The active, goal-seeking and exploratory phase of behaviour that precedes the more stereotyped consummatory behaviour that the animal exhibits when it reaches its goal. Upon reaching the goal, appetitive behaviour normally ceases.
In some cases, there are difficulties in separating appetitive goal-seeking behaviour from other forms of behaviour. For example, the nest-building behaviour of the blackbird (Turdus merula) begins with the search for large twigs to form a foundation. Small twigs are then collected to form the sides. The nest cup is made from mud and lined with fine grass and hair. While we may wish to regard the completed nest as the bird's ultimate goal, there are difficulties in distinguishing between the appetitive and consummatory aspects of the nest-building behaviour. One possibility is to regard the search for each twig as an appetitive episode, and its placement in the nest as a consummatory response. Another possibility is to regard the whole chain of behaviour as appetitive, and completion of the nest as consummatory.
The concept of appetitive behaviour is not relevant to all types of behaviour. We would not normally think of animals as showing appetitive responses for avoidance of noxious stimuli, or alarm responses. Similarly, some appetitive behaviour, such as that shown by ambush predators that lie in wait for prey, is characterized by inactivity rather than by the active searching normally thought of as appetitive.