Difficulty Finding Wither Skeletons In Vulengate Red.

[XxHDxX]

Recently i was on a mission to farm some wither skeletons to get a beacon, but when i searched over four fortresses without a single sighting of ONE, im curious. Are the spawn rates reduced ? Or is my luck just that bad?

 

[Panserbjorne]

Gotta stick around in an area for a while, they take time to spawn and if multiple people are in the nether the spawn rates are spread out like with endermen in the end. Make sure there aren't any torches/light sources too!