I am happy to announce that the Eurasian Tree Sparrow has begun making modifications to the nest. Today's visits were not limited to making space and moving feathers from one corner to the other of the nesting box, but additional material was carried into the nesting box. Twigs have now been added and these lie happily all over the place!
Additionally the visits were no longer limited to the 8-9 o'clock slot but continued on until ca. 11 o'clock, with however no additional visits in the afternoon as of 17:00 (last time I checked).