Across the lane from me is a 200 year old stone building that was used as storage by a builder and prior to that it may have been a stable.
On one gable wall there are two protrusions. Nobody has been able to say definitively what these were for. The most plausible is that the were entrances or perches for pigeons but I dont know if there is a hole in the wall just above the stones.
Photo at
https://www.trapbarn.com/wall/
Have any of you come across this feature before?