© Copyright: Images: Jari Peltomäki, Jouko Lehmuskallio, M., W. & F. von Wright: Svenska fåglar (Kansalliskirjasto, The National Library of Finland), Pohjolan linnut värikuvin. Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Boreal Owl
- Family: Owls – Strigidae
- Appearance: A smallish owl, but considerably larger than Pygmy Owl, with a “startled” appearance. Head large and flattened on top. Back and wings brown with white spots and some less distinct paler streaks on back. Underparts pale with brown markings.
- Size: Length 22–27 cm, wingspan 50–62 cm, weight 105–150 g.
- Nest: In a hole in a tree trunk or a suitable nest box.
- Breeding: 3–9 eggs laid in March–April, incubated by female for 26–27 days. Owlets learn to fly within 30–36 days.
- Distribution: Breeds in coniferous forests from the Åland Islands to Finnish Lapland. Finnish breeding population estimated at 2,000–8,000 pairs (depending on mole stands). Nocturnal.
- Migration: Sedentary, though may range away from own territory in some years, typically in October and March–April. Autumn invasions are east-west in direction, and vary in intensity, but may cover an area extending from Southern Russia to Norway.
- Diet: Small mammals, birds.
- Calls: Courtship territorial call a series of deep whistles lasting several seconds.
- Endangerment: Near threatened, protected.
Tengmalm’s Owls are comparable in size to Fieldfares. They have large flat-topped heads, and their black-edged white face-masks and bright yellow eyes with black raised eyebrows combine to give them a startled expression. Their backs and wings are brown with white spots and some less distinct paler streaks. Their underparts are paler with brown markings. When they leave their nest, owlets’ plumage is almost totally dark brown, and they look very different from their parents. Tengmalm’s Owls’ legs are covered with feathers and have black claws. Their beaks are yellow.
In Finland Tengmalm’s Owl’s worst enemies are Ural Owl and Goshawk and the greatest threat is caused by old coniferous forests’ disappearing (which is caused by human activities in forest industry). It has been estimated that Tengmalm’s Owl’s stand in Finland is disappearing by an average of 2% yearly.