Wider Countryside Butterfly Scheme (WCBS)

Quality Control

Confidence in the data is good. Automatic rules are used to classify some records as ‘assumed correct’; other records are reviewed by expert verifiers.

Method steps

1. The In the WCBS, BC recorders are allocated randomly selected 1km squares within the county in which they live, whilst BTO recorders are given the opportunity to survey their existing Breeding Bird Survey squares. Both sets of surveyors are asked to survey these squares at least twice over the July and August period with visits spaced ten days apart. Optional visits are encouraged, especially in the spring to sample Orange-tip and for the first generation of bivoltine species. On each visit, recorders survey two parallel 1km survey lines evenly spaced ca300m apart. Along the survey lines, recorders count butterflies, day-flying moths and dragonflies using the same time of day, recording width and weather condition criteria used in transect monitoring. Due to the low level of sampling effort (and unlike conventional transects), WCBS data is not used to derive local measures of butterfly abundance.

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