Capsule: The UK breeding population estimate comprised 50,750 male Eurasian Woodcocks (95% CI: 42,935-59,251) in Britain and 937 males (95% CI: 274-1714) in Northern Ireland. The British population has continued to decline since 2013. Aim: To produce UK, British and regional estimates of breeding population size for Eurasian Woodcocks, and to assess the population change since 2003. Methods: The 2023 Breeding Woodcock Survey enlisted volunteer surveyors to count birds across a stratified sample of 1230 squares in England, Scotland, Wales, and Northern Ireland. The established 'roding count' methodology consists of up to three dusk visits, each lasting 75 min, during May and/or June. The results were used to calculate presence and mean density across 48 strata based on wooded area and regions, and extrapolated to produce regional and national estimates of population size. Results: The population in Britain in 2023 was estimated at 50,750 male Woodcocks (95 CI: 42,935-59,251), representing an 8% decline since 2013, and a 35% decline since 2003. Despite small population increases in Wales and England since 2013, the continuing decline was driven by a 49.5% reduction in the population estimate for North Scotland. In 2023, Northern Ireland's breeding population of Eurasian Woodcocks was estimated at 937 males (95% CI: 274-1714), which is the first estimate produced using this species-specific method. Conclusion: Nationally, populations of Eurasian Woodcocks continue to decline, but the 2013-2023 declines were not as severe as those recorded between 2003 and 2013. The diverging population trends between North Scotland and the rest of Britain raise questions regarding regional variation in habitat suitability/availability and factors influencing overwinter survival. Recommendations are made for future versions of the Breeding Woodcock Survey regarding the composition of the random sample of squares, the treatment of incomplete data, and the sampling of non-woodland habitat.

Capsule: Small mammal abundance was greatest in landscapes with a high coverage of grassy field margins, which was also associated with increased fledging success of Barn Owls. Aims: To determine the potential value of agri-environment scheme (AES) habitats for small mammals and, in turn, predatory Barn Owls. Methods: Monitoring of small mammals was conducted across 14 1-km(2) British National Grid squares. Survey squares were selected according to a known distribution of Barn Owls derived from monitoring during 2018-2020. We analysed relationships between small mammal activity and coverage of grass-dominated field margins, floristic margins, hedgerows, and tree lines. Barn Owl nest box occupancy in 2021 was analysed in relation to prey abundance (small mammal activity) and the described habitat types. Barn Owl fledging success was then modelled in relation to the prey abundance and the coverage of different habitat types. Results: Our findings suggest that grass field margin habitats are among the AES options most likely to be of value to Barn Owls, as positive relationships with fledging success and prey species were identified. This research is important in providing evidence to support continued implementation and valuing of grass margins under future versions of AES. Conclusion: The study findings suggest that breeding Barn Owls benefit from the provision of grassy field margin habitat, more so than those sown with wildflowers. Our findings add to the body of evidence demonstrating the positive relationships between AES and wildlife and support continued implementation of grass margins on arable farmland.

Use of species-specific field methods may be required for taxa that are inherently difficult to survey, for example species with cryptic camouflage or secretive behaviour. However, these methods often require more manual effort and therefore cost. Passive acoustic monitoring (PAM) is now an established tool to reduce manual effort to monitor species, and analysis of spectrograms provides the means to discriminate individuals by call characteristics. At night, male Eurasian Woodcock Scolopax rusticola make distinct, audible 'roding' displays above the tree canopy to advertise to females. Studying this behaviour at an individual level while using PAM presents opportunities to improve monitoring methods of this cryptic, Red-Listed species. This study evaluates the potential use of vocal individuality measurements in distinguishing Woodcock individuals and interpreting spatial and temporal patterns in their roding displays across woodland sites. Woodcock roding calls were recorded from woodland fragments across two regions comprising 20 sites. A random forest classifier was applied to reduce the time needed to find and manually verify calls. Principal component analysis (PCA) and hierarchical clustering algorithms were used on call measurements, describing duration and frequency differences in calls. When clusters formed, they were used to qualitatively assess supposed individual spatial and temporal variation in roding behaviour. The variance of dimensionally reduced measurements was used to interpret local Woodcock abundance and changes over time. Supposed individuals used many sites within a region, and many sites were used by multiple birds. However, sites showed clusters of calls from supposed individuals in different proportions. It was difficult to discriminate individuals using PCA with more than six birds because the degree of call overlap increased. Though the call measurement variance is associated with number of call events, it may provide a suitable method for representing population size without call count bias.

Counts of displaying male Eurasian woodcock (Scolopax rusticola) form the basis for breeding Eurasian woodcock surveys in many regions across Europe and provide the only practical method of assessing the species’ abundance. This paper investigates the effect that weather may have on the results of these surveys, principally considering its influence upon Eurasian woodcock display behavior and detectability by surveyors. We assessed data from an annual Eurasian woodcock survey conducted in the Britain during 2004–2015 and correlated them with a number of weather variables. This is supplemented by tracking data gathered from 19 male Eurasian woodcock to assess how weather might affect each individual’s decision to display. We found that counts of roding Eurasian woodcock were positively related to the amount of rainfall in the 2 weeks preceding the survey and negatively related to wind speed on the evenings that surveys were conducted. The likelihood that tagged male Eurasian woodcock displayed decreased in relation to wind speed and increased in relation to minimum air temperature. To guarantee that counts of displaying males provide a representative measure of abundance, we recommend that surveys consist of at ≥3 visits to each site within each year, that visits are spread as widely as possible across the peak displaying season, and that analyses are based on maximal counts rather than means to reduce the effects of surveys conducted in sub-optimal weather conditions.

Migration is a critical period of time with fitness consequences for birds. The development of tracking technologies now allows researchers to examine how different aspects of bird migration affect population dynamics. Weather conditions experienced during migration are expected to influence movements and, subsequently, the timing of arrival and the energetic costs involved. We analysed satellite‐tracking data from 68 Eurasian Woodcock Scolopax rusticola fitted with Argos satellite tags in the British Isles and France (2012–17). First, we evaluated the effect of weather conditions (temperature, humidity, wind speed and direction, atmospheric stability and visibility) on migration movements of individuals. Then we investigated the consequences for breeding success (age ratio) and brood precocity (early‐brood ratio) population‐level indices while accounting for climatic variables on the breeding grounds. Air temperature, wind and relative humidity were the main variables related to migration movements, with high temperatures and northward winds greatly increasing the probability of onward flights, whereas a trend towards greater humidity over 4 days decreased the probability of movement. Breeding success was mostly affected by climatic variables on the breeding grounds. The proportion of juveniles in autumn was negatively correlated with temperature in May, but positively correlated with precipitation in June and July. Brood precocity was poorly explained by the covariates used in this study. Our data for the Eurasian Woodcock indicate that, although weather conditions during spring migration affect migration movements, they do not have a major influence on subsequent breeding success.

Migration represents a critical time in the annual cycle of Eurasian woodcock ( Scolopax rusticola ), with potential consequences for individual fitness and survival. In October–December, Eurasian woodcock migrate from breeding grounds in northern Eurasia over thousands of kilometres to western Europe, returning in March–May. The species is widely hunted in Europe, with 2.3–3.5 million individuals shot per year; hence, an understanding of the timing of migration and routes taken is an essential part of developing sustainable flyway management. Our aims were to determine the timing and migration routes of Eurasian woodcock wintering in Britain and Ireland, and to assess the degree of connectivity between breeding and wintering sites. We present data from 52 Eurasian woodcock fitted with satellite tags in late winter 2012–2016, which indicate that the timing of spring departure varied annually and was positively correlated with temperature, with a mean departure date of 26 March (± 1.4 days SE). Spring migration distances averaged 2,851 ± 165 km (SE), with individuals typically making 5 stopovers. The majority of our sample of tagged Eurasian woodcock migrated to breeding sites in northwestern Russia (54%), with smaller proportions breeding in Denmark, Scandinavia, and Finland (29%); Poland, Latvia, and Belarus (9.5%); and central Russia (7.5%). The accumulated migration routes of tagged individuals suggest a main flyway for Eurasian woodcock wintering in Britain and Ireland through Belgium, the Netherlands, and Germany, and then dividing to pass through the countries immediately north and south of the Baltic Sea. We found a weak positive relationship between breeding site longitude and wintering site latitude, suggesting broadly parallel migration routes from distinct breeding areas but some mixing of individuals from different breeding areas at the same wintering site.

In Europe, woodland bird populations have been declining since at least the 1970s, and in Britain, around one third of woodland bird species have undergone declines over this period. Habitat change has been highlighted as a possible cause, but for some species clear evidence of this is lacking owing to an incomplete knowledge of the species' habitat requirements. Here, we analyse national data to explain the variation in abundance of a declining woodland bird, the Eurasian Woodcock. A nationwide, species-specific survey of breeding Woodcock was conducted in 2003 and 2013 at 807 and 823 randomly selected 1-km squares respectively. The counts were compared with a range of landscape-scale habitat variables as well as local habitat measures recorded by surveyors, using generalised linear mixed models. Habitat variables were measured at a variety of spatial scales using ring buffers, although our analyses show that strong collinearity between scales hinders interpretation. At large landscape scales, breeding Woodcock abundance was correlated with total woodland area and the way this interacted with woodland type. Woodcock were more abundant in woods containing a more heterogeneous mix of woodland habitat types and in woods further from urban areas. On a smaller spatial scale, Woodcock were less likely to be found at sites dominated by beech Fagus spp. and more likely to occur in woods containing birch Betula spp. The Woodcock's association with large, heterogeneous woods and the apparent attractiveness of certain woodland types present the most relevant topics for future research into the role of habitat change in long-term declines.

We describe a method for mist-netting Eurasian Woodcock Scolopax rusticola in the breeding season using a remote-control playback lure and a decoy. Nineteen roding woodcock were caught in 39 sessions in 2016. A GLM, in which length of mist-net was specified as an offset, was used to compare our capture rate to that of a previous study in which no lure was used, suggesting our 'number of captures per session' was approximately nine times higher. Ringing individuals that are known to belong to Britain's resident breeding population could provide more comprehensive data, which are of particular value given this population's ongoing decline.

Capsule The breeding Woodcock population in Britain in 2013 was estimated at 55241 males (95% CL: 41806-69004), suggesting a large-scale decline that is supported by 2 additional sources of data.Aims To provide an updated estimate of the size of Britain's breeding Woodcock population, measure recent trends and identify spatial patterns of change.Methods Displaying male Woodcock were surveyed at a stratified sample of 834 randomly selected sites. Population estimates were compared with a baseline survey conducted in 2003 and the trend with data from annual Woodcock counts (2003-13) and Bird Atlas 2007-11.Results Woodcock were estimated to be present at 22% of 1x1km squares containing 10ha of woodland, compared to 35% in 2003. The British population estimate fell by 29% between 2003 and 2013. The Atlas suggests that presence at the 10x10km scale has declined by 56% between 1970 and 2010. Both data sources suggest regional variation in the rate of decline, with losses greatest in the West and South.Conclusion The Woodcock's population size and breeding range appear to be declining severely across Britain. Regional variation in the rate of decline might be explained by the distribution of large continuous woodlands.