At the moment I have tons of these in my garden (as well as Hoverflies and wasps).
They are congregating on the plums fallen from my tree. I've been away for the weekend so hadn't been able to clear it all away yet, but I should have it finished tomorrow evening... of course there are still loads of plums on the tree yet to come down, so I still won't be finished :)
BTW - it's on Bronze Fennel.
