Nov 03 2020

Langley Vale Wood – Butterfly Transect – 2020 Highlights

Despite COVID-19 restrictions, a few dedicated wildlife monitors at Langley Vale Wood were able to carry out a transect walk in each of the 26 weeks of the surveying season from 1 April to 30 September.

 

Wildlife Monitor Keith Lelliott shares his highlights of this year’s survey results…

 

This year’s weather patterns were unusual (aren’t they always!); February was extremely wet, followed by warm, dry and sunny days in April, May and early June. This was very good for wildflowers until the lack of rain started to limit growth. June and July were surprisingly windy and the weather variable. This continued into August with extreme heat for a few days in early August and a deluge towards the end of the month. September was reasonably warm and we enjoyed an Indian Summer.

 

The impact of the weather seemed to bring forward the flight period for late Spring/early Summer species by a week or two. The extreme heat in August followed by heavy rain lead to a rapid decline in our meadow species (Meadow Brown, Ringlet, Gatekeeper). The warm September saw a good number of Common Blues and Small Coppers on the wing.

 

Butterfly numbers in 2020 were up significantly as the following comparisons show:

 

2018

2019

2020

Number of surveys

19

23

26

Number of sightings

2,982

3,902

4,933

Average per survey

(% increase)

157

169 (7.6%)

190 (12.4%)

Highest weekly total

(Week)

496

(24 June)

729

(8 July)

728

(1 July)

Number of species

27

29

31

Top 3 species:

(% of Total)

Meadow Brown (36%)

Common Blue (7%)

Small White (7%)

Meadow Brown (32%)

Gatekeeper (11%)

Ringlet (11%)

Meadow Brown (36%)

Brimstone (7%)

Small White (7%)

 

The number of butterfly species sighted has increased each year, with 32 species recorded over the three years. The new species for 2020 was the Dingy Skipper.

 

Most species’ numbers were up in 2020, particularly for the Small Copper, Small Tortoiseshell and Peacock. The Dark Green Fritillary is also becoming more common. But the Painted Lady, a migrant butterfly, was locally and nationally scarce in 2020.

 

Kidney Vetch is the larval food plant for Small Blues. The seeds sown in 2018 flowered this year in the chalk scrapes in both Front o’ Pips and Back o’ Pips, and with germination of new plants we are now set up for annual flowering of this biennial plant. Excitingly, one Small Blue was seen on the Kidney Vetch in the Front o’ Pips scrape this year, possibly laying eggs, with a handful of sightings elsewhere on site.

 

Horseshoe Vetch is the larval food plant for Chalkhill Blues. Seeds sown in 2019 have germinated along the southern edge of both scrapes. This is a perennial flower and takes longer than Kidney Vetch to establish. A few Chalkhill Blues were seen on site, probably flying over from colonies on Epsom Downs, but none were seen in or near the chalk scrapes this year.

 

Grassland management outside of the scrapes is designed to make them more species-rich over time, thus improving the habitat for a number of invertebrates, including butterflies.

 

Text and photos supplied by Keith Lelliott Wildlife Monitor at Langley Vale Wood

 

20 October 2020

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