Willow Tit

The willow tit (Poecile montanus) is a small northern tit found from Scandinavia across the taiga of Eurasia, with more fragmented populations in temperate and mountainous areas farther south. Adults are about 11.5 cm long and weigh around 10 g. The plumage is subdued, with a matte black cap and bib, white cheeks, brown-grey upperparts and pale underparts.

It is famously difficult to separate from the marsh tit (Poecile palustris) by appearance alone. Voice is usually the safest field character: willow tits give a characteristic nasal, buzzing call, while visual tendencies include a larger black bib, a duller cap and a pale panel on the folded wing. None of the plumage features is completely reliable by itself.

Willow tits inhabit boreal coniferous and mixed woodland, mountain birch forest and damp woodland with willow, alder or birch. Structurally varied forest is especially valuable because the birds need both good feeding habitat and soft, decaying stems in which they can excavate nest cavities.

A large Finnish study published in 2024 found that both breeding and winter numbers were higher where there was more older forest. Forest age and structure therefore matter even though willow tits can occupy several different woodland types.

Insects, larvae and spiders dominate the diet during the warmer months, while seeds become increasingly important in autumn and winter. Birds search bark, twigs, foliage and other vegetation and also take food from the ground.

Established adults are strongly resident and often remain within the same territory throughout the year. Familiarity with a small area is especially useful in winter, when the birds depend not only on food they find directly but also on thousands of small stores hidden around their home range.

Food storage is an important part of the willow tit’s winter strategy. A five-autumn Swedish study published in 1994 estimated that an individual stored about 46,300 seeds over an autumn. Earlier estimates of 50,000–80,000 stored food items came from years with unusually rich spruce seed crops and may have been high. Even so, the stored seeds alone were estimated to provide about 85% of a bird’s energy needs in December and around a quarter from January through March in the relatively mild winters studied.

Social conditions also affect where food is hidden. In field experiments in Finland, subordinate birds cached food farther from a temporary feeder when dominant flock members were present. When the dominant birds were temporarily removed, the subordinates began caching closer to the feeder and stored food more frequently. Willow tits therefore adjust where they hide food in ways that can make the caches harder for competitors to find.

Willow tits usually excavate their own nesting cavity in soft, rotten wood, often in dead or decaying birch, alder or other small trees. Unlike a woodpecker they cannot excavate sound, hard wood, making suitably decomposed stems an important habitat requirement. Both adults can take part in excavation, after which the cavity is lined with soft plant material, hair, feathers and similar fibres.

A typical clutch contains 6–8 eggs. The female incubates for about 14 days, while both parents feed the young, which normally leave the cavity after about 17–20 days. One brood is typical. Young birds disperse after becoming independent, whereas established adults are much more sedentary.

The willow tit is classified as least concern on the IUCN Red List. It retains a very large Eurasian range, but substantial declines have occurred in several parts of Europe.

The Finnish study published in 2024 found that adult survival had fallen strongly during the population decline, while the number of new birds entering the population showed no comparable fall. Changes in great tit and great spotted woodpecker numbers did not explain the large-scale decline. Loss of older forest and reduced habitat quality in areas with increasing logging fitted the population trend much more closely than competition alone.

The 2025 update from the Pan-European Common Bird Monitoring Scheme, based on data through 2024, shows a 76% decline in the European breeding index from 1980 to 2024 and a 23% decline in 2015–2024. The species remains globally widespread, but the European trend is strongly negative.