I find about 1-2 per day in my bathroom and flush them down the toilet. As you can see they're very small, maybe 2mm long. They don't appear to have wings but I have found them on walls and the bathroom net curtain. Only noticed them since we had new carpet and lino, although they may not have been visible against the previous bathroom carpet. I have found only one in another room - the spare bedroom next to the bathroom, on the windowsill. They are usually found on the floor. They all have 4 spots each and long antennae and go very still when picked up. I have found no larvae or evidence of textile etc damage. They have been active throughout the winter and don't appear to hibernate.
These are Spider beetles, either Ptinus sexpunctatus of Ptinus fur- I favour the former. The larvae feed on a wide variety of organic materials including many stored products, woolens and natural fabrics, feathers etc. in old abandoned birds nests and also the organic remains in old wasps nests/solitary bee nests. If you are only finding a handful birds nests, wasps nests may be the origin. They do not usually come in plagues, just a few now and again, and are not one of the more formidable household pests.