Warton Crag and Arnside Knott

It was a real scorcher today and Warton Crag and Arnside Knott where alive with butterflies. It's impossible to positively identify every fritillary you see, but for every one Dark Green Fritillary we identified at least 20 High Brown. In total we must have seen easily 100 High Browns. Also about 20 Small Pearl Bordered Fritillaries, and countless Northern Brown Argus, Graylings, Meadow Browns, Small Heaths, Common Blues, Speckled Wood, Small Tortoiseshell, Large Skippers and a few whites. The freezing cold winter certainly doesn't seem to have effected these butterflies.


High Brown Fritillary (left) and Dark Green Fritillary (right). The upperwing pattern is very similar and it is almost impossible to tell the two species apart from the upperwing.

High Brown Fritillary (left) and Dark Green Fritillary (right). The underwing pattern is quite different and is diagnostic. To seperate these two species you really need to see the underwing. Note especially the brown spots with white centres towards the rear of the wing which is diagnostic of High Brown, and the extensive area of green on the lower wing of Dark Green.

High Brown Fritillary is a rare and localised butterfly in the UK, whereas Dark Green is much commoner and can occur as far north as northern Scotland, where I have seen them at Loch Sionascaig, Inverpolly.
I find photographing fritillaries quite difficult, but if you can find an area where they are feeding, you can get very close, and in fact they seem almost drunk with nectar and oblivious to your presence.

Small Pearl bordered Fritillary. This is a much smaller butterfly than High Brown or Dark Green and it's main confusion species is the very similar Pearl bordered Fritillary which flies earlier in the year, and has a different underwing pattern.

Northern Brown Argus. This is the northern counterpart of the Brown Argus which does not occur in northern Britain and has a different flight period. The underwing pattern is diagnostic.