Have they started?

Have the blue tits finally actually started building their nest? I caught a couple of bits of footage today of them bringing some moss and some grass in. They also popped in and out a lot without anything!

Here they are in the box  together. The images you see above are small because they are cropped from the four camera view I get with my quad box that monitors all 4 boxes. When I thought I had some action, I switched it to just one camera, producing a clearer image, but I haven’t yet figured out how to remove the wording that is appearing on the page. You can see the small amount of nest material they have bought in so far.