Which of the following best defines the term 'flushing' in falconry?

Flushing refers to the action of causing quarry, such as game birds, to take flight. This term is particularly relevant in falconry because it describes a critical moment when a falcon or hawk is engaged in hunting. When the quarry is flushed, it becomes disturbed and flies away, which provides an opportunity for the raptor to pursue it. This is a fundamental aspect of hunting with birds of prey, as the success of the hunt often depends on effectively flushing the target.

The other options focus on different aspects of falconry and bird behavior. Training a bird to return pertains to recall training, which is vital for managing a bird but does not relate directly to flushing. Scaring away potential quarry could imply that the bird is driving away prey, but this is not the same as flushing, which is more about enabling the prey to flee. Finally, settling a bird to a perch involves training and handling practices rather than the act of making quarry take flight. Each of these concepts is important in falconry, but only the act of causing quarry to take flight directly defines flushing.