Why can the same soft barn-owl feathers that mute flight make rainy hunting worse?

Answer: Wet feathers spoil flight

Rain muffles every wing — Rain can mask background sounds, so this sounds tempting, but it does not make every wing quieter. For barn owls, the problem is the feather surface itself: soft, non-waterproof feathers lose their dry-flight advantage when wet. Sources describe rain as a hunting weakness, not an acoustic upgrade. The weather changes the instrument.

Wet feathers spoil flight ✓ — Right. Barn owl feathers are soft and quiet, but they are not especially waterproof, so rain makes hunting and flight worse. One source notes wet feathers increase noise and reduce efficiency; another describes heavy rain as a weakness of their soft feathers. That is the tradeoff: the surface that muffles dry flight becomes unreliable when wet.

Rain seals feather gaps — Sealing gaps sounds plausible because owl feathers have fringes and fine spaces, but water is not a helpful sealant here. The soft surface works when dry and flexible; wetting changes feather position and movement. Rather than locking in silence, rain pushes the plumage away from the condition that makes quiet flight work.