Butterfly Surveys at Glasdrum NNR in 2008

Glasdrum NNR, Argyll is on the north shore of Loch Creran about 2 miles east of the Creagan Bridge on the road between Oban and Fort William and is considered one of the best butterfly sites in Scotland. Key species are Pearl-bordered Fritillary, Chequered Skipper and Mountain Ringlet which are all UK BAP species and have good populations at Glasdrum NNR.

A UKBMS transect has been in operation at Glasdrum NNR since 2002 and some large totals of some species including Small Pearl-bordered Fritillary and Scotch Argus have been recorded. The graph below shows weekly counts of Pearl-bordered Fritillary at Glasdrum 2002-2008 which are found in small numbers along the transect.

High totals of Chequered Skipper are recorded along the Glasdrum butterfly transect and annual totals 2002 to 2008 are shown below together with the much smaller annual totals of Pearl-bordered Fritillary.

During 2008, committee member, Andrew Masterman used a GPS device to record the position of each Pearl-bordered Fritillary (PBF) and Mountain Ringlet (MR) seen on two different occasions which was very successful in identifying the areas of Glasdrum which have peak populations of these two butterflies. Chequered Skipper (CS) and Small Pearl-bordered Fritillary (SPBF) were also recorded using this method and the charts below show the results. The sixth chart is for Pearl-bordered Fritillary at Creagan Wood which is privately owned land just to the west of Glasdrum NNR.

PBF 13 May 08	PBF 19 May 08	CS 2008
SPBF 7 June 08	MR 23 June & 3 July 08	PBF Creagan Wood 13 May 2008

The map below pools all the data from the above maps and shows that there are large numbers of butterflies above the main treeline at Glasdrum indicating that important butterfly habitat occurs at altitudes of 200-300 m at Glasdrum. These maps do underestimate the numbers of butterflies on the lower slopes as the butterfly transect was not included during these surveys. It is hoped that surveys in 2009 can be arranged to thoroughly survey both the lower and upper slopes at Creagan Wood/Glasdrum to give a more balanced assessments of butterly numbers.

All Butterflies at Glasdrum 2008

KEY: CS - Chequered Skipper; PBF - Pearl-bordered Fritillary; SPBF - Small Pearl-bordered Fritillary; MR - Mountain Ringlet.

To see where Glasdrum NNR is located, photographs of Glasdrum and Creagan Wood, photographs of Pearl-bordered Fritillary & Mountain Ringlet habitat, photographs of Chequered Skipper, Small Pearl-bordered Fritillary and Mountain Ringlet, click here for a Powerpoint presentation (large file).

Written by Andrew Masterman