Glasgow & SW Scotland Butterflies

Glasgow & SW Scotland Branch Website

December 12, 2009

The Glasdrum Butterfly Transect 1992-2009

Filed under: Butterflies — Andrew Masterman @ 5:37 pm

Scottish Natural Heritage have run a butterfly transect at Glasdrum NNR as part of the UK Butterfly Monitoring Scheme (BMS) each year since 1992 except for 1997. The BMS runs from the 1st week of April to the last week of September each year and each week is numbered from 1 to 26. From 1992-2002, the number of weeks surveyed was not high but the number of weekly visits since 2002 has been good (Fig. 1).

Figure 1   Number of weeks surveyed each year 1992-2009

Figure 1 Number of weeks surveyed each year 1992-2009

The path of the transect which is shown in the map below runs westwards along the wayleave at the bottom of the reserve and then runs eastwards and up the hillside through a series of large woodland glades before returning to the wayleave via the footpath.
There are important populations of three UK BAP butterfly species surveyed at Glasdrum and a further 20 butterfly species have been recorded over the years.
The first is Chequered Skipper which occurs in large numbers along the wayleave at the bottom of the reserve and is quite common in other parts of the transect too. 2009 was the third best year for this species with a total of 115 being recorded (Figure 2).
Figure 2  Annual Totals of Chequered Skipper

Figure 2 Annual Totals of Chequered Skipper

 

The second important UK BAP species is Pearl-bordered Fritillary which is most common along the wayleave. 2009 was a reasonably good year for this species with a total of 15 (Figure 3).

 

Figure 3  Annual totals of Pearl-bordered Fritillary.

Figure 3 Annual totals of Pearl-bordered Fritillary.

The third important UK BAP butterfly species at Glasdrum is Mountain Ringlet which is monitored by a separate transect at 450 m which has been in operation since 2002 (no data in 2007 owing to poor weather). 2009 was by far the best year on record (Figure 4). On 23 June 2009, a maximum weekly count of 53 was obtained during warm sunny weather and shows how numerous mountain ringlet can be when the weather is warm.
Figure 4  Maximum weekly counts of Mountain Ringlet

Figure 4 Maximum weekly counts of Mountain Ringlet

The other butterfly species which occur at Glasdrum are presented below in decreasing order of abundance.

Scotch Argus is the most numerous butterfly species despite having a relatively short flight period from mid-July to late September. This is a stunning butterfly when newly emerged but most individuals tend to look very worn and tatty by late August. The highest annual total was 1579 back in 1995 and 516 were seen in 2009 (Figure 5).

Figure 5  Annual totals of Scotch Argus

Figure 5 Annual totals of Scotch Argus

 The Small Pearl-bordered Fritillary is the second most numerous butterfly at Glasdrum and also has quite a short flight period occurring from mid-May to early July. The highest total of 433 occurred in 2005 and 146 were seen in 2009 (Figure 6).

Figure 6  Annual totals of Small Pearl-bordered Fritillary

Figure 6 Annual totals of Small Pearl-bordered Fritillary

The Speckled Wood is butterfly which has 2 or 3 generations at Glasdrum being found from late April  to September which results in high annual totals. The highest total was 239 in 2003 and 155 were seen in 2009 making it the third highest year (Figure 7).

Figure 7  Annual totals of Speckled Wood

Figure 7 Annual totals of Speckled Wood

The Green-veined White can be found along the Glasdrum transect in all sections from April to September as it is double-brooded. The maximum count was 84 in 2004 and 2009 had the third highest total with 53 (Figure 8).
Figure 8  Annual totals of Green-veined White

Figure 8 Annual totals of Green-veined White

 

The Peacock is the commonest butterfly along the transect in April and early May and a second generation occurs during August and September. Figure 9 shows annual counts of Peacock along the transect and there were no records prior to 1998. There are two factors here. One is that April visits were not made during the early years of the transect and the second which is more influential is that the Peacock was quite rare in Argyll prior to 2000 but has become much more common since then. The 46 Peacock in 2009 is the fourth highest total.

Figure 9  Annual totals of Peacock

Figure 9 Annual totals of Peacock

The Small Heath occurs at Glasdrum during May to July and the peak year was in 1998 with 67.  While numbers from 2004 to 2008 were quite high, the Small Heath population at Glasdrum crashed in 2009 for some reason (Figure 10).

Figure 10  Annual totals of Small Heath

Figure 10 Annual totals of Small Heath

Meadow Brown is found in low numbers along the transect in mid-summer. The largest number of Meadow Brown were found in 1992 and the 12 recorded in 2009 was the sixth highest on record (Figure 11).

Figure 11  Annual totals of Meadow Brown

Figure 11 Annual totals of Meadow Brown

 

Dark Green Fritillary is found in small numbers along the Glasdrum transect during mid-summer. The highest total of 26 occurred in 1995 and 2009 with 10 was joint 8th highest (Figure 12).

Figure 12   Annual totals of Dark Green Fritillary

Figure 12 Annual totals of Dark Green Fritillary

The Green Hairstreak is found in low numbers at Glasdrum in May and early June but in 1995, a much higher total of 29 was found (Figure 13). None was seen in 2008 or 2009.
Figure 13  Annual totals of Green Hairstreak

Figure 13 Annual totals of Green Hairstreak

 

Orange Tip is a harbinger of spring at Glasdrum as well as other parts of the branch area but only occurs in small numbers. As it is a species of more open countryside and roadsides, only the odd one or two manage to get into the woodland glades at Glasdrum.  Also, the Orange Tip is a butterfly that is responding to climate warming and expanding northwards in Scotland and this trend is evident in the numbers since 1992 along the Glasdrum transect (Figure 14).

Figure 14  Annual totals of Orange Tip

Figure 14 Annual totals of Orange Tip

 

A further five species have only occurred in a proportion of the years 1992-2009 and are shown in Figure 15. Small White has only been since in three years and has not been seen since 2000. Common Blue has been seen in eight years and in every year since 2003. The migrant, Red Admiral has been seen in seven years scattered across the 1992-2009 period and four were seen in 2009. Painted Lady has been seen in eight years and 2009 has of course been a good year for this migrant. Despite this, the 2009 total of just five is the second largest on record as 13 were recorded in 2004. Small Copper has been seen in every year since 2003. Small Tortoiseshell has only been seen twice along the transect, one in 1992 and another singleton in 2007. Marsh Fritillary has been seen just once in 1992 when two were spotted. And just one Grayling has been spotted at Glasdrum in 2007.

 

Figure 15  Annual totals of scarce species

Figure 15 Annual totals of scarce species

Written by committee member, Andrew Masterman

No related posts.

6 Comments »

  1. Great article Andrew. Would be great to see more of these for other transect sites. Do you have a map showing the transect route? I can’t seem to see it on the UKBMS website describing the transect.

    I note that no green hairstreaks were seen on the transect route in 2008/2009. I saw 10 green hairstreak on the upper slopes (~NM997 459) in May 2008, so hopefully it won’t be too long before they recolonise areas that the transect passes through

    Comment by Scott Shanks — December 13, 2009 @ 5:30 pm

  2. Hi Scott,

    Map showing path of transect now added.

    Comment by admin — December 14, 2009 @ 6:51 pm

  3. Hi Andrew
    Quite an effort, I’m a bit surprised the PBF numbers were so low. I must have been lucky on my visits. Or perhaps I stick to lower altitudes and warmer days
    Yours
    JB
    PS Do you want better CS and GH pictures ?

    Comment by Jim Black — January 6, 2010 @ 5:49 pm

  4. Hi Jim,

    I am very proud of my CS mating photograph! What is wrong with it? But thanks for the offer.

    Comment by Andrew Masterman — January 17, 2010 @ 11:38 am

  5. A number of people really enjoy wildlife. Domestic pets of most levels can become your own personal interest. You could possibly delight in watching gulls. If you have had issues finding all of them during the foliage to look at, it could be you want to acquire a associated with canaries, a budgie, or possibly a cockatiel. People that have a home in the nation at times become interested in boosting ornamental chickens, pigeons, or pheasants. Additionally it is helpful to take your mother pet care for your nest about young girls. You may actually raise various prize champions!

    Comment by patrick kane blackhawks jersey — November 6, 2016 @ 2:06 am

  6. With that in mind, listed here are six burning things with M. A new. instruction camp just around the corner.

    Comment by chicago blackhawks sweater — November 6, 2016 @ 12:12 pm

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress