© Copyright: Images: Jari Peltomäki. Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Eurasian Bittern, Great Bittern
- Family: Herons – Ardeidae
- Appearance: Seldom seen, but more often heard, Bitterns breed and live in extensive reed beds. They are large yellowish brown members of the heron family. Features visible in flight include broad wings, a shortish neck and long, trailing legs extending behind their shorter tails.
- Size: Length 69–81 cm, wingspan 100–130 cm, weight 870–1,940 g.
- Nest: A flattened pile of short fragments of reeds from the previous summer, surprisingly small compared to the Bittern’s large size (smaller than nest of Coot). Built in shallow water, usually among dense reeds.
- Breeding: 5–7 eggs laid May–June, incubated by female for 25–26 days. Fledglings may leave the nest after just 10 days, and learn to fly within 50–55 days.
- Distribution: Breeds in extensive reed beds by nutrient-rich waters in Southern Finland. Has become more numerous in Finland recently. Present population estimated at 1,000–1,500 pairs.
- Migration: Nocturnal. Autumn migration August–October, returning from early March onwards. Winters in Western and Southern Europe and Africa.
- Diet: Fish, frogs and fledglings of other birds.
- Calls: Best known for its territorial call, a loud, foghorn-like booming call, repeated 3–5 times, and audible for long distances (up to 5 km or further).
Bitterns are members of the heron family, with long legs and a dagger-like bill. Their plumage is streaked lengthwise with brown, yellowish and black markings. In flight they initially hold their longish necks out straight, but soon tuck in their necks and trail their legs behind their tails like Grey Herons. Their wings are arched convexly with rounded ends. Their wingbeats are faster than those of the Grey Heron. Bitterns have greenish yellow bills and legs, and their irises are yellow.