Small Blue (Cupido minimus)
© - Nick Greatorex-Davies
The Small Blue is a small, very localised and easily overlooked butterfly that occurs in small discrete colonies on herb-rich grassland on calcareous soils where its foodplant Kidney Vetch (Anthyllis vulneraria) grows. It has declined throughout most of its British range. Changes in management are likely to affect the quantity and quality of foodplant available for oviposition and subsequent survival of the larvae. Some disturbance is usually necessary to provide good germination sites for the establishment of new plants of this biennial or short-lived perennial.(For further details on this species see http://www.butterfly-conservation.org/).
Status since 1978 is Stable with a change of 18.0% since monitoring began for this species.
Status over the last 20 years is Stable with a change of 39.8%
Status over the last 10 years is Rapid increase with a change of 97.0%
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 Arpil 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.