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Posted by Jes

Lullybeg/Crabtree Reserve Report

The Lullybeg transect was walked from April to the end of September and the results have been forwarded to the National Biodiversity Data Centre. The figures outside brackets refer to all butterflies counted on the site while figures inside the brackets are transect counts.

A total of 1,240 adult butterflies were counted during a total of 25 visits.
[695 in 25 visits in 2011 and 1,053 in 20 visits in 2010].

Species 2011 2012
Dingy Skipper 17[11] 31[28]
Green-veined White 49[45] 41[26]
Orange-tip 45[41] 11[11]
Large White 1[0] 1[1]
Small White 4[2] 4[2]
Cryptic Wood White 0[0] 1[2]
Brimstone 14[5] 36[14]
Common Blue 81[74] 68[61]
Small Copper 18[17] 23[10]
Red Admiral 26[5] 8[1]
Painted Lady 0[0] 0[1]
Small Tortoiseshell 58[26] 315[140]
Peacock 22[13] 168[53]
Silver-washed Fritillary 1[1] 4[0]
Marsh Fritillary 15[9] 19[8]
Ringlet 185[125] 154[104]
Wall 1[1] 1[1]
Speckled Wood 7[3] 49[4]
Meadow Brown 62[48] 180[126]
Small Heath 88[70] 122[100]
Large Heath 1[1] 0[1]

The Green-veined White, Orange-tip, Common Blue, Red Admiral, Ringlet show declines in 2012 from the 2011 figures while the Large and Small Whites, Wall and Large Heath were the same for both years. All the other species showed increases that were spectacular in the Small Tortoiseshell, Peacock and Meadow Brown. The Small Heath showed an impressive increase. To what might the changes be attributed?
The average temperature for the transect walks in 2011 was 15.64 degrees Celsius, while 16.40 degrees Celsius was the average for the transect walks in 2012. This improvement in the temperatures may play a role, as might other factors beyond our control such as parasite/host cycles. The year 2011 was especially cold during May, June and July at the peak of the season for many species while 2012 did not see the prolonged cool conditions of 2011. In 2012 the months May to July inclusive saw better conditions, but the weather were still far from ideal, with heavy rain occurring, but with an improvement to drier conditions from 8th August. The management work carried out during the autumn of 2011 and the spring of 2012 may have helped to improve the conditions for some species. There is some evidence that this occurred; a Dingy Skipper was observed laying on Bird’s-foot-trefoil growing on an area cleared of dense birch scrub during the autumn of 2011. A female Silver-washed Fritillary was seen examining a ride containing violets [the foodplant for its caterpillars] that was cleared of shading scrub during February 2012; the work was carried out specifically with both butterflies’ requirements in mind. The site remains in excellent condition for most species and it is especially pleasing to report that three of the butterflies that have a threat category assigned to them under the IUCN criteria showed increases [Dingy Skipper, Marsh Fritillary and Small Heath], while the other two threatened species found on the site during 2012 [Large Heath and Wall] were found in the same number.

However the Marsh Fritillary remains a major concern. Despite the increase in the number of adults seen in 2012, only two larval nests were found during the autumn, down from five found in the autumn of 2011. The decline is reflected nationally; in 2010 over 60 larval webs [nests] were counted at Fahee North in the Burren but only six were found there in the autumn of 2012. Surveys commissioned by National Parks and Wildlife Service and carried out in 2012 also found very low numbers on excellent habitats. Clearly the poor weather in late May and in June 2012 played a part as did the very poor conditions during the previous summer. In the meantime we have identified an area of the site with suitable but heavily encroached grassland which we plan to clear this spring. This area will be monitored to see if the butterflies move in to avail of the newly available habitat.

That the reserve is in excellent condition is thanks to the efforts of our members, helpers from the Kildare Branch of BirdWatch Ireland and our partners Bord na Móna who enable our conservation work to continue and for their assistance especially Eamon Mulhall who assisted with the machine work we needed and Catherine Farrell, who liaises closely with Butterfly Conservation Ireland.