From the White Goddess, by Robert Graves ....

In Gwion's Can y Meich (Song of the Horses), there is a series of  "I have been's."  One of them is: "I have been a crane on a wall, a wondrous sight." The crane was sacred to Delian Apollo and, before Apollo, to the Sun-hero Thesus.


The gods fled, disguised in bestial forms: "Mercury into an ibis, Apollo into a crane, a Thracian bird, Diana into a cat."

"Mercury invented the alphabet after watching the flight of cranes."

It was said by Hyginus that the original thriteen-consonant alphabet was taken by Mercury into Egypt, then brought back by Cadmus into Greece, and from there taken by Evander the Arcadian into Italy, where his mother, Carmenta (a Muse) adapted them into the then fifteen letters of the Latin apphabet.

He describes this Mercury as the same one who invented athletic games who was a Cretan, or of Cretan stock and , Mercury, who in Egypt was Thoth, the God whose symbol was a crane-like ibis, who invented writing and who also reformed the calendar.  The story may have been drawn from an Etruscan source: for the Etruscans, were of Cretan stock, and held the crane in reverence.  Cranes fly in V-formation and the characters of all early alphabets, nicked with a knife on the rind of boughs - as Hesiod wrote his poems - or on clay tablets, were naturally angular.

What material Mercury's bag was made of can be discovered in the parallel myth of Manannan, son of Lyr, a Goidelic Sun-Hero, predecessor of Fionn and Cuchulain, who carried the treasures of the Sea (i.e. the alphabet secret of the Peoples of the Sea) in a bag made of the skin of the crane;  and in the myth of Mider, a Goedelic Underworld-God, corresponding with British Arawn (eloquence) King of Annwm, who lived in a castle in Manannan's Isle of Man with three cranes at his gate whose duty was to warn off travelers, croaking out "Do not enter - keep away - pass by!"  Perseus's bag must have been a crane bag, for the crane was sacred to Athene and to Artemis, her counterpart at Ephesus, as well as being the inspiration for Herme's invention of letters.  The flying Gorgons, then, are cranes with Gorgon faces and watch over the secrets of the crane-bag, itself protected by a Gorgon head.  It is not known what sort of a dance the Crane Dance was that according to Plutarach, Theseus introduced into Delos except that it was performed around a horned altar and represented the circles that coiled and uncoiled in the Labyrinth.  My guess is that it imitated the fluttering love-dance of courting cranes, and that each movement consisted of nine steps and a leap.  As Polwart says in his Flying with Montgomery (1605): 

 The crane must aye
    Take nine steps ere shee flie.

The nine steps prove her sacred to the Triple Goddess; and so does her neck, feathered white and black with reddish skin showing through, or (in the case of the Numidian, or Balearic, crane) with red wattles.  Cranes make their spectacular migrations from the Tropic of Cancer to the Arctic Circle and back twice yearly, flying in chevron formation with loud trumpeting at an enormous height; and this must have attached them to the Hyperborean cult as messengers flying to the other world which lies at the back of the North Wind.

There is also the spirally-danced Troy-game (called the Crane Dance in Delos because it was adapted there to the cult of the Moon-Goddess as Crane.

In Greece the crane was associated with poets not only in the story of Apollo's metamorphosis into  "a crane, a Thracian bird" but in the story of Ibycus, the sixth century B.C. Greek erotic poet who, having spent the best part of his life in the Island of Samos, was one day set upon by bandits in a lonely place near Corinth and mortally wounded.  He called upon a passing flock of cranes to avenge his death and soon afterwards the cranes hovered over the heads of the audience in the Corinthian open-air theater; whereupon one of the murderers, who was present, cried out; "Look, the avengers of Ibycus!"  He was arrested and made a full confession.

Aug 6 - Sept 2 - C (Coll, crane) "Why is the Crane in the next place"?

"Not hard.  This the month of wisdom, and the wisdom of Manannan Mac Lir, namely the Beth-Luis-Nion, was wrapped in the crane skin. 

The omission of corr, the Crane, from the Irish bird-Ogham for the C-month is intentional, the contents of the crane bag were a close secret and all reference to it was discouraged.  

Robert Graves also makes reference to the crane as birds sacred to Kali. (White Goddess page 483)

At dawn you shall appear,
A gaunt, red-wattled crane,
She whom they know too well for fear,
Lunging your beak down like a spear
To fetch them home again.

The crane is the bird of wisdom - the chevron shaped formations of flying cranes are credited with the inspiration of letters - and letters are the basis of all learning.  The secrets and wisdom of the Celtic alphabet and calendar were said to be contained in a mythic crane bag, yet the crane is omitted from the Irish bird-ogham in the Book of Ballymote because, as Graves writes "the contents of the crane-bag were a close secret and all reference to it was discouraged.  The Crane was especially sacred to the Great Nine-Fold Goddess because of the nine steps a crane takes before flying. Also, the crane's neck feathers are white and black with reddish skin showing through, or with red wattles - the three colors of the Unicorn's horn. (The White Goddess Engagement Diary 1998, Peter Bogdanovich, page 143)