If you wanted to have the blueBird GameObject fly from left to right, you could add a scripted component to blueBird based on a new C# script class called MoveBird containing the following code:
using UnityEngine;
public class MoveBird : MonoBehaviour
{
public float speed = 1f;
void Update()
{
transform.Translate(speed * Vector3.right * Time.deltaTime);
}
}
As can be seen in the last line of the scripted component, when the public speed variable is changed, it adjusts the speed at which the sprite moves.
You can learn more about sprite masks at the following links:
- Sprite masks in the Unity manual: https://docs.unity3d.com/Manual/class-SpriteMask.html
- InScope Studios video (it's a few years old but still useful): https://www.youtube.com/watch?v=1QktsHJwXCQ