In the wild, foraging for food is part of a bird's daily routine and occupies a large portion of his time - over half of his waking hours. Wild birds spend most of their time in 4 activities: foraging, social interaction, feather care, and sleeping. If foraging activity is not encouraged in pet birds, they have many more hours per day with nothing to fill their time. In many cases, social interaction is also limited. So now we have a bird with only two other options - feather care and sleeping.
Many times a bird will use the time on their feathers, and feather picking can result. This lack of foraging activity can affect a bird's physical and emotional well-being causing boredom, behavioral problems (such as feather picking), and a lack of natural curiosity.
Foraging challenges your bird by forcing him to look for his food instead of having it just put in front of him. Empty hours in the day will be filled with activity.