© Copyright: Images: Jari Peltomäki, Jouko Lehmuskallio, Kari Pihlaviita, M. & W. von Wright (Kansalliskirjasto, The National Library of Finland). Recording: Jan-Erik Bruun. All rights reserved.
- Family: Crows – Corvidae
- Appearance: Plumage totally black. Mature birds have white colouring around the featherless base of the beak.
- Size: Length 41–49 cm, wingspan 81–94 cm, weight 370–545 g.
- Nest: In a tree. Smaller than nest of Hooded Crow, made of twigs, lined with dry grass, roots, smaller twigs and bark scales, hair etc.
- Breeding: 3–6 eggs laid in April–May, incubated by female for 16–20 days. Fledglings remain in nest for 28–35 days.
- Distribution: Nests in “rookery” colonies in trees in areas with plenty of farmland, often near human settlements. Most numerous near the towns of Pori and Vaasa. First recorded breeding in Finland in Köyliö in the 1880s. Finnish breeding population estimated at ca. 1.500 pairs.
- Migration: Migrates by day, leaving Finland September–October to spend the winter in Western Europe and Southern Scandinavia. Returns March– May. May occasionally overwinter in Finland.
- Diet: Seeds, grain, berries, invertebrates.
- Calls: A loud “graab”, somewhat hoarser than call of Hooded Crow.
Rooks are similar in size to the related Hooded Crow, but their plumage is uniformly black with a violet metallic sheen. Their beaks are slightly down-turned, and their foreheads rise up steeply to a peak on their crowns, giving their heads a distinctive shape. Mature Rooks have a white featherless patch around the base of the beak, but juvenile birds have dark feathers around their beaks.
Young Rooks can be confused with Carrion Crows (the nominal race of the Hooded Crow, found in Central Europe), but distinguishing features include the shape of their heads and their harsher calls. Rooks have black legs, greyish black beaks and dark brown irises.