Final answer:
The simile suggests the eagle's movements are controlled and deliberate, highlighting its grace and strength, similar to the precise and rhythmic movements of a swimmer doing the breaststroke.
Step-by-step explanation:
The simile "like someone swimming the breaststroke" suggests that the eagle is moving in a controlled and deliberate manner, much like a swimmer who is using the breaststroke technique. This comparison highlights the eagle's grace and strength, implying a sense of mastery over its movements, as well as a steady and powerful navigation through its environment. Often, describing an eagle in such a way underscores the precision and efficiency of its flight, similar to a swimmer's rhythmic and calculative strokes.