Pearl-bordered Fritillary surveys in Loch Lomond and the Trossachs 2010

The Pearl-bordered Fritillary Boloria euphrosyne has been described as the 'lost butterfly' of Loch Lomond and the Trossachs as it used to be known at a few localities but recent observations are few. One of these localities was the north side of Loch Katrine where it had been seen in the 1980s and 1990s. Efforts to find the Pearl-bordered Fritillary at Loch Katrine in 2008 were unsuccessful as were those in Duke's Pass in an area with suitable habitat. However, it is possible that some of the many 1 km squares further west along the north side of Loch Katrine may have Pearl-bordered Fritillary. The best way of surveying these would be on a bicycle (these can be hired at Loch Katrine) and then walk up through the woods to open hillside above the trees at 200-300 m where steep dry open hillside with dog violet may provide suitable habitat.

Glen Ogle near Killin was also checked out in May 2008 but weather conditions were not ideal and no Pearl-bordered Fritillary were seen. As Glen Ogle has habitat which looks suitable for Pearl-bordered Fritillary, it is worth another look in 2009. A brief visit to Beinn Narnain was also made in 2008 with no success but dog violet was present so also worth another look. The only site along the west side of Loch Lomond checked out in 2008 was Glen Falloch on two occasions and no Pearl-bordered Fritillary were seen: the sites further south still need to be checked out.

It is probably the case that the chances of finding Pearl-bordered Fritillary along Loch Lomond are not high, so if want to visit sites where you are very likely to see Pearl-bordered Fritillary, choose the Loch Tummel Pearl-bordered Fritillary Network or other Pearl-bordered Fritillary sites in Scotland.

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When to Do

Volunteer surveys should be done during mid to late May 2010. Any individuals seen between 21 May and early June may be either Pearl-bordered or Small Pearl-bordered, hence earlier survey dates are preferred but visits in this period may be undertaken if poor weather or circumstances prevent an earlier visit. These butterflies are easy to spot as both species are bright orange and any seen prior to 21 May are very likely to be Pearl-bordered Fritillary.

Methodology

The relevant OS map for the site you want to survey will be required to do this survey. All these sites are quite close to main roads and therefore do not require a long walk in but these south-facing hillsides are steep so a moderate level of fitness is required to ascend up to 250 m or so. Stout walking boots are recommended.

If you see any Fritillaries, it would be appreciated if you could complete a Pearl-Bordered Fritillary Timed Count Sheet which records some details of habitat characteristics such as abundance of Dog Violet & Bugle as well as numbers of butterflies. And of course, record any other butterflies that you come across.

But if you prefer to send in more limited data by email, then please with basic information including 6 figure OS map reference, date and counts of Fritillaries.

The best way to record butterflies is with a GPS device. There are some relatively inexpensive models available eg Garmin eTrex Venture is £134.10 from Amazon.co.uk and can store the positions of up to 500 butterflies with Waymarks. Data is then downloaded onto a computer using software provided with the GPS device. If you want to learn how to use GPS to record butterflies, then please come along to the Chequered Skipper weekend at Glasdrum on 29 & 30 May 2010.

Saturday/Sunday 29/30 May 2010

Chequered Skipper Weekend

Glasdrum NNR, Loch Creran, Argyll

Learn about Chequered Skipper and how to use GPS to record butterflies plus moth trapping

Training day at Glasdrum on the Saturday when amazing habitat for Chequered Skipper and Pearl-bordered Fritillary at 300-350 m will be visited. It is hoped that on the Sunday, participants may look for Chequered Skipper at other sites in Glen Creran & along the north shore of Loch Etive or further north around Fort William.

Participants may wish to stay in Oban, Glencoe or Fort William depending on where you want to search for Chequered Skipper on the Sunday. There is a Camping & Caravanning Club site near Glasdrum at Barcaldine.

Sites in Loch Lomond and the Trossachs to be surveyed for Pearl-bordered Fritillary

The map below shows the 9 sites requiring visits in May 2009. If you place your mouse over the site name, a little window with the site name will appear and if you click on the site name, a 2 x 2km OS map will appear in a new window.

Site Name	Grid Reference (Click for OS map)	Description
Rubha Mor, West Loch Lomond	NS343998	Bracken hillside above steep road escarpment with crawler lane - park at layby to the south of crawler lane, access via style at south end of layby
Firkin Point, West Loch Lomond	NN331011	South-facing bracken hillside in sw corner of NN3301 - park at Firkin Point
Glen Croe, Ardgarten, West Loch Lomond	NN256043	S facing slopes of The Cobbler in Ardgarten Forest - park at Ardgarten Visitor Centre
Beinn Narnain, West Loch Lomond	NN285053	S facing slopes of Beinn Narnain above forestry plantation - park at Loch Long car park
Inveruglas, West Loch Lomond	NN305092	S facing slopes of Ben Vorlich along track up to Loch Sloy - park at Inveruglas viewpoint
Creag an Arnain, West Loch Lomond	NN324108	South-facing slopes above viaduct just north of Inveruglas. Park at Inveruglas or at rough layby close to viaduct.
Ardvorlich, West Loch Lomond	NN324122	100m little hill with S facing hillside just west of railway.
Ardlui, West Loch Lomond	NN315158	SE facing bracken hillside just north of Ardlui - park beside rd at Ardlui station
Loch Katrine, Trossachs	NN4410	Square NN4610 and further east have been checked but squares NN4410, NN4310 & NN4210 have steep-south facing hillsides and could have suitable habitat.
Glen Ogle, Breadalbane	NN564276	South-west facing bracken hillside to north of road extending eastwards about 1km and narrow band south of road- park at layby on north side of road.

Key:

	not yet assessed as suitable habitat
	identified as suitable habitat in spring 2007