C# error

namespace Flappy_Bird.Entites
{
    class Bird

    {

        public Texture2D[] Textures;
        public float Rotation;
        public float YSpeed;
        public int texturePosition;
        public Vector2 Position;




        public Bird()
        {
            Textures = new Texture2D[3];
            this.Textures[0] = Statics.CONTENT.Load<Texture2D>("Textures/bird1");
            this.Textures[1] = Statics.CONTENT.Load<Texture2D>("Textures/bird2");
            this.Textures[2] = Statics.CONTENT.Load<Texture2D>("Textures/bird3");
            YSpeed = 0;
            this.Position = new Vector2(150, 300);
        }


        public void Update()
        {
            YSpeed += 0.2f;

            if (YSpeed > 0.5)
                Rotation = 1f;
            else
                Rotation = -1f;
        }

        public void Draw()
        {
            Statics.SPRITEBATCH.Draw(this.Textures[this.texturePosition], this.Position, null, Color.White, this.Rotation, new Vector2(20, 20),1f, SpriteEffects.None, 0f);
        }
    }
}
namespace Flappy_Bird.Screens
{
    public abstract class Screen
    {
         public virtual void LoadContent() { }

         public virtual void Update() { }

         public virtual void Draw() { }

    }
  }

namespace Flappy_Bird.Screens
{
   public class GameScreen : Screen
   {

       public Texture2D background;
       public Entites.Bird Bird;

       public GameScreen()
       {

       }
       public override void LoadContent()
       {
           background = Statics.CONTENT.Load<Texture2D>("Textures/background");
           Bird = new Entites.Bird();

           base.LoadContent();
       }


       public override void Update()
       {
           Bird.Update();
           base.Update();
       }


       public override void Draw()
       {
           Statics.SPRITEBATCH.Begin();

           Statics.SPRITEBATCH.Draw(this.background, Vector2.Zero, Color.White);

           Bird.Draw();

           Statics.SPRITEBATCH.End();
           base.Draw();
       }
   }
}
namespace Flappy_Bird
{
    public class FlappyGame : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;


        Screens.Screen currentScreen;
        public FlappyGame()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            Statics.CONTENT = Content;

            Managers.InputManager input = new Managers.InputManager();

        }

        public override void Initialize()
        {
            base.Initialize();
        }


         public  override void LoadContent()
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);
            Statics.SPRITEBATCH = spriteBatch;

            currentScreen = new Screens.GameScreen();

            currentScreen.LoadContent();
        }
        public override void Update(GameTime gameTime)
        {
            Statics.GAMETIME = gameTime;
            Statics.INPUT.update();

            currentScreen.Update();

            base.Update(gameTime);
        }
        public override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            currentScreen.Draw();
            base.Draw(gameTime);
        }

    }
}