www.ukbutterflies.co.uk

Is this a Northern Brown Argus? If so, it's a new first for me, and on my local patch too (10 minutes walk from home).

Hi David,

Tricky one this for several reasons:

1. The ID is normally fairly easy based on location, since the distribution of Brown Argus and Northern Brown Argus, don't generally overlap. However, Harrogate is right in the "grey area" between the two. The local BC branch may know better!

2. The white spots cannot be taken as a guaranteed indicator of Northern Brown Argus. In the salmacis subspecies (found in England), the spots may well be completely absent. Conversely, Brown Argus sometimes exhibit minor white spots. And so distinguishing between the two species is near impossible from an upperside shot.

3. You don't have any underside shots. The 2 species are more-easily distinguished from below!

So, I'm going to have to sit on the fence on this one, I'm afraid.

Cheers,

- Pete

Its well out of season for the NB Argus now, they were dying off at the end of June in Durham.

Unless of course there is a second generation?

Thanks Pete and Wayne.
Regarding flight times, I checked the details for NBA elsewhere on the site, which suggests they are still on the wing in early August. However, since they are well past their peak I suppose it would be reasonable to expect any that are still around to be worn and tatty.
The butterfly in question looks fresh and tidy, so on balance, I guess the evidence points towards a second brood brown argus. Do you both agree? Either way, it's a first on my home patch and I was chuffed to see it. I'll return at the next opportunity in the hope of finding it (or another) again and getting a photo of the underwing.