crested ibis
鴾 refers specifically to the crested ibis, a bird with a distinctive crest. The meaning is narrow and concrete, centered on this particular bird species.
鴾 combines 牟 (which may contribute a phonetic element) with 鳥 (bird) to denote a specific bird, the crested ibis. The exact historical development is uncertain.
The left side 牟 looks like a cow 牛 with a crest 厶 on top, and the right side 鳥 is a bird. Picture a bird with a cow-like crest: the crested ibis.
For ボウ, imagine a crested ibis balancing a bow on its crest: bow -> ボウ, and the bird proudly displays it.