The dataset records the annual number of occupied Marsh Tit breeding territories in 74 individual woods and woodland patches in 14 English counties for variable periods between 2002 and 2020. Different woods were surveyed from between one spring period and for up to 17 annual springs. Territory counts were derived from a standard highly-repeatable survey methodology or from more intensive population studies that produced high quality results. Marsh Tits are a small (10 g) songbird that are specialists of mature deciduous and mixed woodlands and have undergone a substantial population decline in Britain over recent decades. Because of their large territories, Marsh Tits are difficult to monitor by passive surveys, and so these specific and more accurate methodologies were used. This data can be used to compare with other woods using the same or a comparable methodology, investigate population trends or population-habitat relationships, or to monitor population change in future repeat surveys of the same woods. The data is georeferenced and each of the 237 individual records provides the Great Britain Ordnance Survey (OSGB) National Grid x and y coordinates of the surveyed wood, and also the woodland area surveyed, name and location (county name) of the wood, year of survey, woodland type and survey method. Full details about this dataset can be found at https://doi.org/10.5285/8d1b93d7-b8cf-4df1-9a5d-352dc16c5195
