Nest

A great tit has made its nest in one of our boxes.  Well - it's not so much a nest as a pile of moss and grass, but that's what they do.  Once there are some eggs, a bit of a cup will be formed.  I don't expect to see the eggs for a few days. She won't start sitting until all the eggs are laid, and until then, she'll hide them away under the nesting material.