Board Thread:General Mod Discussion/@comment-25565811-20150315235213/@comment-25101089-20150316003142

(The following also applies to butterflies, and birds [but birds count leaves to spawn instead of tallgrass])

They require a certain amount of tallgrass-type blocks nearby. (And need to spawn on a normal grass block.) They are now on the spawn lists for almost every biome.

Previously, the only condition was that they needed to spawn on grass. Therefore, to stop plains biomes being flooded with rabbits, I restricted rabbits to only forest-type biomes, where they were less noticeable. This had a number of bad effects:

-Plains biomes were boring for the most part, almost completely empty of life

-Rabbits still spawned here there and everywhere in forests even if all the trees and grass were removed

-When entering a forest biome from a plains one, enormous amounts of rabbits would spawn on the border, because as the forest was loaded into the game it became the only place in the entire world in which rabbits could spawn and therefore the closest edge was spammed with rabbit spawns

The rewrites I did fix all of these problems. Now the rabbits spawn semi-rarely but evenly all over the world, and more commonly in areas with denser vegetation (as one would expect) and you can stop them spawning by clearing away talllgrass, which also makes sense.