The Boreal Owl (Aegolius funereus) is a small, compact owl of the coniferous forest belt, about 22–27 cm long with a wingspan of roughly 50–62 cm and a weight of 100–200 g. The upperparts are greyish-brown with white spots, the underparts white with diffuse brown streaking, and the most distinctive feature is the large, almost square head with a pale facial disc dotted with small white spots on the forehead — the "pearls" that give the species its Swedish name, Pärluggla. The disc is edged with a bold dark border, and the large yellow eyes give the bird a characteristic, slightly startled expression.
The male's song is a fast, gently accelerating, rising series of six to twelve "po" notes, repeated in long phrases on calm, clear nights in March and April, and often the only reliable sign of the species since it hides well by day. Boreal Owls occur across the coniferous forest belt over most of Sweden, Norway and Finland as year-round residents, favouring older spruce forest with large trees; the Swedish population is estimated at roughly 5,000–15,000 pairs, though numbers fluctuate strongly with the abundance of voles and mice, their main prey. The species is a hole-nester, depending chiefly on abandoned Black Woodpecker holes but also readily using large nest boxes; the female lays 4–7 eggs, though clutch size varies considerably with rodent numbers, and the male provisions the family while the female incubates. The species is classified as Least Concern (LC).
Read about this species in Swedish →