Gollum's second riddle

Gollum's mind, despite being an old one, knew the answer as well as you do. He hisses, "Teeth! Teeth! but we only has six!".

Then he asks his second riddle:

Voiceless it cries,

Wingless flutters,

Toothless bites,

Mouthless mutters

"Wind, wind of course."

"Time, time of course."