What is the characteristic feature of falcons?

Falcons are distinguished by their long, pointed wings and a unique beak structure that includes notched or "toothed" edges. These adaptations are crucial for their hunting style and ability to capture prey in mid-air. The pointed wings allow for swift, agile flight, making falcons some of the fastest birds in the world. The notch in their beak serves a practical purpose: it helps them grip and dispatch prey effectively, a characteristic feature that sets them apart from many other bird species.

The other options, while they may describe different birds or traits, do not accurately capture the essence of falcons. Broad shoulders and small heads, for instance, do not define falcons specifically. They are also not primarily nocturnal; instead, most falcon species are diurnal, preferring to hunt during the day. Lastly, the size comparison with hawks does not hold universally, as falcon sizes can vary widely, and many hawks can be comparable or larger. Thus, the defining traits of long, pointed wings and a toothed beak are what truly characterize falcons.