cuckoo
鵑 refers specifically to the cuckoo bird.
鵑 combines 鳥 (bird) with 肙, which likely contributes the sound. The exact historical development of 肙 is uncertain.
The right side is 鳥 (bird), and the left side 肙 looks like a small, compact shape. Picture a cuckoo bird calling from within a dense thicket.
For ケン, imagine a cuckoo bird named Ken who always calls out his own name: Ken -> ケン.
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