Green Hairstreak - Callophrys rubi

Apologies for posting three butterflies in a row. I'll make sure I post something different tomorrow.

I have known for some time that there are colonies of green hairstreaks nearby but mostly did nothing about it. I did find out a general location a couple of years ago but found nothing since it was by then too late in the year.

Today, I remedied that and found at least a dozen of them and even managed a few clear images. Too late for them mating though I saw one ovipositing. I think most of the ones photographed were males, based on their behaviour, but I'm not sure yet how to identify the sexes based on appearance. The amount of white on their underwing was variable. The one I'm blipping had the most.