How is a peacock a symbol of Eastertide?
What little we know of the images used by early Christians is what we can deduce from the use of images in the catacombs as decorations on their tombs. Many of the early images were borrowed from pagan symbolism to communicate an idea within Christian theology. Much as you might borrow a word from another language to express an idea that didn’t have an English word. For instance it is not uncommon to find a peacock on an early Christian tomb.
Christians adopted the symbol of the peacock to represent immortality and as an expression of their hope to follow Christ in His defeat of death. This came from an ancient legend that the flesh of the peacock did not decay. It is also associated with the resurrection of Christ because it sheds its old feathers every year and grows newer, brighter ones each year.
If the peacock is portrayed drinking from a vase it symbolizes a Christian drinking the waters of eternal life. In addition the “multitude of eyes” upon its stunningly beautiful fan tail, suggested the all seeing eye of God.