Common Blue?

[jeremiah]

I've been looking at the Gallery pictures and just can't tell the difference between Common and Silver Studded blues.

There are two individuals here - the one in the fourth picture didn't open its wings.

[GuyF]

These are Common Blues, the first is a male and the second looks like a male too.
Silver-studded Blues are much rarer, being mostly confined to heathlands in the South along with a few other areas. In males, the upperside of Silver-studded Blues tends to have a noticeably thicker black border than in Common Blues, and the ground colour is a darker blue although this might not be especially useful unless you can compare both species side by side. If you can get a good look at the underside, the blue scales in the black spots (which give the Silver-studded Blue its name) are diagnostic.
Guy

[PMG]

Here are two pics of silver studded blues I took recently on the Great Orme in North Wales where there are lots of little colonies of SSB's. I too wondered how I would tell the difference as Common Blues also fly and perch in the same areas. I needn't have worried - the North Wales form of silver studded are tiny in comparison - some were less than half the size of the commons and also a noticeably elongated shape to their wings rather than the nicely chunky rounded shape of the commons.

One of the main differences are the thick black borders on the upper wings of the males - no use I hear you say when they don't open their wings! Ok with wings shut look at the spots on the under side of the upper wing - there are 5 black spots in a crescent and underneath a black crescent shape - after this down the wings connection to the body there are no more spots - its a clean, clear, beige to blue shade!

Hope this helps!

Pauline

[jeremiah]

Thank you both, that's very helpful.

[GuyF]

Originally Posted by PMG

Here are two pics of silver studded blues I took recently on the Great Orme in North Wales where there are lots of little colonies of SSB's. I too wondered how I would tell the difference as Common Blues also fly and perch in the same areas. I needn't have worried - the North Wales form of silver studded are tiny in comparison - some were less than half the size of the commons and also a noticeably elongated shape to their wings rather than the nicely chunky rounded shape of the commons.

One of the main differences are the thick black borders on the upper wings of the males - no use I hear you say when they don't open their wings! Ok with wings shut look at the spots on the under side of the upper wing - there are 5 black spots in a crescent and underneath a black crescent shape - after this down the wings connection to the body there are no more spots - its a clean, clear, beige to blue shade!

Hope this helps!

Pauline

That second one which is almost completely lacking the 'silver-studs' is interesting Pauline, it shows that you can never really rely on a single feature!
I find the orange markings can be quite helpful too although they vary, but in Silver-studded Blues they are often merged and may form a complete band as your underside shot shows, whereas in Common Blue the spots are usually more clearly defined.
Two very nice photos!
Guy

[PMG]

Yes Guy! so much so that I wasn't convinced it was an SSB - the only thing in its favour was its tiny size - I could not believe just how small they are and never having knowingly seen them elsewhere I was mesmorised! We're talking a one-wing span of less than a centimeter and a curious elongated shape. I took pics as hurredly as I could plus my car, even tho tucked in to the side as much as I could, was slowing traffic and the open topped bus driver who had to squeeze past was not amused at all ..... A gale had begun to blow and huge spots of rain were splashing down - we were on the last minute before the good weather broke to lashing down and a very wild wet evening! Its somewhere I must go back to in better weather next year and have another look at these fascinating tiny butterflies ......

Pauline