Boreal Owl

• It nests almost exclusively in abandoned woodpecker holes.
• Its chicks hatch at intervals, with up to a week between first and last.
• Only 50% of young males survive their first year, against 67% of adults.
• sentidosIts ears sit at slightly different heights on the skull, an asymmetry that sharpens its ability to pinpoint prey by sound in the total darkness of the boreal winter.

Skeleton type

Vertebrate - pneumatised bony skeleton (bird)

Habitat & environment

Boreal coniferous forest of North America and Eurasia, in mountains up to 3,200 m in some regions

Birth weight

9 grams

Size at birth

Altricial at hatching

Sexual maturity

9 months to 1 year

Gestation / incubation

25-32 days

Litter / clutch size

3 to 11 eggs per clutch (most commonly 4-6)

Sources consulted: AnAge (genomics.senescence.info); Birda; Animal Diversity Web; The Owl Pages; World Species; PMC (nestling perching behaviour study, nestling growth study, post-fledging movement study)

Best time: From February to April, at night, in boreal and mountain forests, when the male calls insistently beside the nest.