Bats can spawn in unusual places, such as in woodland mansions and beneath trees

As of the new changes to bat spawning, bats can be found frequently in woodland mansions. During nighttime, they also spawn commonly under trees, even ones with the smallest canopies.

To reproduce:

1. Locate a biome with many trees.
2. Use the following commands:

   /time set night

   /effect give @e[type=bat] minecraft:glowing 60

1. Notice that bats are spawning on the surface, beneath trees and often with no caves nearby.