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Bird Mutant Brain

Based on game build 714014 | Last updated: 2026-03-03

Overview​

BirdMutantBrain is an AI brain component that governs the behavior of mutant bird entities in Don't Starve Together. It defines a behavior tree (BT) containing sequences and conditional nodes that handle movement toward a tracked swarm target, combat engagement, wall-patrolling, skeleton breaking, and conditional spit attacks (for spitter variants). The brain integrates with core systems such as combat, entitytracker, workable, and timer, and uses common helper behaviors like chaseandattack, panic, and leash.

Usage example​

local inst = CreateEntity()
inst:AddTag("bird_mutant_spitter") -- optional, enables spit logic
inst:AddComponent("combat")
inst:AddComponent("entitytracker")
inst:AddComponent("timer")
inst:AddComponent("workable")
inst:AddComponent("follower")
inst:AddBrain("bird_mutant_brain")

Dependencies & tags​

Components used: combat, entitytracker, timer, workable, follower.
Tags: Checks bird_mutant_spitter (alters behavior tree); uses player, playerskeleton, HAMMER_workable.

Properties​

No public properties.

Main functions​

OnStart()​

  • Description: Initializes and assigns the behavior tree (self.bt) based on entity state and tags. Constructs the root PriorityNode with the full behavior sequence, including conditional spit/spit-wait logic if bird_mutant_spitter is present.
  • Parameters: None.
  • Returns: Nothing.

Events & listeners​

None identified.

Helper Functions (Internal)​

The following helper functions are defined locally and used within the behavior tree:

  • GetSwarmTarget(inst): Returns the entity stored under "swarmTarget" in entitytracker.
  • GetSwarmTargetPos(inst): Returns the world position of the swarm target, or nil.
  • CanBirdAttack(inst): Returns a valid combat target if conditions (cooldown, state, range, or nearby players) are met; otherwise nil.
  • AttackTarget(inst): Invokes combat:TryAttack on the target returned by CanBirdAttack.
  • BreakSkeletons(inst): Finds a nearby skeleton tagged with playerskeleton or HAMMER_workable, and calls workable:WorkedBy(self.inst, 1).
  • shouldspit(inst): Returns true if a valid combat target is within TUNING.MUTANT_BIRD_SPIT_RANGE and the "spit_cooldown" timer does not exist.
  • spit(inst): Returns a buffered TOSS action on the combat target.
  • shouldwaittospit(inst): Returns true if the combat target is within 4 game units (2 tiles) and is valid.