The Migration Patterns of Imaginary Birds

The White Bird of Yamato-dake

Now Yamato-dake no Mikoto, taking the shape of a white bird, came forth from the misasagi [upper class tomb], and flew towards the Land of Yamato. The Ministers accordingly opened the coffin, and looking in, saw that only the empty clothing remained, and that there was no corpse. Thereupon messengers were sent to follow in search of the white bird. It stopped on the plain of Kotobiki in Yamato. Accordingly in that place a misagari was erected. The white bird flew on again until it reached Kahachi, where it rested in the village of Furuchi, and in this place also a misasagi was erected. Therefore the men of that day called these three misasagi "the white bird misasagi." At last it soared aloft to Heaven, and there was nothing buried but his clothing and official cap. The Emperor, wishing to perpetuate the fame of his services, established the Takeru Be. This was in the 43rd year of the Emperor's reign.

From the Nihongi (the second oldest book of Japanese Mythology)

I mainly wanted to put this in, because Japanese mythology is, I think, some of the most interesting in the world (this has a lot to do with the sudden introduction of writing in Japan, which made the transition from oral to literate society quicker than in most places).

The piece brings out the largely varying role of the bird as a symbol of death. In Irish mythology the role is quite dark, in Akkadian mythology its baffling, here the role seems to be mostly positive, despite the fact that the afterlife in Japanese mythology is fairly horrific:

Thereafter, Izanagi no Mikoto went after Izanami no MIkoto [who had died], and entered the land of Yomi. When he reached her they conversed together, and Izanami no Mikoto said: 'My lord and husband, why is they coming so late? I have already eaten of the cooking-furnace of Yomi. Nevertheless, I am about to lie down to rest. I pray thee, do not thou look on me.' Izanami no Mikoto did not give ear to her, but secretly took his many-toothed comb and, breaking off its end tooth, made of it a torch, and looked at her. Putrefying matter had gushed up and maggots swarmed . . . Izanagi no Mikoto was greatly shocked and said: 'Nay! I have come unawares to a hideous and polluted land.' 

Later on, when the Emperor attempts to move the guards of the empty tomb from guardianship into labor, one of the guards turns into a white deer and runs off.

Japanese mythology is so amazingly awesome, unfortunately they aren't big into bird myths.

The Irish Raven

 " . . . craving for carrion, the dark raven shall have its say, and tell the eagle how it fared at the feast, when, competing with the wolf, it laid bare the bones of corpses."

- Beowulf

In Irish mythology, the raven is said to take the souls of the dead, and is the form several goddesses take on the battlefield. The source of this myth is clearly the presence of ravens after a battle, eating the corpses of those left behind.

Source: Mary Jones Celtic Encyclopedia, ravenfamily.org

Imaginary Birds: The Akkadian dead

To Kurnugi, land of [no return],

Ishtar daughter of Sin was [determined] to go; 

The daughter of Sin was determined to go 

to the dark house, dwelling of Erkalla's god, 

to the house which those who enter cannot leave, 

On the road where travelling is one-way only, 

To the house where those who enter are deprived of light,

Where dust is their food, clay their bread. 

They see no light, they dwell in darkness 

They are clothed like birds, with feathers. 

- "The Descent of Ishtar to the Underworld" 

From Myths of Mesopotamia, Oxford World Classics,