If you look carefully at the façades of Brussels houses you will discover that a very rich fauna: owls, cats, dogs, horses, cows, fish, etc.
Of all the aforementioned animals one seems to be rather abundant: the owl. This bird has been used as a symbol throughout history. In Europe the owl represents the wisdom. According to some sources the owl is also used by the freemasons to decorate buildings.
Here a few examples of owls I found during some of my walks.