diff --git a/src/main/java/org/bukkit/event/entity/CreatureSpawnEvent.java b/src/main/java/org/bukkit/event/entity/CreatureSpawnEvent.java
index 24c4ebf7d4..f60c86ffa5 100644
--- a/src/main/java/org/bukkit/event/entity/CreatureSpawnEvent.java
+++ b/src/main/java/org/bukkit/event/entity/CreatureSpawnEvent.java
@@ -147,6 +147,10 @@ public enum SpawnReason {
          * When a slime splits
          */
         SLIME_SPLIT,
+        /**
+         * When an entity calls for reinforcements
+         */
+        REINFORCEMENTS,
         /**
          * When a creature is spawned by plugins
          */