protected Behaviour nextResting() {
    Target restPoint = this.origin() ;
    final Nest nest = (Nest) this.mind.home() ;
    if (nest != null && nest.inWorld() && nest.structure.intact()) {
      restPoint = nest ;
    }
    final Action rest = new Action(
      this, restPoint,
      this, "actionRest",
      Action.FALL, "Resting"
    ) ;
    final float fatigue = health.fatigueLevel() ;
    if (fatigue < 0) return null ;
    final float priority = fatigue * Action.PARAMOUNT ;
    rest.setPriority(priority) ;
    return rest ;
  }