Arriving at the Glasdrum car park on Saturday 30 May at 8am, I was delighted to find four people already waiting to see the moth catches from light traps set the night before. Twenty four species of moth were caught with the highlight being a Saxon and some very attractive moths were caught including Peach Blossom, White Ermine & Buff Tip.
As we all gathered in the car park for the talk on Chequered Skipper, Pearl-bordered Fritillary and recording butterflies with GPS, a mating pair of Chequered Skipper obligingly arrived so we got off to a good start without even leaving the car park.
After the talk, we divided into two groups (one of 7 & one of 6) with the more adventurous team led by me heading up the west side of Glasdrum to an open area at 800-900 ft where I found some Chequered Skippers last year. The second team led by SNH staff, John Halliday and Hazel White followed the path of the butterfly transect along the wayleave and some large glades which gradually gain height as you head east finally ending in a large woodland glade.
The map below (click for larger image) shows the results for Chequered Skipper recorded with GPS. The upper team recorded 56 Chequered Skipper waymarks relating to positions of Chequered Skipper but high up, several Chequered Skipper were seen at some positions so well over a hundred Chequered Skipper were seen during the day. Chequered Skipper were very numerous in a damp area of Purple-moor grass and rushes at 800 ft, particularly at the northern edge where an escarpment provided shelter. Others in lower numbers were seen on steep slopes with bracken but were noticeably more abundant in flushed areas with mineral enrichment where lush Purple-moor grass was found.
The lower team recorded 55 waymarks with many seen along the wayleave where they occur in numbers and lower numbers were seen elsewhere along the butterfly transect. The map below shows that the paths of the two teams overlapped in the big glade on the western side of Glasdrum where both teams saw a number of Chequered Skipper. This is a good nectaring glade with abundant tormentil & bluebell.
Chequered Skippers recorded by the upper and lower groups
Each team had two GPS devices and the second GPS device was used to record the positions of any other butterflies seen. By chance, the Chequered Skipper weekend happened to coincide with the largest butterfly migration in years of Painted Lady and Butterfly Conservation had organised a survey of Painted Lady on Saturday 30 May to record this phenomenon.
The map below (click for larger image) shows the positions of all other butterflies seen including Painted Lady which arrived in Argyll on the Saturday - none were seen the day before. A total of 49 Painted Lady were seen during the walks by the two groups between 10.45 am and 3.30 pm. This was a very interesting butterfly event to have witnessed and although numbers seen were much lower than recorded in the SE of England, Painted Lady did appear to be falling out of the sky in numbers.
Other butteflies seen by the upper and lower groups on 30 May 2009
Some Pearl-bordered Fritillary were still on the wing on the higher slopes and at the eastern end of the big glade surveyed by the lower group but as many Small Pearl-bordered Fritillary were also on the wing, it was difficult to determine exact numbers of Pearl-bordered Fritillary.
On the Sunday, some people headed off to other sites including the north shore of Loch Etive, Ardgour and near Fort William and found more Chequered Skipper. The weather was fantastic on both days ensuring that many butterflies were seen. Some of us also saw Marsh Fritillary and Narrow-bordered Bee Hawk Moth at nearby Appin adding to a great butterfly weekend.