Glasgow & SW Scotland Butterflies

Glasgow & SW Scotland Branch Website

February 13, 2011

Welsh Clearwing Surveys at Loch Rannoch 2011

Filed under: Moths — Andrew Masterman @ 3:29 pm

Welsh Clearwing is a spectacular moth which is a wasp-mimic and its UK stronghold is in Wales where it was first found at Llangollen in 1854.

Welsh Clearwing    Credit:  John Knowler

Welsh Clearwing Credit: John Knowler

Welsh Clearwing was first recorded in Scotland in the Rannoch area in 1867. There are scattered populations in Scotland: the Rannoch area; the Trossachs; Perth; and Glens Affric and Moriston.

Distribution of Welsh Clearwing in Scotland

Distribution of Welsh Clearwing in Scotland

Butterfly Conservation commissioned survey work in 2010 on rare moths in the Rannoch area  as part of the Moths Count project funded by the Heritage Lottery Fund and many other partner organisations. The results for Welsh Clearwing are presented below.

The easiest method of detecting Welsh Clearwing is by searching for exit holes on the south facing aspects of birch trunks. These exit holes which are created by the emerging adults can be numerous and may persist for many years. Searches for exit holes and pupal exuviae (the empty pupal cases which can sometimes be found protruding from the exit holes) increased the number of 1 km squares with Welsh Clearwing in the Rannoch area from seven to 16 which includes two new sites (Killichonan & Innerhadden) away from the previously one known site with Welsh Clearwing: Finnart on the south-west side of Loch Rannoch.

 

Three sites around Loch Rannoch where old Welsh Clearwing exit holes were found in 2010.

Three sites around Loch Rannoch where old Welsh Clearwing exit holes were found in 2010.

 

In Wales and Staffordshire, both Silver and Downy Birch are used (Graham, 2007) but in the Rannoch area, while both birch species are present, Welsh Clearwing exit holes were only found on Downy Birch. In the Trossachs too, Welsh Clearwing is only found on Downy Birch.

Aas and Riedmiller (1994) describe the bark of Downy Birch as “Red-brown at first, becoming greyish-white with brown or grey horizontal banding. Sometimes bark stays brownish even in large trees”. Their description of the bark of Silver Birch is “Shiny, reddish brown at first, later turning pinkish or white with pale grey horizontal markings and dark grey scales, with deep fissures and knobbly bumps towards base of tree”.  A Downy birch trunk riddled with Welsh Clearwing exit holes is shown below while Silver Birch trees tend to have larger crevices and are less horizontally banded.

Downy Birch trunk riddled with Welsh Clearwing exit holes.

Downy Birch trunk riddled with Welsh Clearwing exit holes.

Another difference between Silver and Downy Birch is the tree shape with Silver Birch generally being slender and taller up to 30 m high with branches angled sharply upwards and the outer branches curve downwards such that the foliage appears to elegantly cascade downwards. In contrast, Downy Birch are shorter up to 20 m tall with branches either angled upwards or more horizontal and they don’t curve downwards towards the tip giving the tree a much more compact and less attractive profile. However, both Silver and Downy Birch can hybridise with each other producing intermediate forms which are difficult to identify (Aas and Riedmiller,1994).

The two new sites with Welsh Clearwing exit holes present on Downy Birch trunks, Killichonan and Innerhadden, were discovered during nine random examinations of birch trees around Loch Rannoch. At one further site, only Downy Birch trees were found, but at the remaining six sites, only Silver Birch were present indicating that Silver Birch is dominant along large parts of the banks of Loch Rannoch.

Random sites around Loch Rannoch searched for Welsh Clearwing.

Random sites around Loch Rannoch searched for Welsh Clearwing.

 Given these results, it is unlikely that other new Welsh Clearwing sites will be found along the banks of Loch Rannoch but it is possible that Downy Birch may be present higher up the slopes above Loch Rannoch, so venturing away from the roadside might lead to new Welsh Clearwing sites. On the NBN gateway, there are two 10 km squares to the west of Loch Rannoch with historical Welsh Clearwing records (no specific details available) which need to be explored for presence of Downy Birch and Welsh Clearwing: NN35 and NN45.

Nine random sites around Loch Tummel were searched for Downy Birch and Welsh Clearwing but only Silver Birch trees were found so it is unlikely that Welsh Clearwing is present around Loch Tummel.

Raondom sites around Loch Tummel searched for Downy Birch and Welsh Clearwing.

Raondom sites around Loch Tummel searched for Downy Birch and Welsh Clearwing.

The map below shows the distribution of trees with Welsh Clearwing exit holes around Finnart found during survey work in 2010. New exit holes can be identified by their perfectly round shape and size (10 mm in diameter- see photo below) and fresh edges and a presence of a pupal exuvium (see photo below)  is also proof of occupancy by Welsh Clearwing in the current year. But in some of the 1 km squares below, only old exit holes were found which could mean that Welsh Clearwing is no longer present as these exit holes can persist from many years. Click here for a Word Document containing the Finnart map below which you can print out and take into the field.

Distribution of Downy Birch trees with Welsh Clearwing exit Holes at Finnart

Distribution of Downy Birch trees with Welsh Clearwing exit Holes at Finnart

A perfectly round fresh Welsh Clearwing exit hole.

A perfectly round fresh Welsh Clearwing exit hole.

A Welsh Clearwing pupal exuvium at Finnart on 30 June 2010

A Welsh Clearwing pupal exuvium at Finnart on 30 June 2010

Adult Welsh Clearwing are not easy to find (none found in 2010) but a Welsh Clearwing pheromone lure is available which makes finding adult Welsh Clearwing males easy in areas where they are present. This pheromone lure (termed SCO) can be pre-ordered before April from Anglian Lepidoptera Supplies and this is very effective at attracting male adult Welsh Clearwing during the flight period: late June to July.  Use of this pheromone lure is recommended for 2011 searches in those areas where only old exit holes were found in 2010. At Finnart, these are the following 1 km squares: NN5257; NN5455; NN5355: NN5224 and two further squares with birch woodland but which were not searched in 2010 need to be checked as well, NN5225 and NN5125.

A few new exit holes and one pupal exuvium were found at the first new site in 2010: Killichonan NN5556. At the second new site, Innerhadden, only old Welsh Clearwing exit holes were found so use of the pheromone lure is also required in square NN6657. The extent of this new site was not fully explored in 2010 so the 1 km squares either side also need exploring but it is suspected that these other squares only contain Silver Birch trees.  Click here for a Word Document containing the Innerhadden map below which you can print out and take into the field.

Welsh Clearwing exit holes present in Downy Birch at Innerhadden

Welsh Clearwing exit holes present in Downy Birch at Innerhadden

Welsh Clearwing is a rare moth only found locally at a few sites in Scotland (see Scottish Distribution map at the top of the page). However, it may be under-recorded to some extent, so if you visit the Rannoch area to familiarize yourself with the sort of open birch woodland it occupies and the appearance of the exit holes - trees with exit holes are common in areas in which Welsh Clearwing occurs  - you will be able to recognise potential new sites when you are out and about in the Highlands of Scotland.

References

Aas, G and Riedmiller, A. 1994. Trees of Britain and Europe. Collins Nature Guide.

Graham,A.N. 2007. Welsh Clearwing Synanthedon scoliaeformis on Berwyn, Montgomeryshire. CCW Contrct Science Report. Countryside Council for Wales, Bangor.

January 16, 2011

Largest National Insect Study Reveals Major Changes to UK Wildlife

Filed under: Moths — Andrew Masterman @ 11:14 am

A world-leading research project carried out by thousands of volunteers from all over the UK has shed new light on conservation issues.

The newly-published Provisional Atlas of the UK’s Larger Moths contains up-to-date maps showing the distributions of 868 moth species, many of which have never been published before. The maps are based on a staggering 11.3 million moth records and is the culmination of four years work by the National Moth Recording Scheme, led by Butterfly Conservation. The Atlas is the compilation of centuries of citizen science undertaken by members of the public.

Initial findings from the huge data set include a pattern of considerable decline among some common moth species. These species include the Lappet moth, an amazing species that looks like a leaf and has a ‘snout’ that resembles a leaf stalk. This creature used to be common across central and southern England but has retreated to a few strongholds. Another once-widespread moth, the Stout Dart, now appears to be on the brink of extinction.

Scarcer moths have also suffered serious declines, including the Wood Tiger, Broad-bordered Bee Hawk-moth, GoldSwift, Dew Moth, Light Feathered Rustic and Silvery Arches.

Moths make up a substantial portion of the UK’s biodiversity and their caterpillars are a vital part of the food chain for many birds and other wildlife. The Atlas and the database underlying it is a vital new resource to help society make informed decisions about the environment and to enable scientists to investigate the causes of the dramatic changes revealed by the maps.

Interestingly, the new maps also show that some of Britain’s moth populations are heading northwards, almost certainly as a result of climate change. Types of moth previously confined to southern parts of Britain are now being found in the north or even in Scotland. Examples of species moving north include the beautiful Lime Hawk-moth and striking Red Underwing.

At the same time new moths are arriving in Britain from mainland Europe. Since the turn of the century 28 new species have been seen in the UK for the first time. These include the Beautiful Marbled, Patton’s Tiger and Minsmere Crimson Underwing. Some recent arrivals have successfully colonised southern parts of Britain, such as Clancy’s Rustic, Small Ranunculus and Oak Rustic.
Richard Fox, Surveys Manager for Butterfly Conservation, said: “Moths have a lot to tell us. Their declines alert us to deterioration in the environment. Where they are found can also tell us something significant about climate change. This is why the new Atlas is so important. It is a huge step forward in helping to protect Britain’s moths. It’s been a fantastic effort to get to this stage, with thousands of volunteer moth recorders sending in sightings from every county across the UK. A full analysis of the data is now being undertaken to make the most of this vital and internationally-important resource”.
Moth recording is increasing in popularity and you don’t have to be an expert (or go out at night!) to help. You can contact your local county moth recorder with your sightings and these will be added to the database. To buy a copy of The Provisional Atlas of the UK’s Larger Moths or to find details of your county recorder, visit  www.butterfly-conservation.org

November 24, 2010

Red alert for Britain’s butterflies

Filed under: Butterflies — Andrew Masterman @ 4:59 pm

A new Red List of British butterflies outlines 23 species which are already extinct here or whose numbers have dropped to such low levels that they are vulnerable to extinction.

 The High Brown Fritillary is one of two species rated as Critically Endangered. This species has been the fastest declining of all British butterflies seeing numbers drop by 85 per cent over a 10-year period.

The research confirms that butterflies are not only a highly threatened group in Britain but that they are faring worse than dragonflies, birds and plants. Twenty three species – 37 per cent of all our native butterflies – are considered to be regionally extinct or threatened. This compares to 21 per cent of dragonflies, 29 per cent of birds and 20 per cent of plants. A further 11 butterfly species are classified as ‘near threatened’ in the new Red List, leaving fewer than half (45 per cent) of Britain’s butterflies considered to be safe at present.

The figures are the result of a major re-assessment of the state of British butterfly populations using the International Union for Conservation of Nature (IUCN) Red List approach. It is based on data collected by thousands of volunteer recorders coordinated by the charity Butterfly Conservation and the Centre for Ecology and Hydrology. The results are consistent with previous evidence of butterfly trends and confirm that butterflies are a highly threatened group in Britain.

“The new Red List shows that the number of butterflies in need of our help has increased dramatically in the past 10 years,” says Richard Fox from Butterfly Conservation, who is lead author of the study. “We have already seen conservationists bring the Large Blue butterfly back from extinction but there is so much more we need to do to secure the future for our fastest declining species. They are our heritage.”

The new Red List of British butterflies was produced by scientists working for Butterfly Conservation, the Joint Nature Conservation Committee and the Centre for Ecology and Hydrology.

 

 

Threatened British butterflies defined by the new Red List (in order of threat category and then taxonomic order).

 

 Species

Overall assessment

Black-veined White

Aporia crataegi

Regionally Extinct

Large Copper

Lycaena dispar

Regionally Extinct

Mazarine Blue

Polyommatus semi-argus

Regionally Extinct

Large Tortoiseshell

Nymphalis polychloros

Regionally Extinct

Large Blue

Glaucopsyche arion

Critically Endangered

High Brown Fritillary

Argynnis adippe

Critically Endangered

Chequered Skipper

Carterocephalus palaemon

Endangered

Wood White

Leptidea sinapis

Endangered

White-letter Hairstreak

Satyrium w-album

Endangered

Black Hairstreak

Satyrium pruni

Endangered

Duke of Burgundy

Hamearis lucina

Endangered

Pearl-bordered Fritillary

Boloria euphrosyne

Endangered

Glanville Fritillary

Melitaea cinxia

Endangered

Heath Fritillary

Melitaea athalia

Endangered

Dingy Skipper

Erynnis tages

Vulnerable

Grizzled Skipper

Pyrgus malvae

Vulnerable

Brown Hairstreak

Thecla betulae

Vulnerable

Silver-studded Blue

Plebeius argus

Vulnerable

Northern Brown Argus

Plebeius artaxerxes

Vulnerable

White Admiral

Limenitis camilla

Vulnerable

Marsh Fritillary

Euphydryas aurinia

Vulnerable

Grayling

Hipparchia semele

Vulnerable

Large Heath

Coenonympha tullia

Vulnerable

 

Butterfly Conservation. Company limited by guarantee, registered in England (2206468).

Registered Office: Manor Yard, East Lulworth, Wareham, Dorset, BH20 5QP.

Charity registered in England & Wales (254937) and in Scotland (SCO39268)

 

 

November 2, 2010

Report on Members’ Day at Battleby 30 Oct 2010

Filed under: Events — Andrew Masterman @ 6:37 pm

120 members of the wildlife charity, Butterfly Conservation enjoyed a very successful Members’ Day at the Battleby Conference Centre on Saturday 30 October. A presentation was made to Mr Duncan Davidson as Outstanding Volunteer of the Year, and the audience warmly congratulated Mr Roy Leverton, who was given a Lifetime Achievement Award in recognition of his many years devoted to the recording and study of moths and butterflies.

The event also celebrated the significant milestone of 1000 individual members in Scotland, with a presentation to Mr Tom Delaney of Lasswade, the 1000 th member.Mr Maurice Avent, Chairman of Butterfly Conservation presented the awards saying: “I am thrilled by the enormous enthusiasm shown for butterflies and moths in Scotland, reflected in some of our fastest membership growth in the UK”.

Participants came from all over Scotland, from Thurso to Peebles, and Lochalsh to Kirkcudbright, to compare notes on the butterfly and moth highlights of the year, and to learn how climate change is affecting their distribution. There was also a talk about the culmination of the hugely successful Moths Count project, which for the first time will produce maps of all the UK’s moths.

The day was even rounded off by a ghost story, a fascinating talk by Mr Nick Picozzi on the behaviour of the Ghost Moth, whose males form mating groups or ‘leks’ akin to capercaillie and black grouse, from which the females choose a mate.

Those attending were also able to go to workshops on digital photography, rearing caterpillars at home, and an introduction to the bizarre world of micro-moths.

The star attraction of the day however was probably the spooky Death’s Head Hawk-moth, which had been caught a few days earlier on a North Sea oil rig!

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