Destroying Assests Not Permitted

Questions & Answers
1

public class birdScript : MonoBehaviour
{
private GameObject bird;

    // Update is called once per frame
    void Update()
    {
        if(gameObject.transform.position.y < -20)
        {
            Destroy(gameObject);
        }
    }

    public void hitCheck(float playerx, float playery)
    {
        if(playerx - 2 < gameObject.transform.position.x && playerx + 2 > gameObject.transform.position.x)
        {
            if (playery - 2 < gameObject.transform.position.y && playery + 2 > gameObject.transform.position.y)
            {
                DestroyBird();
            }
        }
    }
    void DestroyBird()
    {
        Debug.Log("die");
        bird = gameObject;
        Destroy(bird);
    }
}

So basically I have a birdPrefab and on that prefab I have a bird script. In the script I want to destroy the bird if hitcheck is called, but it says that it is not permitted. I have tried to look for this in other places but none of them had answers specific for destroying the gameObject.

2

From my understanding, Unity shows that message when the code would delete the actual asset in the project, rather than destroying the instance of the gameobject. Do you get the same error when calling Destroy(gameObject) rather than the assigned private variable bird, like you do in Update()?