Marsh Tit abundance has declined almost continuously since BTO monitoring began. The species' UK conservation listing has recently been upgraded from amber to red. Detailed demographic work suggests that the decline may have been driven by low annual survival, and that neither increased predation nor interspecific competition is responsible (Siriwardena 2006). Nest failure rates have fallen during the period of decline. Marsh Tits nest in woods as small as half a hectare (Hinsley et al. 1995), but there is evidence from CBC that declines are steeper on smaller plots (G.M. Siriwardena, unpubl.). Reductions in the structural and floristic diversity of woodland, resulting partly from increased browsing by deer, are likely to have caused the decline (Perrins 2003, Fuller et al. 2005). Marsh Tits appear to select breeding territories on the quality of the shrub layer rather than the tree canopy, and may be adversely affected by factors that damage the shrub layer, such as overgrazing and canopy closure (Hinsley et al. 2007). Numbers have fallen widely in Europe since 1980 (PECBMS 2007). Following declines elsewhere in western Europe during the 1990s, the European status of this species is no longer considered 'secure' (BirdLife International 2004).

Population changes

Productivity trends

Additional information

• Maps and statistics from British and Irish atlases
• BirdFacts page on species biology
• BirdTrack results
• Garden BirdWatch results