This is the 5584th most frequent Japanese word.
くるくる
"くるくる" means "spiraling, spinning, or rolling repeatedly and nimbly."
In this sentence, 'くるくる' describes the rotational action of the clock hands in a repeated, circular manner.
時計の針がくるくる回っています。
The clock hands are spinning round and round.
Here, 'くるくる' conveys the circular and lively motion of the bird flying.
小鳥が空をくるくる飛び回っている。
A small bird is flying around in the sky in circles.
In this usage, 'くるくる' illustrates the spiraling action involved in curling her hair.