beak, bill
嘴 centers on the hard projecting mouthpart of a bird: a beak or bill.
嘴 combines 口 (mouth) with 觜, which likely contributes the sound and originally referred to a bird's beak or a similar pointed shape. The exact historical development of 觜 is uncertain.
The mouth radical 口 beside the complex 觜 suggests a specialized mouthpart. Picture a bird's sharp beak as a pointed mouth tool.
For シ, imagine a bird using its beak to sip water: sip -> シ, and the beak is the tool for sipping.
beak; bill
shoebill (Balaeniceps rex)
pickaxe; pickax; pick
toucan
(something) not coming together (as one had hoped or expected); unfortunate turn of events; unexpected turn; (a) crossbill's beak (which has differently shaped upper and lower parts)
(mammary) nipple; teat
pied avocet (Recurvirostra avosetta)
Terek sandpiper (Xenus cinereus)
to stick one's nose into (someone else's business); to meddle; to interfere; to butt in
Snares penguin (Eudyptes robustus); Snares crested penguin; Snares Islands penguin
grosbeak weaver (Amblyospiza albifrons)
thick-billed murre (Uria lomvia); Brunnich's guillemot
jungle crow (Corvus macrorhynchos)
northern shoveler (species of duck, Anas clypeata); northern shoveller
wrybill (Anarhynchus frontalis)
insertion tip (e.g. of a catheter)
northern flicker (species of bird, incl. the yellow-shafted flicker and the red-shafted flicker, Colaptes auratus)
carrion crow (Corvus corone)
long-nosed mole (Euroscaptor longirostris)
spinner dolphin (Stenella longirostris)