Heron

In the Celtic traditions, the heron and the egret meaning stand for autonomy, persistence, and longevity. In some Celtic lore, you will find an association of Heron with gods because of their peace-loving and calm nature.
Take Rhiannon for example, she was the epitome of protection, especially for the travelers. Her dominion encompassed all the magical waters. 
Rhiannon was the goddess of waters and lakes and as per the tales, herons are her reincarnation. This is why the Celtic Symbolism also addresses the heron as the Lady of the Lake.