Glasgow & SW Scotland Butterflies

Although we have yet to receive the first sighting of a Scotch Argus in 2010 on the date of writing this blog post (21 July 2010), the first ones are very likely on the wing now.

While the Scotch Argus can be found in much of highland Scotland and in parts of southern Scotland, the greatest numbers occur in Argyll where for a few weeks from late  July to early September each year, the multitudes of this stunning butterfly are an amazing butterfly spectacle! You can find them everywhere in Argyll: along roadsides; in woodland rides; on hillsides, on coasts etc. Although they are only on the wing for two months of the year (mid-July to mid September), the Scotch Argus is Argyll’s most numerous butterfly.

As the flight period progresses, Scotch Argus become progressively more worn and tatty. To see Scotch Argus at their best, you need to visit Argyll between late July and mid-August on a sunny day although if you want to photograph them, choosing a warm cloudy day is the solution. The following Scotch Argus photos were taken at Bridge of Awe NN033302 on 26 July 2008 when warm but cloudy conditions meant the butterflies were sufficiently inactive to make photographing them possible. This Bridge of Awe meadow is a great butterfly site worth stopping at anytime from May to September as you are guaranteed to see a number of butterfly species on a sunny day.

So a trip to Argyll is strongly recommended between late July to mid August to see Scotch Argus in their prime and in multitudes. Good places to stop and look for Scotch Argus and other butterflies are shown on this spreadsheet which details the results of a voluntary survey I did in Argyll during the lovely warm dry summer of 2006.

Andrew Masterman

In recent years we’ve seen a significant increase in the number of Comma sightings in SW Scotland. Until now these records have all been of adult commas, but thanks to Heather Young of the SW Scotland branch we now have proof of Commas breeding in the branch area.

Comma Caterpillar 13-07-2010

On the 13th of July, Heather found this nearly full grown caterpillar on an elm near Bridge of Allan, Stirlingshire (NS788988). She suspects it was wych elm, but is having the elm species confirmed by a botanist to be sure. The caterpillar began to pupate a few days later.

There have been only 2 other records of comma caterpillars in Scotland in recent times. On both occasions they were in the Borders. The first was seen in 2006 at Sprouston near Kelso, on elm, and the second at Duns in early July 2010, on nettle.

The Comma caterpillar is quite distinctive, with a large white patch at the rear of the body which gives them the appearance of a bird’s dropping. The mature caterpillar will sit happily on the upper surface of leaves, trusting in their bird-dropping mimicry to keep them safe from predators. In England and Wales comma caterpillars can be found on stinging nettles, elm, wych elm, hops and occasionally currents. The pupa resembles a dried leaf dangling from the food plant and is much harder to find!

If you are out for a walk and pass patches of nettles or a stand of elms in SW Scotland keep an eye out for Comma caterpillars (and adults!) and let us know.

Heather Young & Scott Shanks

Caterpillar photograph (c) Heather Young 2010.

The Pebble Hook-tip is one of six species of moth belonging to the family Drepanidae which occur in the UK. Hook-tip refers to the tips of the forewings which are strongly hooked.

The photo below was taken at Glasdrum on 29 May 2010 during the Chequered Skipper weekend and is of the scotica sub species.

 Pebble Hook -tip

If you are unsure of the difference between the underwings of a Pearl-bordered Fritillary and Small Pearl-bordered Fritillary, compare the next two photos.

Pearl-bordered Fritillary

Small Pearl-bordered Fritillary

The following is the upper-side of the same Pearl-bordered Fritillary.

Pearl-bordered Fritillary

Now for something completely different!

 The Tussock moths of the family Lymantriidae are so-named because of the characteristic tufts of hair on the backs of the caterpillars. The caterpillar of the Dark Tussock is a good example as it has white tufts either side of a black stripe in the middle of the body with yellow tufts at either end!

Dark Tussock caterpillar at Schiehallion 26 May 2010

This second photo of another Dark Tussock caterpillar is quite kitten-ish!

Another Dark Tussock caterpillar near Trinafour, Perthshire 17 may 2010

Talking of hairy caterpillars, the “Woolly Bear” caterpillar of the Garden Tiger must now be mentioned. This amazing caterpillar is presumably a good example of how evolution by natural selection can produce extreme morphology!

“Woolly Bear” caterpillar of the Garden Tiger at Schiehallion 26 May 2010

The Broad-bordered White Underwing is a Red data Book  species found only above about 2000 ft in Scotland although one was recorded on the summit of Cheviot in Northumberland on 12 June 1974. Most Scottish records are from the central Highlands. Twenty five were found near the summit of Meall Breac (802 m) on the south-east side of Loch rannoch on 31 May 2010 and a further three on neighbouring Geal Charn.

Broad-bordered White Underwing on Geal Charn 26 May 2010

An even rarer mountain moth is the Small Dark Yellow Underwing which is classified as Nationally Scarce A.  This mountain moth flies very fast and occurs in low numbers and is very difficult to detect. One was found on the top of Meall Breac, Loch Rannoch after 4 hours searching and another found on Schiehallion after 5 hours searching. A very attractive moth but a real blighter to find!

Small Dark Yellow Underwing Meall Breac 31 May 2010

Another moth of the mountains is the Emperor which is the only UK member of the moth family Saturniidae. The large green caterpillars with pink spots which you can find on heather in August are spectacular but so too are the adults! The photo below is of the larger female - an Emperess? - which is quite mesmerizing.

Female Emperor moth at Schiehallion 19 May 2010

Another moth characteristic of heather moorland is the Common Heath and the males have spectacular feathered antennae. 

Male Common Heath at Schiehallion 30 May 2010

Returning to butterflies, the Green Hairstreak is a butterfly which can be found on heather moorland as its caterpillars feed on Blaeberry.

Green Hairstreak at Trinafour, Perthshire 17 may 2010

Written by Andrew Masterman

We are looking for volunteers to help with a national (UK) survey of butterflies during 2010.

A pilot survey had been run for a few years down south and was rolled out nationally last year. It requires each region in Britain to undertake a survey of up to 25 one kilometre squares two or three times a year during the summer. Last year we only managed to survey one third of our allocated squares and are keen to do better this year. The squares are distributed to each region by a random computer allocation, this is to give the project a scientific robustness. All squares are assessed in exactly the same way so if these squares are surveyed again in the future it will be in the same fashion, even if by a different volunteer.

Often surveys depend on individuals choosing places that are local, convenient or likely to be rewarding for finding butterflies. All good reasons for surveying, but means that other areas not so obviously appealing are overlooked. In order to overcome such a selection bias this survey has been set up to look elsewhere in a region, essentially to see what is out there.

Unfortunately this has meant that in a region like the west of Scotland some of the randomly allocated squares are in areas difficult to access. So our coverage has been less successful than elsewhere. Last year I explored two areas, one mainly a large farm and the other a hill top plantation. Neither on the face of it especially appealing, but the exploration of countryside that I would not normally visit was interesting and educational. I did see plenty of butterflies, although none were unexpected. The sighting of large numbers of Scotch Argus at the edge of the forestry plantation was rewarding. Especially as it was at the end of my final survey of the year.

The volunteers who surveyed last year area keen to examine their squares again this year, but that still leaves several squares unallocated. A minimum of two visits to each site are required, one in July and one in August, at least 10 days apart. A visit to reconnoitre the square before hand is recommended and to plan in detail the path of the survey. The organisers would like to encourage visits in May and June as well, if the volunteer is willing.

Our kilometre squares cover the area from Dumfries and Galloway to as far west as Jura and we would hope that volunteers would take on a survey of a square near to them. The vacant squares are listed at the end of this article, each is defined by OS coordinates, but I have listed approximately where they are and the type of terrain found within the square.

Briefly the survey involves walking across the square and back again in two roughly parallel lines at least 250 metres apart. The exact route will evidently depend on the terrain and access, but it does have to be described clearly and recorded in detail. My experience showed that this is a naive expectation, especially in the West of Scotland. I could have struggled in a straight line through tightly packed trees of the forestry plantation, instead I chose to keep to rides and the few open spaces. This made for a long walk, but with a friend a thermos flask of coffee we took our time and recorded plenty of butterflies. Nothing special, but we added important data to the project. Even in the middle of an extensive conifer forest Green Vein Whites abound, along with many Orange Tips. It will be fascinating to find out how they are doing after such a grim winter.

The other survey was essentially on a cattle farm. The farmer could not have been more helpful, but insisted we keep to field edges and avoid fields with cattle in them. We were happy to oblige! Consequently the trek across this kilometre square was extensive as we zig zagged around his fields, avoided his inquisitive cows and saw plenty of insects. Interestingly the butterflies seemed keen to keep close to the hedges and borders too. We counted large numbers of Green Veined Whites and Orange Tips on the first visit and plenty of Peacocks, Red Admirals, Ringlets and Meadow Browns on later visits. Like elsewhere in the UK at both sites we recorded Painted Ladies.

The method to record butterflies is the same as that used in official butterfly transects. It is really quite easy and involves recording only those butterflies (species and number) that you find or that fly into an imaginary cage 5 metres ahead of you. This ‘cage’ moves forward with you as you walk at a steady pace along the determined pathway. Once again this is very idealistic, as it is better to forget about this imaginary square when dealing with the real problems of crossing a brook, climbing over a rickety gate or avoiding frisky cows.

Butterflies that you see elsewhere are not included in the transect records, but should be separately noted. Hence there are two different recording forms that the volunteer will have to complete. Recorders are also encouraged to note day flying moths and dragon flies as well if you are confident enough to identify them. I certainly saw plenty of day flying moths and have improved my dragon fly identification skills.

There are certain weather conditions that determine when these visits can be made. Basically on a warm, sunny day when there is a minimum of wind blowing. An ideal day for butterflies and, of course, an ideal day for a walk. The exact limits and conditions are described in the detailed documents I can send out to anyone interested in volunteering.

So if you are keen then please let me know. There are plenty of species to record in the West of Scotland, but we need to have a better idea of where they are and their numbers. The data collected on a National basis in a uniform way will be a powerful source of information for Butterfly Conservation and other agencies to use in their discussions with Government (National and Local) on Biodiversity issues.

Please contact me via e mail jo.davis60@btinternet.com .

A useful website about this survey is http://www.ukbms.org/wcbs.htm

The 11 vacant sites are as follows:-click on Map reference link to see OS map of 1 km square in top right corner.

Written by Jo Davis