From Wild Wings Inc

Those tiny spikes around Luna’s eye are called pin feathers. During a molt, new feathers grow inside a protective keratin sheath, giving them their distinctive spiky appearance. As each feather finishes growing, the sheath dries out and flakes away, revealing a fresh new feather underneath. Molting helps owls replace worn feathers, keeping their plumage healthy for insulation, camouflage, and silent flight.