Development of a survey method for breeding Woodcock and its application to assessing the status of the British population.

Abstract

In a recent review of the population status of birds in the UK, the Eurasian Woodcock (Scolopax rusticola) was 'amber listed' as a bird of conservation concern because of an apparent long-term decline in breeding numbers and range. However, to date the available data have consisted of incidental sightings of Woodcock during the course of general bird surveys rather than counts of roding males. In 2003 The Game Conservancy Trust and The British Trust for Ornithology undertook a survey of breeding Woodcock with the aim of producing population estimates for England, Scotland and Wales. We present data on seasonal and evening patterns of roding activity which were used to decide upon our survey method. These indicated that in Britain, May and June are the most appropriate months for surveying roding Woodcock and that 83% of Woodcock passes at a fixed point should be detected in a one-hour survey commencing 15 mins. before sunset. Owing to appreciable variation in roding activity between evenings, we used the maximum count of registrations from three visits to each survey location in analyses of the national survey data. The survey showed large regional differences in the occurrence of Woodcock and in numbers of registrations at woods where Woodcock were present. Overall, Woodcock were present at 43% of woods surveyed (n = 900) and the mean number of registrations at these sites was 9.5 0.4 (n = 390). Controlling for the effects of region and woodland density, numbers of registrations were higher in mixed woodland than in conifer woods and were highest in deciduous woods.