United Kingdom Butterfly Monitoring Scheme (UKBMS) data

This is a series of datasets available from the UK Butterfly Monitoring Scheme (UKBMS). The UKBMS comprises a suite of surveys carried out each year across the UK that generate data on butterfly abundance.

The UK Butterfly Monitoring Scheme (UKBMS) has operated since 1976 and involves thousands of volunteers collecting data every week throughout the summer. The scheme comprises three survey methods:

1. Traditional butterfly transects (Pollard walks): Butterfly data is recorded from fixed-route walks (transects), typically about 2-4km long, established at a site and recorded on a regular (weekly) basis under reasonable weather conditions for a number of years from the beginning of April until the end of September. Most transects record all butterfly species, some focus on a single species and are just recorded during that species flight period.

2. Wider Countryside Butterfly Survey squares: Butterflies are counted along fixed-route walks, within randomly selected 1km grid squares and recorded at least twice during July and August under reasonable weather conditions, although additional counts may be made during the spring and summer.

3. Other methods: Alternative, more rapid approaches targeted at specific species and sites include ‘timed counts’ (recording the abundance of adults of a particular species over a set period of time and within a set area during suitable weather conditions) and egg and larval web counts (recording the number of eggs or larval webs of a species (e.g. Marsh Fritillary) from a given area of suitable habitat.

UKBMS data is widely used for research; a list of publications as well as downloadable PDF copies of past Annual Reports is made available via the UKBMS website.

Datasets currently available for download include annual site level indices of abundance, UK and country-level collated indices of abundance, UK trends in abundance and phenology data for all commonly occurring UK butterfly species on monitored sites across the UK since 1976, as well as annually updated site location data for all UKBMS sites. Access to other data should be requested directly via the UKBMS website.

The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation, the UK Centre for Ecology & Hydrology, British Trust for Ornithology, and the Joint Nature Conservation Committee. The UKBMS is indebted to all volunteers who contribute data to the scheme.