The Wash is England’s largest Special Protection Area, with Oystercatchers being a designated feature. During the winter, Oystercatchers rely heavily on Cockles and Blue Mussels for their food requirements, creating the potential for conflict with the human fisheries for these species.

Periodic surveys of machair and associated habitats on the west coast of North Uist, Benbecula and South Uist have documented marked changes in the composition of an important breeding wader assemblage. Within the study area of there was a 25% decline in the total number of breeding waders recorded between 1983 and 2022.

The future of Britain’s breeding wader populations depends on land use policy and local management decisions, both of which require robust evidence and appropriate tools if they are to support the conservation of these priority species. One of the biggest challenges has been the geographical scale at which national data on wader abundance and distribution are available. These data are coarse in their resolution, making them poorly suited to directing conservation initiatives or informing land management decisions at a local scale. But can a statistical approach produce high-resolution maps of predicted wader abundance that are sufficiently accurate to be used for decision-making?

Breeding waders in Britain are high profile species of conservation concern because of their declining populations and the international significance of some of their populations. Forest expansion is one of the most important, ongoing and large-scale changes in land use that can provide conservation and wider environmental benefits, but also adversely affect populations of breeding waders. We describe models to be used towards the development of tools to guide, inform and minimise conflict between wader conservation and forest expansion. Extensive data on breeding wader occurrence is typically available at spatial scales that are too coarse to best inform waderconservation and forestry stakeholders. Using statistical models (random forest regression trees) we model the predicted relative abundances of 10 species of breeding wader across Britain at 1-km square resolution. Bird data are taken from Bird Atlas 2007–11, which was a joint project between BTO, BirdWatch Ireland and the Scottish Ornithologists’ Club, and modelled with a range of environmental data sets.

Protected sites for birds are typically designated based on the site’s importance for the species that use it. For example, sites may be selected as Special Protection Areas (under the European Union Directive on the Conservation of Wild Birds) if they support more than 1% of a given national or international population of a species or an assemblage of over 20,000 waterbirds or seabirds. However, through the impacts of changing climates, habitat loss and invasive species, the way species use sites may change. As populations increase, abundance at existing sites may go up or new sites may be colonized. Similarly, as populations decrease, abundance at occupied sites may go down, or some sites may be abandoned. Determining how bird populations are spread across protected sites, and how changes in populations may affect this, is essential to making sure that they remain protected in the future. These findings come from a new study by Verónica Méndez and colleagues from the University of East Anglia working with BTO. Using Wetland Bird Survey (WeBS) data the study looked at changes in the population sizes and distributions of 19 waterbird species across Britain during a period of 26 years and their effect on local abundance and site occupancy. Some of these species saw steady increases in population size (up to 1,600%, Avocet), whereas other saw mild declines (-26%, Purple Sandpiper and Shelduck). The results showed that changes in total population size were predominantly reflected in changes in local abundance, rather than through the addition or loss of sites. This is possibly because waterbirds tend to be long-lived birds, with high site fidelity and new suitable sites may not always be available. Thus colonisation of new sites may typically occur when their existing sites approach their maximum capacity. As changes in populations are largely manifested by changes in local abundance – and as sites are often designated for many species – the numbers of sites qualifying for site designation are unlikely to be affected. Understanding the dynamic between population change and change in local abundance will be key to ensuring the efficiency of protected area management and ensuring that populations are adequately protected. Data from the Wetland Bird Survey and its predecessor schemes, which are celebrating 70 years of continuous monitoring of waterbirds this year, have been integral to both the designation of protected sites and monitoring of their condition. Continuation of this monitoring through future generations will ensure that the impacts to waterbird populations of future environmental changes may be understood.

The breeding populations of many different wader species are in decline across the globe, and the UK is no exception. These declines have been linked to increased predator numbers, changes in agricultural practices, and in the management of the wider landscape. There is an urgent need for information on how such changes in land management, particularly within farmland, may affect breeding waders. This information can then be used to inform future land management decisions. Long-term studies can make an important contribution to our understanding of wader decline, as is demonstrated by work carried out by BTO’s Regional representative for Perthshire, Mike Bell. Mike had the foresight to start monitoring what was an important concentration of breeding waders in Strathallan (Perthshire, Scotland) in the late 1980s. Twenty-five years after establishing repeatable methods over the study area proved an appropriate time to take stock of changes that occurred. The four most numerous species in the area were Oystercatcher, Lapwing, Curlew and Redshank, which respectively achieved densities of 12, 36, 3 and 5 pairs per km2 in 1990. All are facing serious declines across the UK. Alongside information on the breeding populations of these four waders, Mike also documented agricultural changes; from this it was possible to determine how local farming practices were likely to have influenced the waders. Over the period of 1990-2015 Oystercatchers showed the greatest proportional decline with the breeding population falling by 95%, followed by Lapwing (-88%), Redshank (-87%) and Curlew (-67%). Although the greatest declines were associated with changing land use, the declines appeared greater than could be accounted by losses of preferred habitat alone. Furthermore, breeding success was low throughout the study and probably not sufficient to maintain the population. This raises the importance of understanding the roles of source and sink populations for breeding waders in the wider countryside. Alongside this, threats from poor weather, increased disturbance (e.g. from dog walkers), and increased predator numbers could further implicate the population, although this was not studied specifically at Strathallan. Mike Bell is a long-term volunteer for the BTO and now Regional Representative for Perthshire. This 25-year (and ongoing) study was undertaken in his own time, highlighting the value of volunteers to science and conservation. It also emphasises how long-term datasets such as this can provide invaluable insights into the pressures that bird species are facing, and how we may alleviate these pressures. As most long-term studies are possible only with volunteers, the importance of their contribution is increasingly important. With support from the BTO’s recent Curlew Appeal, BTO has been trialling a range of approaches where volunteers can add to our understanding of the ecology of breeding waders, knowledge which will be vital to provide these beautiful birds with a fighting chance.