Update on breeding woodcock abundance

The Eurasian woodcock breeds widely throughout Britain, with notable absences only on the highest ground in parts of Scotland, and in south-west England and south Wales. However, the species is currently ‘amber-listed’ as a bird of conservation concern because of an apparent long-term decline in breeding numbers (-76%, 1974-1999) and range (-31% 1968/72-1988/91).

Until recently, there has been little information on the species’ population size and an estimate of 5 000-12 500 ‘pairs’ was based upon sightings of woodcock made during the course of general bird surveys rather than counts from dedicated surveys. Owing to its cryptic plumage, secretive behaviour and nocturnal habits, the woodcock is a difficult species to survey and it seems likely that the presence of breeding woodcock in many woods may remain unnoticed during general surveys. Hence there was uncertainty about the reliability of these data and the true status of the species.

Knowledge of the status of the woodcock as a breeding species in Britain and Ireland and of any need for conservation action was hindered by the lack of a specific counting method and monitoring programme. The unique display or ‘roding’ flight performed by males provides the best opportunity to confirm the presence of breeding birds and assess numbers. Counts of passes by roding woodcock at fixed points provide the only feasible method for any large-scale monitoring of breeding woodcock populations, but their interpretation has been hindered by the fact that they represent multiple registrations of an unknown number of males. Our recent work involving recording the calls of individual males, has demonstrated the validity of using registrations of roding woodcock for assessing numbers of males.

Subsequently, together with the British Trust for Ornithology, we undertook the first national survey of breeding woodcock in Britain, with the aim to produce reliable baseline population estimates for England, Scotland and Wales against which future estimates could be compared. Using a dedicated survey method, passes of roding male woodcock were recorded on three evening visits to 807 randomly selected sites, stratified by region and woodland size, by volunteer observers during May-June 2003.

Roding woodcock were present at 35% of 1-km squares containing at least 10 hectares of woodland and the mean density of males in occupied squares was 2.76 ± 0.29 birds/km² (± se). There was significant regional variation in the occurrence and density of roding woodcock. The breeding woodcock population in Britain was estimated at 78,350 males (95% CL 61 720-96 490). Previous estimates of the size of the British breeding woodcock population are far too low, but the species might still have undergone a decline in the last 30 years. We are conducting annual roding counts at about 50 sites and plan to repeat the national survey in 2012, to determine whether or not our woodcock population is currently stable.

If you would like to support our woodcock research please donate to the project.

To read more, see:

Hoodless, A.N., Lang, D., Aebischer, N.J., Fuller, R.J. & Ewald, J. 2009. Densities and population estimates of breeding Eurasian Woodcock Scolopax rusticola in Britain in 2003. Bird Study 56, 15-25.