It's hard right now for me to flip stones and logs and not find a Lasius queen. These are usually the social parasitic forms that gather in abundance. Their nuptial flight was last fall. Amazingly they over winter on the surface. The ones pictured above are Lasius claviger, I believe from the abundance of hair. Lasius umbratus queens don't tend to be as hairy.
You can see here I've easily found a few dozen. When the weather warms up they'll venture off separately in search of a host colony, in this case L. neoniger or L. alienus.