@JimsPhotos Where long feathers are habitually used as props on a substrate e.g. ground or tree, the central spine tends to have less of the feather blade around it.E.g. treecreepers, woodpeckers, hawks etc that start eating before they've killed their prey (so, not falcons).And of course... Microraptor! Primaries on both front and hind-limbs brushed the ground (and the prey) while wrestling on the ground, and since both also generated thrust through flapping, the tips needed protection.