Part two and about a week after part one. The pair of Eurasian Blue Tit have decided to use the nestbox so they start nest building. Initially this pair spent more time pecking at the entrance hole than nest building. But as it gets closer to time for the female to start egg laying the birds speed up the nest building.
So far most of the nest material is moss with some dry grass. I suspect one bird, the female, was doing more of the nest building at the stage although that will change.