Key points
- The 2023 GWCT/BTO British Woodcock Survey showed the highest coverage to date, with the woodcock population at its lowest level, mainly due to significant losses in northern Scotland.
- Northern Scotland saw the biggest declines, while northern England experienced population growth, and populations in southern Scotland, England, and Northern Ireland remained relatively stable.
- Annual counts showed a similar decline.
- Appropriate woodland management can also encourage open woodland glades and new growth of young trees, creating better conditions for woodcock.
- The number of woodcock shot has declined since the late 2000s, mainly in England and Wales, while hunting levels in Scotland have remained stable.
Background
Woodcock are migratory birds, but there are some resident populations in temperate countries in western Europe, such as Britain, Ireland, France, Spain, Germany and Switzerland. The resident population in Britain has been declining since at least the end of the 1960s. Their range has also shrunk by 56%, between 1962-72 and 2007-2011. This caused them to be added to the Red List of UK Birds of Conservation Concern in 2015.
Well-camouflaged and nocturnal, these woodland wading birds are not easy to spot during standard daytime bird surveys. On a European or global scale, estimating the size of their populations is made even more difficult by the vast and remote location of some of the forests they breed in. Therefore, global assessments of the species’ status, have to combine smaller national estimates which are more reliable. Having estimates of the woodcock’s population size and status is important, as woodcock are hunted in many European countries so we need to understand if and how their populations are changing.
Although woodcock spend most of the day hidden in dense forest undergrowth, their unique breeding display makes them easier to count. At dawn and dusk, males perform ‘roding’ flights to attract females, flying in looping circuits that can cover several hundred hectares of woodland. They look for females waiting in clearings below, but this behaviour also helps surveyors spot them. The results of these surveys allow scientists to estimate the number of birds displaying at each site.
The Breeding Woodcock Survey (BWS) is a GWCT and British Trust for Ornithology (BTO) collaboration, launched in 2003 to estimate the size of the resident breeding populations in the UK and better understand declines. The number of male woodcocks estimated in Britain in 2003 was 78,346. When this was repeated in 2013, estimates indicated a decline in the population of 29.5%.
What they did
The BWS involves a large-scale national survey of woodcock completed every ten years, so far in 2003, 2013 and 2023. Since the scheme was created this has been supported by smaller annual surveys, which saw a boost in participation after 2013. To complete a survey, participants selected a 1km grid square from a random list. They visited it up to three times and spent 75 minutes counting displaying woodcock. Surveys started 15 minutes before sunset and were not taken in bad weather. Selected squares had to contain at least 10 hectares of woodland and be at least 3km apart.
In 2023, over 1,200 grid squares were visited by BWS participants and sites in Northern Ireland were included for the first time, meaning woodcock populations could be assessed there. Squares previously surveyed in BWS 2003 and 2013 were prioritised so we could assess local changes in woodcock numbers.
Surveys squares were grouped into 11 regions in Britain, with Northern Ireland added as a 12th region in 2023. The squares were also assigned to one of four categories based on the amount of woodland they contained. These groupings allowed both region and ‘woodedness’ to be factored into estimates of population size and change.
What they found
Overall, the 2023 BWS had the highest coverage and involvement to date. The British woodcock population estimate was the lowest from previous BWS surveys, showing an overall population decline.
This decrease was almost entirely due to significant losses in northern Scotland, which outweighed the small gains since 2013 across most of England and southern Scotland. In Northern Ireland, woodcock were present but at lower levels than in Britain. Northern England was the only region which saw woodcock populations increase in size since 2003.
Annual counts showed similar trends to the BWS, but with more variation. Between 2003 and 2013, annual counts indicated a decline in woodcock populations that was less severe than BWS data suggested. However, from 2013 to 2023, annual counts showed a slightly steeper decline compared to BWS results. Since the BWS covers randomly selected sites, it likely provides the most representative indication of change. In contrast, annual counts are conducted at a subsample of sites based on continued surveyor participation, which may bias results toward occupied sites.
What does this mean?
Woodcock populations are declining, most likely due to changes in woodland management. Not all woodlands offer the same habitat value. Woodcock, similar to nightingales and marsh tits, need open woodland with young trees. Commercial conifer plantations have significantly altered Britain’s woodlands, but these fast-growing trees are only suitable for breeding woodcock in their first 20 years. As a result, woodcock populations likely respond to the shifting average age of forestry. The best solution is diverse woodland with a mixture of tree species and ages. Appropriate management can also encourage open woodland glades and new growth of young trees, creating better conditions for woodcock.
The BWS surveys data is collected during summer, when only resident woodcock are present. However, hunting during the winter may also be a factor impacting these resident populations. Around 140,000 woodcock are shot in the UK each year, with 91% being migratory birds from Europe and 9% being resident birds. The number of woodcock shot has declined since the late 2000s, mainly in England and Wales, while hunting levels in Scotland have remained stable. This could be due to conservation campaigns or fewer migratory birds reaching southern regions.
Survey promotion has improved, with 50% more surveys in 2023 than in previous years, leading to a better understanding of woodcock populations. Although most woodcock nests are in woodlands, around 14.5% are found in open habitats such as moorlands and grasslands, especially in northern England and Scotland. Survey methods likely capture some of these non-woodland populations, but breeding in areas with less than 10ha of woodland may be underestimated.
Despite some limitations, the trends seen in the data are likely to be accurate. Future improvements include encouraging volunteers to revisit zero-count sites to improve data accuracy and expanding surveys into newly afforested areas. Refining methods for mixed habitats will also help track woodcock population trends more effectively over time.
Our resident woodcock population relies entirely on the condition of our countryside and how we manage it. Continuing to improve our knowledge of woodcock populations and their requirements is essential to make informed decisions and help resident bird populations recover.
Read the original abstract
Heward, C. J., Conway, G. J., Hoodless, A. N., Norfolk, D., & Aebischer, N. J. (2024). Population and distribution change of Eurasian Woodcocks Scolopax rusticola breeding in the UK: results of the 2023 Breeding Woodcock Survey. Bird Study, 71(2), 109–123.