The Willow Tit (Poecile montanus) is a tiny tit, just 12–13 cm long with a wingspan of about 17–20 cm and a weight of only 9–12 g. It has brown-grey upperparts, warm beige flanks and a matte black crown extending down into the nape, with a relatively large, somewhat diffuse black chin patch. A useful field mark is a pale panel on the wing, formed by pale edges on the secondary feathers, which the very similar Marsh Tit lacks — though the two species are so alike that voice is often the surest way to tell them apart.
Its most common call is a nasal, drawn-out "dää-dää-dää," often introduced by a few thinner notes, quite unlike the Marsh Tit's sharp, explosive "pit-chäää"; the song is a series of clear, somewhat mournful whistles. Unusually among tits, the Willow Tit excavates its own nest hole, usually in rotten wood in a stump, low trunk or dead deciduous tree such as birch or alder, and rarely takes ordinary nest boxes, making it dependent on a supply of dead wood in the forest. The female lays 6–9 eggs and incubates them for 13–15 days, with the young fledging just over two weeks after hatching. Its diet consists of insects, spiders, larvae and seeds, and it is a diligent hoarder, caching individual seeds by the thousand in bark and lichen each autumn and remembering their locations with remarkable precision; in winter it often joins roaming flocks with Great Tits, Goldcrests and Treecreepers. Found across Sweden, most numerous in the large coniferous forests of Norrland and central Sweden, the resident population — numbering several hundred thousand pairs — is declining, particularly in the south, and the species is classified as Near Threatened, largely because modern forestry leaves fewer dead and rotting trees for it to excavate.
Read about this species in Swedish →