reindeer
麋 centers on the reindeer, a specific type of deer. The meaning is narrow and concrete, referring to this particular animal.
麋 combines 鹿 (deer) with 米 (rice), likely as a phonetic component. The exact historical development is uncertain, but the character is used specifically for the reindeer.
A deer (鹿) with rice (米) inside: imagine a reindeer eating rice, a memorable image for this specific deer.
For ビ, picture a reindeer buzzing like a bee: bee -> ビ, and the reindeer's antlers hum with the sound.