Grizzled Skipper (Pyrgus malvae)
© - Nick Greatorex-Davies
The Grizzled Skipper is a very localised and declining butterfly in Britain occuring in discrete colonies in open, sunny but sheltered, unfertilised grassland, woodland rides and glades or abandoned industrial sites, breeding where the vegetation is sparse and there are patches of bare ground. Best sites occur where there is a mosaic of short and long vegetation where the caterpillars feed on rosaceous plants such as Wild Strawberry (Fragaria vesca), Creeping Cinquefoil (Potentilla repens) and bramble (Rubus sp.). (For further details on this species see http://www.butterfly-conservation.org/).
This chart shows the index of abundance (LCI = Log Collated Index) over time. It shows fluctuations in populations from year to year, and is scaled so that the average index over the whole series is equal to 2 (horizontal line). Further details on the analysis of UKBMS data can be found [here]
This chart shows the average number of butterflies seen on transects between April and October across all sites (fitted values from a Generalised Additive Model). The blue line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.
This map shows symbols for the mean abundance at transect sites, with the colour of the symbol reflecting the level of abundance. Means are over all years. Grey background squares are the occupied cells as shown by the Butterflies for the New Millenium over the previous ten year period.
