People often have a desire to interact with wild animals in the park. It seems like our first instinct is to feed animals because it encourages them to come closer and seems to make them happy.
This real Tripadvisor review for St. James’s Park demonstrates excitement about park animals and this common method of interacting with them.
In a consistently visited, relatively low-predator park like St. James, a visitor bringing nuts for squirrels is probably safe! Unfortunately, this impulse can sometimes cause problems in different scenarios. For example, if visitors feed squirrels whatever unhealthy food they happen to have with them or there are predators around and the familiarity encouraged with humans makes squirrels less afraid of dangerous animals.
As for the safety of the humans, squirrels are almost never found to be infected with rabies (but I know this because I was bitten by one as a child – so there’s that).
One goal of the squirrel listener in the park kit is to give park visitors a safe and healthy way to interact with animals.
Smart City Design Workbook 
