it was not hunted and eaten because it was 'common', but because it was 'royal'!

the wren, the wren the king of all birds...

made king by being clever, hiding in the feathers of an eagle, who climbed as high as he could, and higher than all other birds, to claim the title of king of all birds, when the wren jumped out and flew higher still.

It is thought by some that the wren as king of birds was used as a substitute display for the annual execution of the king for those in outlying areas who could not witness the ritual sacrifice themselves.

St. Stephen's story and day was imposed on the earlier pagan practice by the Christians, who made the wren into a snitch, whose noisy presence they say alerted the Roman legions of Stephen's hiding place.