did a minor tweak

Assets/Scripts/Bird.cs

@@ -0,0 +1,57 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class Bird : MonoBehaviour
+{
+    // Start is called before the first frame update
+    
+    // public Movement controller;
+    public int birdType;
+    public Animator animator;
+    public float horizontalMove = -1f;
+    [SerializeField] float runSpeed = 40f;
+    private Rigidbody2D m_Rigidbody2D;
+    [SerializeField] float deltaY;
+    [SerializeField] float frequency;
+    private float elapsed = 0;
+    [Range(0, .3f)][SerializeField] private float m_MovementSmoothing = .05f;   
+    Vector3 m_Velocity = Vector3.zero;
+
+    //constructs an NPC using parameters
+
+    void Start()
+    {
+        m_Rigidbody2D = GetComponent<Rigidbody2D>();
+        horizontalMove *= runSpeed;
+        animator.SetInteger("Animation", birdType);
+    }
+
+    // Update is called once per frame
+    void Update()
+    {
+        // if(Movement.pause) {
+        //     animator.SetFloat("Horizontal", 0);
+        // }
+        // if (animator != null && !Movement.pause) {
+        //     animator.SetFloat("Horizontal", (horizontalMove/Mathf.Abs(horizontalMove)));
+        //     animator.SetBool("Airborne", !controller.m_Grounded);
+        // }
+        if(!Movement.pause){
+            elapsed += Time.deltaTime;
+            Vector3 targetVelocity = new Vector2(horizontalMove, Mathf.Sin(elapsed * frequency) * deltaY);
+                    // And then smoothing it out and applying it to the character
+            m_Rigidbody2D.velocity = Vector3.SmoothDamp(m_Rigidbody2D.velocity, targetVelocity, ref m_Velocity, m_MovementSmoothing);
+            
+        }
+        else {
+            m_Rigidbody2D.velocity = Vector3.zero;
+        }
+    }
+
+    //NPC movement determined by script in subclasses
+    // void FixedUpdate()
+    // {
+    //     controller.Move(horizontalMove *Time.fixedDeltaTime, false, false);
+    // }
+}