occur with prey availability.
  • Threats:
    • Habitat loss through logging and development.
    • Declines in prey populations due to climate change and human disturbance.
  • Conservation measures: Protecting boreal forests and maintaining dead trees for nesting cavities.

Interesting Facts

  • One of the few truly diurnal owls, alongside species like the snowy owl.
  • Can spot prey up to 800 meters away, thanks to exceptional vision.
  • In peak vole years, pairs may raise unusually large broods.
  • Its hawk-like hunting style gives it its name, though it is a true owl.
See also  Castor bean tick (Ixodes ricinus)

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