Mistaken identity

I got a phone call at lunch time from someone who thought they'd seen a silver studded blue on the reserve. I was there in less than ten minutes - no silver studded blues have been recorded here in the last decade - a searched for nearly three hours. In the end we admitted it must have been a common blue as there were plenty around and they are very difficult to distinguish. As a bonus a clouded yellow flew past just as I was leaving.