17 July 2015

High Brown Fritillaries at Aish Tor: 7, 8 and 9 July

Visited Aish Tor on Dartmoor a few times over the last few days to look for High Brown Fritillary and other butterflies. Sadly, the High Brown Fritillary has declined in Britain by 90% since the 1970s and extinct over 94% of its former range. Categorised as Critically Endangered by the IUCN (one of only two Critically Endangered butterflies in Britain, the other being Large Blue Glaucopsyche arion), south-west England is now the species stronghold. There is some good news though - last year their numbers increased by more than 180% compared to 2013 - a ten year high.

A walk from Aish Tor to Newbridge and back on the 7th produced at least 8 High Brown Fritillary (including a female egg-laying beneath the bracken), 1 Dark Green Fritillary, 1 Painted Lady, 1 Comma, 2 Brimstone, 1 Red Admiral, 2 Small Heath, several Gatekeeper, lots of Meadow Brown and several Ringlet, and lots of unidentified fly-by fritillaries. A single Greater Butterfly-orchid Platanthera chlorantha still in flower beneath the Bracken at Aish Tor was a nice surprise, and 1 Grey Wagtail on the River Dart and a Yellowhammer were the best birds noted.

A quick visit late afternoon on the 8th found just a single High Brown Fritillary, 1 Dark Green Fritillary and a Red Admiral. A few Stonechat and a Yellowhammer were also noted.

Several hours from dawn on the 9th were best for photography, when there was a short window between the fritillaires emerging from the bracken and becoming too warm to settle for long. Along with several High Browns a Silver-washed Fritillary was also seen. Birds noted on the 9th include 2 Raven, 2-3 Bullfinch and 1m Stonechat.

High Brown Fritilary, Aish Tor, 9 July. A worn individual but a shot of the underwing showing the diagnostic ocelli just inside the
outer margin on of hindwing.

High Brown Fritillary, Aish Tor, 9 July

High Brown Fritillary, Aish Tor, 9 July. Note the missing third dot from the apex on the forewing on this one (compare with above).
Saw a few like this - an aberration perhaps?

Female High Brown Fritillary egg-laying, Aish Tor, 7 July

10 July 2015

Western Bee-fly: 10 July

Spent some time watching Western Bee-flies Bombylius canescens, at Chudleigh Knighton Heath Devon Wildlife Trust reserve today. Found a colony of around five or six that were firing eggs into the nest burrows of their host mining bee species. Not still for a second, these are darn tricky to photograph! All were females as far as I could see (eyes do not meet at the top).

Female Western Bee-fly Bombylius canescens firing eggs into the nest hole of a mining bee by flicking their abdomen downwards,
Chudleigh Knighton Heath, 10 July

A bee-fly's view of the target - a mining bee burrow entrance, Chudleigh Knighton Heath, 10 July

Two or three were often depositing eggs into the same mining bee nest at a time

They periodically collect dust from bare patches of soil with the tip of their abdomen, to coat each egg to give it extra weight to help it
reach it's target

You can clearly see the 'basket' of dust and soil collected on the tip of the abdomen in this shot

They spent very little time resting. Note the dark femora as well as the dark bristles amongst the pale hairs behind the eyes which
help distinguish from the even rarer Heath Bee-fly Bombylius minor.

Western Bee-fly is a very scarce species, mainly restricted to south-west England, south Wales and eastern Ireland. They fly from May to August.