Which characteristic defines true falcons?

True falcons are defined by their unique anatomical feature: a toothed or notched beak. This distinctive beak structure allows them to effectively capture and consume their prey, which often includes birds. The notch helps in gripping and tearing flesh, enhancing their ability to hunt and feed.

Additionally, while excessive crushing feet are a characteristic of some raptors, true falcons are known for their sharp, pointed talons that are better suited for catching rather than crushing prey. Their diet is broad, including small mammals and insects alongside birds, so the idea of feeding exclusively on birds doesn't accurately represent true falcons. Lastly, while maneuverability is a trait observed in falcons, it does not serve as the primary defining characteristic compared to the distinctive beak structure.