--- a/net/minecraft/server/BlockMonsterEggs.java
+++ b/net/minecraft/server/BlockMonsterEggs.java
@@ -2,6 +2,8 @@
 
 import java.util.Random;
 
+import org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason; // CraftBukkit
+
 public class BlockMonsterEggs extends Block {
 
     public static final BlockStateEnum<BlockMonsterEggs.EnumMonsterEggVarient> VARIANT = BlockStateEnum.of("variant", BlockMonsterEggs.EnumMonsterEggVarient.class);
@@ -50,7 +52,7 @@
             EntitySilverfish entitysilverfish = new EntitySilverfish(world);
 
             entitysilverfish.setPositionRotation((double) blockposition.getX() + 0.5D, (double) blockposition.getY(), (double) blockposition.getZ() + 0.5D, 0.0F, 0.0F);
-            world.addEntity(entitysilverfish);
+            world.addEntity(entitysilverfish, SpawnReason.SILVERFISH_BLOCK); // CraftBukkit - add SpawnReason
             entitysilverfish.doSpawnEffect();
         }