Blue-tits making a nest

The blue-tits have been very busy.
A nest is build right close to my window, so that I have a perfect view on the building progress.
Its nice to see how they use different building materials.
Every time they first perch in the wisteria, and then fly into the nestbox.
By doing so, I can see all the materials they bring in.

The last thing they brought in today were feathers.
So I think the building of the nest is almost done.