A number of times we have implemented nest places for Swifts in thick brick walls (e.g. here), this is just another example where we did something slightly different. The wall in question is about 35 cm thick - 3 layers of bricks.
First we removed an outer stretcher, which was quite easy with lime mortar. The next layer of brick was more difficult and had to be drilled out and removing small pieces. We managed to make a cavity over 200mm deep into the wall. We glued a nest form down at the opposite corner to the entrance:
We made a brick slip 25mm deep with an entrance. This was glued to a piece of 3mm ply in order to stop mortar being pressed into the nest space. One could have used slate or cloakboard for this. With this idea, there is no need for a nest chamber:
