shrike
鵙 refers specifically to the shrike, a bird known for impaling its prey on thorns.
鵙 combines 貝 (shell) and 鳥 (bird). The character was created to represent the shrike, but the exact reason for the 貝 component is uncertain.
A bird (鳥) with a shell-like (貝) hooked beak, like a shrike that impales its prey on sharp points.
For ケキ, imagine a shrike making a sharp 'keki' sound as it strikes: keki -> ケキ.