Extensive monitoring of Rock Ptarmigan Lagopus mutus in Scotland: a pilot to test the efficacy of using volunteer surveyors for monitoring arctic-alpine birds

Calladine J., Wernham C.

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A pilot study to examine the effcacy of using volunteers for the extensive monitoring of Rock Ptarmigan Lagopus mutus in Scotland attracted 140 volunteer surveyors, many of whom were not specialist birdwatchers. A total of 3,212 km of transects (all self-selected by the volunteers) were surveyed for birds and signs of their presence (faecal piles) between April and August 2006. Encounter rates reported by volunteers were low (means of 0.25 birds and 0.34 ‘sites’ per km - ‘sites’ being an encounter rate that included groups of faecal piles) but they did not differ signifcantly from those achieved concurrently by experienced professional ornithologists (means of 0.16 birds and 0.57 ‘sites’ per km) undertaking monthly repeated surveys of transects for calibration purposes. Reports of no birds were made signifcantly less frequently by volunteers (54% of all survey returns) than by professional feldworkers (77% of transects), potentially indicating that a proportion of surveys where no birds were seen were not reported and that the encounter rates reported by volunteers may be artifcially high. The encounter rates of ‘sites’ by volunteers were highest in April and inversely related to the proportions of the transects covered by snow. No such relationships were apparent in their detection rates of birds, nor for either birds or ‘sites’ in the systematically repeated transect surveys. The differences between the volunteer surveys and the repeated transects are likely to be the result of biases associated with both surveyors and birds selecting snow-free patches. This project indicated interest and enthusiasm by volunteers to participate in the monitoring of Rock Ptarmigan in the mountains of Scotland. For the development of a long-term extensive monitoring programme, issues of reporting nil returns and an enhanced systematic approach to surveying should be explored. Any modifcations of the survey methods need to be acceptable to the volunteers to retain their enthusiasm however.