Great Grey Owl

• It is the longest owl in the world by body length, despite being very light.
• It can detect rodents hidden under as much as 60 cm of snow by sound alone.
• Its asymmetric hearing lets it pinpoint prey with extreme accuracy.
• sentidosIt has the largest facial disc of any owl known, which markedly improves its ability to hear small rodents beneath the snow.

Skeleton type

Vertebrate - pneumatised bony skeleton (bird)

Habitat & environment

Dense boreal coniferous forest of North America and Eurasia, including the mountains of the western United States

Birth weight

37.5 grams

Size at birth

Semi-altricial, with white down and its eyes open on hatching

Sexual maturity

1 year (though effective breeding is usually delayed to 3-4 years)

Gestation / incubation

28-36 days

Litter / clutch size

2 to 5 eggs per clutch (most commonly 3-4)

Lifespan in captivity

Unconfirmed reports of up to 27-40 years in captivity

Sources consulted: AnAge (genomics.senescence.info); Earth Life; The Owl Pages; Animal Diversity Web; The Animal Facts; Animalia.bio; California DFG life history account; Wikipedia (Great grey owl)

Best time: Winter, when it comes down into clearings and open ground and hunts in broad daylight over the snow; it is especially visible in irruption years, when birds move south.