1. Comfort and Affection: Pigeons are social birds and sometimes form strong bonds with humans, especially if they are regularly fed and cared for. When a pigeon preens a human, it could be a sign of comfort and affection. The pigeon may perceive the human as a part of its social group and express its care through preening.
2. Exploration: Pigeons are curious birds and may approach humans out of curiosity. Preening in such cases can be a part of the pigeon's exploratory behavior, where it uses its beak to investigate the human's hair or clothing.
3. Grooming Assistance: If a human has loose hair or clothing fibers that are easily accessible, a pigeon may try to preen them as a natural response to its instinct to groom. This behavior is more likely to occur if the pigeon is accustomed to being around humans and perceives the person as a non-threatening presence.
4. Seeking Attention: In some cases, pigeons may preen humans to gain attention or rewards. If a human responds positively to the pigeon's preening, such as by giving treats or petting the bird, the pigeon may learn that preening can lead to desirable outcomes.
5. Nest-Building Behavior: Pigeons often collect materials to build their nests, and in urban environments, they might find hair, clothing fibers, or other items from humans that can be used as nest-building materials. If a pigeon is particularly persistent in preening a human, it could be trying to gather material for its nest.
It's worth noting that the behavior of pigeons can vary greatly depending on their individual personalities and experiences. While preening a human is not typically considered a common or expected behavior, it can provide insights into the bird's comfort level, curiosity, or nesting behavior.