- Hooklets near a feather's base are small, microscopic hooks found on the barbs of birds' pennaceous feathers.
- They can be found in both contour and flight feathers.
- Each barb has a row of hooklets that face towards the feather's tip, and when pressed together they bind two adjacent barbs together.
- This forms the smooth overall surface of the feather and keeps it from becoming frayed.
- Without barbules and hooklets, the feathers of birds would become tangled, matted, and useless.