c#继承、构造函数和覆盖

我正在测试这个程序的继承，我有3个类(动物，鸸鹋，袋鼠)和主类。

鸸鹋和袋鼠源自动物类。

当我试图运行程序得到错误Emu.Bird()， Kangaroo.Mamel()是不合适的方法发现覆盖。我是通过一个随机的教程来做的，不确定"覆盖"以及它到底是做什么的。

static void Main(string[] args)
    {
        Emu e = new Emu("Emu","Brown", "is a bird");
        Console.WriteLine();
        Kangaroo k = new Kangaroo("Kangaroo","Dark Brown", "Is a mamel" );
        Console.ReadLine();
    }

头足类动物

 class Animal
{
    public string name;
    public string colour;
    public Animal(string MyName,string MyColour)
    {
        name = MyName;
        colour = MyColour;
    }
    public virtual void Show()
    {
        Console.WriteLine("Name: "+ name);
        Console.WriteLine("Colour: "+ colour);
    }
}

鸸鹋类

 class Emu:Animal
{
    public string bird;
    public Emu(string name,string colour, string eBird) : base(MyName,MyColour)
    {
        bird = eBird;
    }
    public override void Bird()
    {
        base.Show();
        Console.WriteLine(bird);
    }
}

袋鼠类

  class Kangaroo:Animal
{
    public string mamel;

    public Kangaroo(string name,string colour, string Mamel) : base(MyName,MyColour)
    {
        mamel = Mamel;
    }
    public override void Mamel()
    {
        base.Show();
        Console.WriteLine("Is a bird or Mamel ? " + mamel);
    }
}