Glasgow & SW Scotland Butterflies

Glasgow & SW Scotland Branch Website

October 7, 2010

There’s no stopping the Comma

Filed under: Butterflies — Andrew Masterman @ 6:05 pm

The Comma butterfly, which went extinct in Scotland in the 1870’s is spreading quickly through the southern half of the country, due to climate change. And if the current rate of spread continues, it should arrive in Inverness by 2017!

The butterfly is moving north at between 12 and 15km/year, and in the last ten years has successfully colonised the Borders, all of the Lothians, Fife and the southern parts of Tayside, with recent sightings reported from Dundee and Pitlochry.

Ragged wing edges distinguish this pretty orange and brown butterfly and make it unmistakeable. This, together with the distinctive white comma-shaped marking on the undersides, mean it is an easy butterfly for the public to record.

The butterfly can be seen in gardens and woodlands from May through to September, as it has two generations a year. Commas pass the winter as hibernating adult butterflies, and it was feared that last year’s exceptionally cold winter might have reduced Comma numbers, but recent sightings have shown that it is well established and thriving.

Paul Kirkland, Director of Butterfly Conservation Scotland said: “The large number of records we are now receiving from the public mean we can accurately track the butterfly’s re-colonisation of Scotland. The first butterflies seen a few years back were probably migrants from Northern England, but we know now that the Comma is once again breeding throughout southern Scotland

The colourful caterpillars were found earlier this year in Bridge of Allan feeding on elm, confirming breeding in the Central Belt. Sightings of adults are still being received, and this late in the year they will be butterflies looking for a sheltered place where they can spend the winter.
 
The Comma hibernates through the winter, along with other butterflies such as the Peacock, but you may still be lucky enough to spot one in the next couple of weeks in your garden or in woodland. The undersides of the Comma’s wings are highly camouflaged, which together with its ‘ragged’ outline help it to resemble a tattered dead leaf. This is important to help keep it safe from predators over the winter.

The northern range margin of the Comma (as defined by the average latitude of the 10 most northerly 10km grid squares with Comma records in each period, method of Hill et al 2002 and Hickling et al 2006) has moved northwards by:

150km in the past 10 years (i.e. between 1995-99 and 2005-2010) (15km per year)
362km in the past 30 years (i.e. between 1970-82 and 2005-2010) (12km per year)

This is a big shift, equivalent to the biggest shifts of other resident insects measured to date e.g. Common Darter dragonfly (13.8km per year, 346km northward shift between 1960-70 and 1985-95) (Hickling et al 2005) and Red-necked Footman moth (15.7km per year, 393 km northward shift between 1960-82 and 1983-2009) (Fox et al 2010). Other species, such as Peacock, Orange-tip and Ringlet have also spread north quickly in recent years.

Comma    Credit: Graham Checkley

Comma Credit: Graham Checkley

 

Contact

Paul Kirkland, Director, Butterfly Conservation Scotland,

pkirkland@butterfly-conservation.org

Tel: 01786 447753 Mobile: 07770 732825

 

Louise Keeling, Senior Publicity Officer, Butterfly Conservation

Phone 01929 406 005 

Email lkeeling@butterfly-conservation.org

 

September 5, 2010

Some more photos of Lepidoptera in 2010

Filed under: Butterflies, Moths — Andrew Masterman @ 6:29 pm

The Common Blue  is one species of UK butterfly which shows marked differences in wing colouration between the sexes and there is also a difference in the appearance of the females between northern and southern Britain. The female upperwings are brown and blue with orange margins and individuals from Scotland typically have a higher proportion of blue colouration than those found in England and Wales and completely brown individuals are rare in Scotland. Below is a female Common Blue from the Rannoch area which is more blue than brown

Common Blue, Rannoch, 17 July 2010

Common Blue, Rannoch, 17 July 2010

 Arguably, the undersides of Common Blue are more beautiful than the upperwings as shown below:

Common Blue underwings, Rannoch, 30 June 2010

Common Blue underwings, Rannoch, 30 June 2010

The Northern Eggar which is found on moorland in northern England, Wales and Scotland is a northern sub-species of the Oak Eggar which is found in southern Britain. As well as some difference in the markings, a notable difference between the sub-species is the length of the life-cycle with Oak Eggars having a one-year life cycle while Northern Eggars have a two year life cycle with it overwintering as a small larva in the first winter and as a pupa in the second winter. The flight period is late May to July in Scotland when it can be seen flying fast on moorland - it is a large dark brown moth! But at the same time as seeing adults in flight, the two year life cycle means that you may encounter fully grown caterpillars at the same time as seeing adults in flight. While the bright green with yellow spots fully grown larvae of the Emperor moth certainly are the king of caterpillars in the UK, the caterpillars of the Northern Eggar come a close second. They are large - up to 8 cm - and brown with a stripy appearance and can be found feeding on heather by day. The photo below was taken in the Rannoch area.

Final instar Northern Eggar caterpillar, Rannoch 16 July 2010

Final instar Northern Eggar caterpillar, Rannoch 16 July 2010

 

While the Meadow Brown is certainly not one of the UK’s most beautiful butterflies, its underwings are perhaps more attractive than its upperwings with a two-tone colouring.

Meadow Brown mating, Glasgow, 26 June 2010

Meadow Brown mating, Glasgow, 26 June 2010

The Small Copper is always a delight to come across with both its upperwings and underwings being a colurful copper colour.

Even with big chunks of wing missing, possibly from a bird attempting to eat it, this Small Copper still manages to look bright and colourful

Small Copper, Glasgow, 14 Aug 2010

Small Copper, Glasgow, 14 Aug 2010

 

The Welsh Clearwing is a red data book species and its UK stronghold is in Wales where it was first found at Llangollen in 1854. It was first recorded in Scotland at Rannoch in 1867 and other sites where it occurs locally in Scotland are the Trossachs, Perth, Sutherland and Glens Affric and Moriston.

It has a two year life-cycle with the larvae feeding on the inner bark of old birch trees. The fully-grown larvae shortly before spinning a cocoon and pupating, bore a tunnel to the bark surface just leaving a thin barrier of bark. This allows the adult moth to emerge from its pupa and escape to the outside world in the following late June and July. This sequence of events leaves a characteristic exit hole 5 mm wide and these are visible for many years.  Just after emergence, the holes are perfectly round and the edges show fresh wood and sometimes,  the remains of the pupae (pupal exuvium) can be seen protruding from the exit hole. More info on Welsh Clearwing will be posted on the blog later in the year but in the meantime, here are a few photos.

Downy Birch tree with Welsh Clearwing exit holes. Rannoch July 2010

Downy Birch tree with Welsh Clearwing exit holes. Rannoch July 2010

 

Fresh-round Welsh Clearwing exit hole 2010

Fresh-round Welsh Clearwing exit hole 2010

 

Welsh Clearwing pupal exuvium protruding from an exit hole

Welsh Clearwing pupal exuvium protruding from an exit hole

 

Written by Andrew Masterman

August 16, 2010

Wider Countryside Butterfly Survey Results for three Breeding Bird Survey Squares

Filed under: Butterflies — Andrew Masterman @ 8:48 pm

The Breeding Bird Survey (BBS)  is the British Trust for Ornithology’s flagship bird survey and has been running since 1994. The BBS is a line-transect survey based on randomly selected 1 km squares. It has been very effective in monitoring UK bird populations and has shown changes over time and regional differences. For example, declines in starling populations have been detected all over the UK whereas willow warblers have declined in England but increased a little in Scotland over the 1994-2009 period.

While the UK Butterfly Monitoring Scheme (UKBMS) has been very effective at monitoring populations trends of both rare and common butterflies, these transects are mostly at sites which are good for butterflies and are therefore biased. To get data on butterflies in the wider countryside, the Wider Countryside Butterfly Survey (WCBS) was rolled out in 2009. And WCBS is based on the BBS transect methodology and used the same random selection of 1 km squares to get an unbiased (in contrast to UKBMS) survey in the wider countryside.

In 2009, there was a dual approach with some 20 random selected 1 km squares being allocated to each Butterfly Conservation branch area and bird recorders who participate in BBS were also invited to re-visit their squares for butterflies in the summer.

This article is about the WCBS results from three BBS squares in 2010 which I survey for birds.

NS5057 is at Springhill just south of Barrhead in Renfrewshire and in terms of birds has the greatest number of species with a peak of 42 species recorded in 2006. The rarer species recorded there include lapwing (in 2006), sedge warbler, dipper, yellowhammer and whitethroat.  

Is it logical to expect the 1 km square with the greatest number of bird species to have the greatest number of butterfly species? As intensive farming is thought to reduce biodiversity in general, then yes, this would be a logical expectation.

NS5057 is quite rural and the land use is unimproved grassland which is grazed by cattle, sheep or horses or allowed to grow and is cut in mid-summer and some other fields don’t appear to be subject to any management. There are also a few areas of woodland.

Butterfly Results for NS5057

Species 26-Jun-10 13-Jul-10 07-Aug-10
Green-veined White 1 0 9
Meadow Brown 39 16 0
Ringlet 10 2 0
Common Blue 3 0 0
Peacock 0 0 1

 

So NS5057 had a total of 81 butterflies of five species recorded over the three visits.

NS4060 is at Howwood near Johnstone, Renfrewshire and is another quite rural 1 km square although in this case there are some barley fields and the first half of the transect runs through three improved pastures which are cut during mid-summer. The second half of the transect is quite varied with some wild grassy areas, unimproved pastures lightly grazed and a area of houses with waste ground. From ornithological point of view, this square has a species which has declined dramatically in recent decades owing to modern farming methods: the Grey Partridge.

Butterfly Results for NS4060

Species 02-Jul-10 22-Jul-10 15-Aug-10
Green-veined White 1 12 2
Meadow Brown 9 4 1
Ringlet 1 1 0
Small Copper 0 0 3
Peacock 0 0 6

So NS4060 had a total of 40 butterflies of five species recorded over the three visits.

The Small Copper below was one of two basking on an area of dried mud at a gate separating two fields. For most of the year, this gate area is a mud bath but in summer, it can dry out to form warm basking areas for Small Copper.  This is one example of how grazing animals can favour butterflies although often it is not just the creation of bare araes for basking but also the creation of disturbed soil which provides suitable ground for the larval foodplant to grow in.

Small Copper at Howwood 15 August 2010

Small Copper at Howwood 15 August 2010

 

NS6153 is the most urban of the three squares and is located at East Kilbride, Lanarkshire although parts of the transect are somewhat rural. Since 2004, there has been a significant land use change in this more rural area with conifer plantations being felled to give way to an area of birch scrub regeneration. This led to Goldcrest disappearing from this area and Whitethroat appearing together with more Willow Warbler.

Butterfly Results for NS6153

Species 03-Jul-10 29-Jul-10 15-Aug-10
Green-veined White 0 15 12
Meadow Brown 1 1 0
Small White 0 2 3
Small Tortoiseshell 0 7 3

So NS6153 had a total of 44 butterflies of four species recorded over the three visits.

Small White was present in this more urban square which is expected as Small White (and Large White) is associated with brassica growing which is more common in areas where people live. The Small Tortoiseshell were found nectaring on flowers along a stream on the transect.

The results show that the two more rural squares, NS5057 and NS4060,  had a greater number of species, five, compared with the more urban square, NS6153, four. In terms of total butterfly numbers, NS5057 had the greatest number of 81 while the more urban square, NS6153 unexpectedly came second with 44.

As someone who is intimate with these squares so to speak as a result of bird surveying in them twice a year, I was surprised by how many butterflies were present. This was particularly true of the urban square, NS6153, at East Kilbride which I expected to be a wasted effort.

It is possible that Meadow Brown and Ringlet were more numerous this year, especially in NS5057,  as the cold winter followed by the dry spring delayed grass growth significantly. The first visit occurred when many of the grass fields had not been cut and in most years, a cut may well have been made by late June/early July. Far fewer Meadow Brown were encountered during the second visit when some of the fields had been cut.

Overall, this exercise has been very successful in detecting common butterfly species in the wider countryside: green-veined white; meadow brown; and ringlet. The more interesting species were:

1)  common blue in a field grazed by horses in NS5057 which supported the foodplant, bird’s foot trefoil.  

2) small copper in unimproved pasture at NS4060 on bare ground created by livestock at a gate.

Written by Andrew Masterman

August 14, 2010

Have you got any butterflies on your buddleia?

Filed under: Butterflies — Andrew Masterman @ 4:33 pm

Late August and September is the time when large numbers of Peacocks, Red Admiral and Small Tortoiseshell can sometimes be seen on buddleia. But the ones I have seen near where I live in Glasgow’s southside are sadly bare of butterflies.

Peacocks emerge during August and I saw quite a few Small Tortoiseshell in East Kilbride in 29 July so there ought to be some butterflies on buddleias. I have only seen one Red Admiral and one Painted Lady this year so large numbers of these are unlikely to be seen on buddleias this year.

Peacock   Credit: Scott Shanks

Peacock Credit: Scott Shanks

Please report your butterfly sightings on buddleias by adding a comment. If you provide a grid reference, place and date and your name too, the sighting can be recorded as a record by the Branch Recorder, Scott Shanks.

Written by Andrew Masterman

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