The Northern Hawk-Owl (Surnia ulula) is a day-active owl with a hawk-like build, a long tail and a pale face bordered by a dark rim, often seen sitting openly atop a tree scanning for prey — a habit that sets it apart from most other owls. It measures 35–40 cm, has a wingspan of about 74–81 cm and weighs 250–380 grams. It is dark brown above with pale spots and shows a pale, densely barred underside, but its most distinctive features are the long tail, which gives it a slender, hawk-like silhouette, and the pale face framed by a bold, almost black border around yellow eyes.
Its song is a long, rolling, bubbling trill, often rendered as a rapid "ki-ki-ki-ki" or a buzzing "ulululul", audible both day and night during the breeding season, while alarmed birds give hard, sharp warning calls — the scientific name ulula even alludes to these wailing sounds. The Northern Hawk-Owl breeds in the coniferous forests of northern Sweden, with a population in the thousands of pairs that fluctuates sharply from year to year depending on the abundance of small rodents; in years of scarcity in the north it can irrupt southward, sometimes reaching as far as Götaland. It nests in cavities — a natural tree hollow, the top of a broken, rotten stump, or a nest box — and the female lays a clutch of usually 5–9 eggs, with clutch size directly tracking vole abundance: good rodent years bring large broods and high productivity, while poor years can mean breeding fails altogether. The owl hunts mainly small rodents, especially voles, supplemented with small birds, often watching from a treetop perch or hovering over open ground, and defends its nest vigorously against intruders.
Read about this species in Swedish →