Mid-season milestone brings a butterfly bonanza

The high temperatures of the previous week had slackened off to a much more comfortably sunny 23 degrees, giving GH and BG a pleasant walk around on Monday morning. We’re now at the halfway point of the 26-week transect season and butterfly numbers are approaching their high-summer peak. 
This week’s count of 486 was the highest of this year and will probably be exceeded over the coming few weeks, depending on weather conditions.  It’s still the Marbled Whites and Meadow Browns plus a surge in the numbers of Ringlets that are responsible for the high count, but whereas at this time of year we normally record around 14 species, on this transect we counted an exceptional 18. Furthermore … new arrivals included the season’s first Purple Hairstreaks and a Gatekeeper. In short, our list of butterfly species showed a much wider range than normal.

Count details:
204 Marbled White
161 Meadow Brown
45 Ringlet
33 Small/Essex Skipper
​(including 1 confirmed Small Skipper)
8 Large White
6 Small Heath
4 Small Copper
3 Brimstone
3 Dark Green Fritillary
3 Red Admiral
3 Small White
3 Speckled Wood
2 Comma
2 Painted Lady
2 Purple Hairstreak
2 Silver-washed Fritillary
1 Gatekeeper
1 Holly Blue
Count summary:
486 butterflies from 18 species.

Butterflies of the week

Ringlet (Aphantopus hyperantus) – the butterfly with a circle of secrets. (Pictured at top of page.)

• The row of eye-spots (or ‘ringlets') on its wings helps confuse predators, making it harder for birds to target the butterfly's body.
• Unlike many butterflies, Ringlets are happy to fly in dull, overcast weather and shady woodland rides, often remaining active when other species have disappeared.
• Their caterpillars feed on a variety of fine grasses, allowing this species to thrive in meadows, woodland edges and rough grassland across much of the UK.
• When to see them in the UK: Typically June–August, with peak numbers usually occurring in July.

Purple Hairstreak, Hill Wood Field - Brian Gardner

Purple Hairstreak (Favonius quercus) – the hidden jewel of the oak treetops.

• One of Britain's most overlooked butterflies, it spends almost its entire adult life high in the canopy of oak trees, so it's often present but rarely seen.
• The dazzling purple sheen is found only on the upper wings of the male – females are mostly brown with just a hint of purple.
• Its caterpillars feed exclusively on oak leaves, making healthy oak woodland and hedgerows essential for this species.
• When to see them in the UK: Typically July – August, with adults most active on warm, sunny afternoons around mature oak trees.

In bloom now ...

Common Centaury, Fames Rough - Brian Gardner

If you would like to know more about any of the butterfly species mentioned, visit 
​butterfly-conservation.org

This week's survey by  Brian Gardner and Graham Harris submitted to 
​Butterfly Conservation (UKBMS).
​Report by GK, BG & AI.