Swifts 22-07-11

Checked up on the progress of the two Swift chicks up in the loft ,seconds before an Adult sat in the opening surveying the outside eventually flying off, the two young are progressing fantastically and its fantastic to watch ,there is another nest located above the drive here there is a collection of droppings on the ground and has been for sometime indicating the young are backing up to the entrance to defecate whereas these two have only recently started to do this , below this nest is the roof of the  utility room  there is a good growth of Lichen that apparently needs the presence of bird droppings to start growing.

In the previous clip I thought it was one of the parents present ,but now think it was a prospecting  bird that went in looking for a site