Ostrich

Ostriches were Talking Beasts in Narnia. They came into existence when Aslan created Narnia and called them and all the other beasts from the ground.

History
Ostriches are the largest flightless bird species on Earth, as well as the largest living bird alive today. Presumably, it is the same for their counterparts on Narnia, with the exception of Aslan, whose size dwarfed every animal and human.

The Lion, the Witch and the Wardrobe (Animated Version)
While regular ostriches weren't confirmed to have appeared, a green version resembling an ostrich called a Quetzalstrich was among the creatures in the White Witch's army.

The Lion, the Witch and the Wardrobe and Prince Caspian (4D Version)
In the 4D version (The Lion, The Witch, and the Wardrobe), the ostriches can be seen in the Battle of Beruna where they kick hyenas.

Later, in the second 4D version (Prince Caspian), the ostriches sided with the Old Narnians where they sided with Caspian X and fought against the Telmarines.

Link

 * Common ostrich