Started a new map centered in a mushroom island recently. As part of my build, I built a pen for all the Mooshrooms I could find on the island. (about eight) Unfortunately, they all got wiped out during a lightning storm (presumably by two strikes since there were two skeleton horse traps in the pen.) I have searched the entire island repeatedly looking for any respawns, but after several hours, I couldn't find any. I can only conclude that once the initial spawns are gone, they are gone for good.
Steps to reproduce
Make a creative world using mooshroom biome seed 1404986100
Make sure cheats are on.
Fly all around the biome for a while until enough mooshroom cows spawn.
Now type /kill @e
Observe that the mooshroom cows don't ever re-spawn.
Comments 3
I found a way to get Mooshrooms to spawn:
enchant a shovel with silk touch and gather some grass blocks
plant grass blocks in a spot in a mushroom biome, preferably isolated from any mycelium that may grow nearby
Mooshrooms should spawn 2-6 at a time on the grass during the day.
Seems nothing spawns on mycelium, but mooshrooms will spawn exclusively on grass in these biomes. At one point I had a sizable herd until I decided to give them all a lava bath, I keep finding more on my lawn almost every time I return to my house.
This has been the case since at least 0.14.0 or thereabouts. Seems like the Mooshrooms only spawn on generation of the island. I assumed it was WAI so didn't raise it, added vote.