The Eurasian Treecreeper or Common Treecreeper (Certhia familiaris) is a small, insignificant bird and has a curved bill, patterned brown upperparts, whitish underparts, a broad, white eye-stripe and long stiff tail feathers which help it creep up tree trunks. The spread of the treecreeper is the northern, eastern and central Europe and eastwards through Russia and Central Asia to the Pacific Coast and Japan. The treecreeper appears especially in hardwoods and parks, but also in older coniferus forests, the species is especially numerous in old nature-forest, where 20-40 couple can breed pr. km2. The treecreeper is relatively mobile and is found all over the Denmark, including most small islands. During the last decades of the 20th century it was during expansion, especially in the northern Jutland and upon the western Lolland. This might be connected to the mild winters of the 1990s and partly an ageing of the north Jutland forests, which made them more suitable for the treecreeper.
The treecreeper is a strejf-fugl which means that it is roaming inside its area without being a migration bird. It stays in Denmark in winter, where it is often seen in mixed flocks with tits. Birds from northern populations are seen in migrations, especially on the island Bornholm, in spring and autumn. In cold winters the treecreepers often overnight close together to keep the warmth, and in very hard winters the mortality is high. The overwintering means that the treecreeper already in the end of February starts the breeding-activity, and the singing is at its highest in the middle of March. It begins to build the nest in late April, and it is typically placed in holes in old trees or under large pieces of loose bark.
Breeding couple in Denmark in 2000: 15.000-25.000
Source: Natur og Fugle, Dansk Ornitologisk Forening
photo Klostermølle 10. March 2012: grethe bachmann