63 saltmarsh sites were surveyed, representing around 5% of the total area of saltmarsh in Britain. Sites were selected to include a range of saltmarsh habitats evenly distributed around Britain. No formal random sampling protocol was used to select sites. The entire dataset is presented at 100m resolution. Data points for this dataset represent the central point of the site surveyed.
The survey was carried out in the 1996 breeding season (between 15 April and 31 May).
Numbers of redshank breeding at each site were measured using standard methods developed by Green et al. (1984) and Green (1986). The mean number of redshank counted on survey visits up to 31 May was used as an estimate of the peak number of pairs with nests. The abundance of other species such as wildfowl and other waders were also captured as part of this survey, but these data do not occur as part of this dataset. These data have been gathered by trained field-workers and are therefore of a high quality. These data have also been mapped and checked for sensitivities and typographical/geographical errors.
This survey highlighted that saltmarshes support circa 45% of the national population of redshank breeding in Britain. Since a previous survey carried out in 1985, there has been a 22.9% decline of redshank breeding on saltmarshes. The decline is thought to be caused by an increase in grazing pressure of saltmarshes, it was therefore suggested that mitigation procedures such as habitat creation and changes in agricultural management measures were required.