Resident, strongly sedentary
Principal Biodiversity Species in Wales
The Population Status of Birds in Wales:
Population trend and distribution
A resident species, widespread but patchily distributed, with an easterly bias in Wales (Lovegrove et al. 1996). Marsh tits have undergone a rapid decline over the last 25 years in both Wales and the UK. The RWBS showed declines of 6.1% (the RSPB) and 39.4% (BTO) in Wales since the 1980s (Amar et al. 2006) but these figures should be treated with caution due to small sample sizes. For the UK as a whole, information on trends is conflicting; the RWBS shows both a 26.5% increase (the RSPB) and 27% decrease (BTO), and the BBS a decrease of 6% between 1994 and 2007.
Mar Apr May
General: marsh tits prefer mature, deciduous woodland; a well-developed shrub layer is key. They will use wooded riverside habitat, eg alder carr and well- developed parkland or wood pasture, but intensively managed commercial woodland, eg conifer plantation is avoided. They require large woodland patches with a good proportion of naturally occurring nestholes in mature trees; 2–3 ha is the minimum size for successful nesting, but as much as 10 ha may be needed to fulfil winter requirements.
Nesting: holes and splits in sound trees, large stumps, and coppice stools are used. Nests are often high, eg 5.5 m in larger trees. Rotten wood is avoided and nestboxes are only occasionally used. They do not excavate their own holes, but will expand or reshape existing holes.
Feeding: insects and spiders taken from leaves and twigs, and amongst lichen or bark crevices, usually in the lower canopy and shrub layer. Seeds, berries and nuts supplement the diet, and can be preferred to invertebrates outside of the breeding season. Beech mast is often taken when available. Seeds are collected from the ground, and from late summer are cached for a few days among leaf litter, on dead stumps or under moss or lichen.
Marsh tit populations prefer larger woodlands and are negatively affected by woodland isolation and fragmentation (Amar et al. 2006). They seldom persist through the winter in areas with only small woodlands, possibly due to a lack of feeding opportunities (Perrins 2003).
Increased grazing pressure causing a reduction in shrub layer structure and
33 Rapid (>50%) decline in UK breeding population over the last 25 years with no evidence to suggest that Welsh population has not declined in parallel. 34 Preliminary assessment for 2008 revision of The Population Status of Birds in Wales: Red-listed.
Figure 32 Key areas for marsh tit in Wales.