Mud-puddling, or simply puddling, is a behaviour most conspicuous in butterflies, but occurs in other animals as well, mainly insects; they seek out nutrients in certain moist substances such as rotting plant matter, mud and carrion and they suck up the fluid.

I think these are both the common blue butterfly or European common blue (Polyommatus icarus).

We'll be away for a few days. Enjoy the forthcoming week.