Key points
- Badger numbers have increased in recent years, raising concern about their impact on ground-nesting birds.
- Although badgers mainly feed on earthworms, cold and dry conditions can reduce worm availability and prompt them to take alternative prey.
- This study examined how weather and habitat factors influence badger predation on lapwing nests at GWCT’s Scottish demonstration farm, Auchnerran.
- Nest cameras recorded predation events, and statistical models tested links between weather, invertebrate availability, and land use.
- Weather emerged as a key driver. Badgers were far more likely to take lapwing eggs during cold, when earthworms (their staple prey) were less available at the soil surface.
- The likelihood of badger predation was greatest at 4°C or lower, and almost zero above 10°C.
- These findings suggest that weather forecasting could inform targeted, pre-emptive predator management to help protect vulnerable wader populations such as lapwing.
Background
Populations of wading birds, or waders, have declined sharply in recent years. This concerning drop in numbers signals wider issues for the delicate habitat they rely on. Driven by historic agricultural intensification, wetland drainage and recent rises in generalist predator numbers, the steepest declining species are found in Western Europe. The Eurasian
curlew, Eurasian oystercatcher and northern lapwing are among the farmland waders most affected, with lapwing showing steep declines across the UK, including a 63% drop in their Scottish breeding population since the mid-1990s.
As nest losses to predation have risen over the past 70 years, species such as foxes and corvids have been widely recognised as major threats to wader eggs and chicks.
Badgers are omnivorous and opportunistic but do not typically rely so heavily on wader nests for food, although studies have shown that they will eat eggs opportunistically. This can have locally significant impacts on vulnerable ground-nesting species. In some reserves, evidence suggests that badger predation can account for around 13% of wader nest losses but the drivers for this have been unclear.
Badgers’ diet can vary in different regions of the world but they mostly feed on earthworms and large insects. These invertebrates are most accessible in warm, moist conditions. In cold or dry weather they switch to alternative foods. Wet grassland habitats are favoured by waders for nesting, and badgers for foraging. , This means changes in climate, weather and food availability might bring them into greater contact during the breeding season, therefore potentially increasing nest predation.
This study set out to investigate the conditions under which badgers are most likely to predate lapwing nests on a Scottish farm with high lapwing breeding densities. It focused on the roles of weather, invertebrate abundance, and land use, with the aim of understanding how environmental variability influences interactions between badgers and nesting waders.
What they did
The study was conducted on the Game and Wildlife Scottish Demonstration Farm, Auchnerran. The farm is mainly grass-dominated hill-edge habitat, similar to many sheep farms across Scotland. Records collected between 2018 and 2021 from camera traps estimated a minimum count of eight badgers on the farm. More consistent monitoring between 2021 and 2023 revealed three newly occupied setts in 2021 but the population was estimated to remain stable.
Each spring and summer (March–July, 2018–2023), researchers searched farm fields for lapwing nests using vehicle surveys and knowledge of favoured nesting areas. For each nest, details such as date, location, number of eggs, nest stage/outcome, and cause of failure were recorded digitally. When nests failed, field signs (e.g. clutch removal, nest destruction, claw marks) and, where available, trail cameras were used to identify predators.
Nests were marked with small stakes placed a minimum of 1.5 meters away, and most checks were done from 100–150 m with binoculars or telescopes. Broods were monitored after hatching where possible, using colour rings and regular whole-farm surveys to record chicks and adults. Final counts were made soon after fledging to avoid including birds from neighbouring areas.
Between 2018 and 2021, a small number of nests were fitted with cameras. From 2022 onwards, more cameras were available, so a greater proportion of nests could be monitored this way. Images provided clear evidence of hatching, failure, and predators.
Weather data (temperature and rainfall) were recorded from an on-site weather station for the 7 and 30 days before each nest hatched or failed. Farm records provided land management information, including agri-environment scheme classifications. Invertebrate abundance, measured from soil samples in 2018, 2019 and 2021, was also included as a potential factor influencing badger behaviour, with particular attention to earthworms.
Statistical models were used to test which factors best explained nest success and failure. Because invertebrate data were only available for part of the study, the analysis was carried out in two stages: first using all nests without food data, then repeating with the smaller dataset that included invertebrate measures. This approach allowed the researchers to estimate the probability of nest success and different failure types, and how these varied between years and under different conditions.
What they found
Overall, 372 nesting attempts were suitable for analysis. Of these 208 were monitored using trail cameras and the fledging success of the remaining 164 were assigned using field signs. Around 1 in 4 predation instances were by badgers. A total of 90 clutches were taken by predators across the investigation and 23 of these were predated by badgers. Of these 23 predation events, 21 of these occurred in 2021 coinciding with abnormally cold spring.
Weather emerged as a key driver. Badgers were far more likely to take lapwing eggs during cold, when earthworms (their staple prey) were less available at the soil surface. The likelihood of badger predation was greatest at 4°C or lower, and almost zero above 10°C. Badgers are likely to forage further for longer in these conditions, therefore lapwing nests are thought to provide a convenient alternative food source. Whereas, in wetter and milder weather, badgers had little impact on lapwing nests, as their preferred prey was more abundant.
Nest location also mattered. Fields closer to occupied badger setts saw a higher rate of nest losses, suggesting that proximity to badger activity areas increases risk for breeding waders. The study also noted that while foxes and corvids remain the most regular nest predators UK-wide, badger impacts could still be significant in certain years or under particular weather patterns.
What does this mean?
These findings highlight the complex and context-dependent role of badgers as nest predators of lapwings. While they are not specialist predators of ground-nesting birds, their opportunistic feeding can pose a real threat when environmental conditions reduce their access to preferred prey. For prey species with already vulnerable populations, even slight increases in predation from novel species like badgers can have disproportionately large impact.
This study supports other research in underlining how weather and climate interact with predator behaviour and prey vulnerability. While rainfall was not found to have a significant effect on the likelihood of badger predation on the nests, other studies in the south of England have found an effect.Dry or cold springs may therefore bring added pressure to already declining wader populations, particularly in areas where badgers and waders share grassland habitats.
As climate change is expected to increase the frequency of extreme dry or cold spells in spring, badger predation could become a more prominent factor influencing breeding success for some wader populations. For conservationists and land managers, this emphasises the need for flexible, locally tailored approaches to managing farmland habitats – accounting not only for predator numbers but also for how environmental variability shapes their impacts. This study highlights the opportunity to utilise weather forecasting for pre-emptive predator management strategies to maximise their effectiveness.
In short, badgers may not be the primary cause of wader declines, but under certain conditions they can contribute significantly to nest losses. Understanding these dynamics is vital for designing effective strategies to support the recovery of vulnerable species such as lapwing.
Tolhurst, B. A. et al. Temperature drives inter‐annual variation in badger Meles meles predation of lapwing Vanellus vanellus on Scottish hill‐edge farmland. J. Avian Biol. 2025, 1–15 (2025).