What are the most distal feathers on a bird's wing called?

The most distal feathers on a bird's wing are referred to as primary feathers. These feathers are critical for flight, as they play a significant role in creating lift and thrust. Attached to the outer part of the wing, primary feathers are typically longer and stiffer than other types of feathers, enabling birds to maneuver during flight efficiently.

In contrast, secondary feathers, which are found closer to the bird's body than the primary feathers, assist in lift but are not considered the most distal. Down feathers provide insulation and are located beneath the contour feathers for warmth, while tail feathers, though critical for balance and steering during flight, are located at the tail rather than on the wing. This distinction emphasizes why primary feathers are the correct answer when identifying the most distal feathers on a bird's wing.