What do pigeons never forget?

Pigeons never forget certain things due to their excellent memory and cognitive abilities, which have been studied extensively. Most famously, pigeons never forget faces of people who feed them or who have been kind or cruel to them, they can recognize individual human faces and remember them for years, even after long absences, and will approach people who feed them and avoid those who have chased them. They never forget locations of food sources, water, and safe roosting sites, remembering precise locations of feeding spots and returning daily. They never forget their home loft location, homing pigeons can navigate hundreds of miles back to their home loft using magnetic fields, sun position, and landmarks, and they remember their loft for life. They never forget their mate and offspring, forming strong monogamous pair bonds and remembering their partner's cooing and appearance. They never forget migratory and commuting routes, remembering routes from roost to feeding areas. They also never forget negative experiences like being trapped or attacked, showing avoidance of places where they were harmed. Their spatial memory is so good that they can remember complex maze routes. So pigeons have remarkable long-term memory for faces, locations, mates, and routes, which is why they were historically used as messengers and why they return to the same balconies and parks where they were fed, sometimes for years.