The GWCT, in conjunction with the British Trust for Ornithology (BTO), co-ordinates the only national survey of Britain’s resident breeding woodcock population. First conducted in 2003, and repeated in 2013, the survey uses a specially developed methodology that relies upon the male woodcock’s conspicuous roding display.
Surveyors count displaying males, at dusk, across a network of randomly selected woodland sites across the UK. The third iteration of this important national survey will take place in 2023. We cannot conduct a survey of this scale without the help of GWCT and BTO members, and we are encouraging potential volunteers to take part in the 2023 repeat of this important survey.
To see a list of potential survey sites, and to register to survey one near you. please visit:
www.bto.org/woodcock
We use roding count results to produce an estimate of male woodcock density at each survey site. We do this using a calibration equation, developed by the GWCT, that is capable of converting ‘registrations’ (i.e. sightings relating to an unknown number of birds) into an estimated number of males. From these, we can estimate average density for different regions and wood sizes and extrapolate to produce national estimates of population size. With successive surveys, we can also assess population change over time; between 2003 and 2013, the British population estimate dropped by 29%. To ensure our results are as accurate as possible, we try to survey a ‘representative’ sample of wooded squares and it’s important this includes less favourable sites, including those where woodcock are absent.
Getting involved for the first time
Surveyors are required to make two or three dusk counts during May-June. We are particularly keen to enlist surveyors that might be able to count in more remote parts of Scotland, northern England and Northern Ireland where survey coverage is traditionally low. No experience is necessary, but we encourage you to make a recce visit in April to find a suitable count point and get familiar with their distinctive calls. A suitable count point could be a clearing within a woodland, or the intersection of two woodland rides.
Getting involved again
If you have previously surveyed a site, but not since 2019, you will need to visit the website to re-register. Returning observers should note that it is not vital to revisit exactly the same clearing, especially if regrowth of scrub or young trees has reduced its suitability – instead count from the most suitable location within the designated 1km square (or up to 400m from the boundary, if access is difficult). A recce visit in April may be useful to check the state of past count points and find an alternative if necessary.
Why conduct the survey again?
We know that woodcock declined between the last two national surveys. Annual monitoring at a subsample of sites since 2013 suggests declines have continued, albeit with some stabilisation in recent years. More up-to-date evidence can better inform woodcock conservation and policy. Continued monitoring will capture the woodcock population’s response to ongoing environmental and land-use change, such as the marked increase in tree-planting, which may benefit resident woodcock.
Why are you surveying sites where there are no woodcock?
We know there are sites in our list of proposed survey locations that are unlikely to host breeding woodcock. This list is structured by woodland size and region, but otherwise selected at random. This is so that, when we scale up to national population estimates, we do not over-represent more favourable sites where woodcock are thriving. Instead, good and poor, occupied and unoccupied sites should be represented in roughly the proportions that they occur across the UK.
Why are there no sites near me?
We generate different numbers of potential survey sites for different regions. As a general rule, there are fewer sites available in areas with fewer people. Past experience with similar surveys shows that providing too broad a selection of sites for less populated areas means only those conveniently close to human habitation are covered. This year, however, we intend to release a second batch of survey squares once core sites have been allocated, so please check the site map again during March/April. We are very grateful to volunteer surveyors who commit to surveying more remote sites as these provide the necessary variation to ensure a representative sample.