What is an example of a behavior that might occur due to instinctual drift?

Instinctual drift refers to the phenomenon where an animal, after being trained to perform a specific behavior, begins to revert back to its instinctual behaviors that are more natural to its species. In the context of the choices provided, the behavior of chickens pecking for food exemplifies instinctual drift.

Chickens have an innate behavior to peck at the ground to find food, and if they are trained using food rewards, they might revert to this instinctive behavior even when other actions have been learned. This highlights how instinctive behaviors can dominate over learned behaviors, demonstrating the conflict that can occur between instinct and conditioning in animal behavior.

The other options depict behaviors that are either learned responses or specific trained tasks, which do not illustrate the concept of instinctual drift as clearly as the natural pecking behavior of chickens does.