Variables affecting establishment of schedule-induced attack on pictorial targets in White King pigeons.

White King pigeons exposed to food schedules before introduction of a colored photograph of a pigeon showed sustained schedule-induced attack on that image; additional birds given an early introduction to both the photograph and the schedule subsequently attacked the image at lower rates. Other pigeons attacked a second photograph of a pigeon regardless of whether it was introduced early or late. The late-introduction procedure was also effective in establishing attack on a projected image of a conspecific. The combined results showed that 14 of 17 White King pigeons given a late introduction to a pictorial target exhibited sustained attack against it and that a pigeon's initial reaction to a photograph of a conspecific when introduced early was a good predictor of subsequent schedule-induced attack on it.