The work was funded by Forestry Commission England (Neil Riddle as nominated officer), the Cairngorms National Park Authority, Scottish Forestry and RSPB (Pete Mayhew as nominated officer) and Scottish Natural Heritage (SNH) through the Working for Waders partnership. The analyses draw heavily on earlier work funded by Scottish Forestry (Colin Edwards as nominated officer) and by the Joint Nature Conservation Committee (JNCC). Bird Atlases were a partnership between BTO, the Scottish Ornithologists’ Club and Birdwatch Ireland and BBS between BTO, JNCC and RSPB; we are indebted to the many volunteers who contributed to the fieldwork. Other data has been provided by the Shetland Biodiversity Records Centre (Paul Harvey), RSPB (Allan Perkins, Robin Sinclair) and Natural England (Allan Drewitt). Many others have contributed to discussions guiding this work: Mark Broadmeadow and Jim O’Neill (Forestry Commission England); David Hetherington, Will Boyd-Wallis and Mike Cottam (CNPA); Allan Drewitt, Adrian Jowitt and Robert Cussen (Natural England); Jess Findlay, Alastair McGugan and Jeanette Hall (SNH), Allan Perkins,  Chris Bailey, Paul Bellamy, Dan Tomes, Alison Phillip, David Douglas and Duncan Orr-Ewing (RSPB), Scott Newey (JHI), Ross McLeod (GWCT), Andy Tharme (Scottish Borders Council); Sam Franks, Rachel Taylor, James Pearce-Higgins, David Jarrett, Chris Wernham (BTO).

Breeding waders are high profile species of conservation concern because of their declining populations. Their future depends on the outcomes of land-use policy and local management decisions. However, the low spatial resolution of extensive data on wader occurrence is poorly suited to directing conservation initiatives or to minimising detrimental impacts arising from land-use changes such as forest expansion. We used statistical models to produce high-resolution maps of predicted wader abundance in Britain and tested whether these were sufficiently accurate to be used for decision making. Random forest regression trees were developed using Bird Atlas data modelled with a range of environmental data sets to predict the relative abundances of ten species of breeding wader across Britain at 1-km square resolution. Similar analytical frameworks could usefully be applied in other geographical areas.

Correlations with Bird Atlas metrics and other independent data indicate that these predictive models worked best for Curlew Numenius arquata and Oystercatcher Haematopus ostralegus.  Model performance was poorer for species with more restricted distributions and/or habitat requirements, such as Greenshank Tringa nebularia and Ringed Plover Charadrius hiaticula. The precision of model predictions was also limited by the rescaling of data to 1-km square resolution.

To facilitate practical and consistent interpretation by stakeholders influencing the status of breeding waders, model outputs were categorised into five discrete strata of relative abundance. These strata were used to produce sensitivity maps (available at https://app.bto.org/wader-map/), primarily to inform high-level policy decisions. The model outputs were also used to investigate broad-scale associations of breeding wader distribution with landscapes and land uses. These show that high proportions of populations (relative to their extent) are supported by areas with comparatively low predation risk (e.g. islands and grouse moors) and also by nature reserves. At more local scales, the sensitivity maps can be used to help decide on the levels of scrutiny required to assess development proposals (e.g. for establishment of new tree planting).