What is a malar stripe?

A malar stripe refers specifically to a marking on the face of certain birds, including the Peregrine Falcon. This stripe typically appears as a dark line that runs from the bird's beak down to its throat or cheek. This distinctive feature is not just aesthetic; it also serves functional purposes. The dark coloration can help reduce glare from sunlight, improving the bird’s hunting efficiency by allowing it to see more clearly while pursuing prey.

The other options do not accurately define what a malar stripe is. For example, it is not related to a type of feather or a behavior exhibited during hunting. Although female falcons have various traits that distinguish them from males—like size and sometimes coloration—this characteristic specifically pertains to a facial marking and is not limited to females or exclusive to them.