One not still searching for hobby? (8)

I believe the answer is:

twitcher

I believe this clue is a double definition.

'one not still' is the first definition.
(someone who isn't still)

'searching for hobby?' is the second definition.
(a hobby is a bird - a twitcher is a birdwatcher)

(Other definitions for twitcher that I've seen before include "Spasmodic" , "Measure; creep" , "One not still" , "Name for a keen bird-watcher" , "Rare bird spotter" .)

I've seen this clue in The Independent and The Sun.

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