Willow Tit habitats vary across the UK and Europe. In Northern Europe they favour conifer forests where they forage in winter during heavy snowfall, while during the breeding season they nest in areas with more birch trees on peaty soils. In the UK they are associated with a number of scrubby habitats, which may include overgrown hedges on river valleys and floodplains, young regrowth in conifer plantations, birch and willow scrub on former industrial sites, linear scrub along railway lines and canals, or scrubby areas on the edge of mature plantation or woodland. A key feature of these sites is the prevalence of pioneer tree and shrub species such as willow, birch, elder and hawthorn with few mature canopy trees. These sites are often but not exclusively on wetter areas.
Based on earlier research, the key properties of Willow Tit habitat are:
- Dominant tree/shrub species: Hawthorn, Elder, Alder, Birch, Willows.
- Undesirable tree species: Oak, Beech, Sycamore, Mature Conifers (where there is little or no shrub layer).
- Shrub cover at 2-4m above ground: 46-58%.
- Canopy cover: 48-58%.
- Lots of standing small dead trees, 10-20 cm diameter.
- Younger woods preferred but only if they contain favoured tree species and not undesirable tree species.
- Wetter soils preferred, which retain moisture for longer during the breeding season. i.e. poorly draining soils, or peat soils.
- Patches of suitable habitat can be as small as 1ha for breeding as they will use surrounding habitats and move between patches.
Willow Tits excavate holes in soft rotten stumps to nest in; they may excavate more than one hole before deciding where to nest. Nests site characteristics are:
- Height above ground 1-2.5m.
- Trunk diameter 10-20 cm.
- Tree species used for nests: willow (16%), birch (40%), elder (15%), + 24 other species.
- Elder used for nesting more frequently than found in habitat and Hawthorn less
Glamorgan Willow Tit Project 