Madeleine,

Hi, thank you for a very informative post. I have to admit never coming across the Sumerian term/symbol for the IDIGNA bird before.

The bird's association with the Tigris is interesting. Both the Tigris and Euphrates could well be seen as the twin streams emerging from the shoulders of the god Ea or Enki in Mesopotamian art. There is usually a bird of prey immediately above Enki . I wonder if this is your bird.

In the Wiki entry for Enki it says of this bird:

"An eagle descends from above to land upon his outstretched right arm. This portrayal reflects Enki's role as the god of water, life, and replenishment."

However, the bird is connected with just one of the streams, not both of them. Is this the Tigris?

As I show in Gobekli Tepe: Genesis of the Gods, the cult of Enki/Ea was at its strongest around the sources of the Tigris and Euphrates rivers, particularly in what was the Armenian Highlands of eastern Anatolia. It would be in this region that I would look for further evidence of your IDIGNA bird.

As to Kalahamsa, and the root of the word "kala," its association with time and calendars is pretty well established. It is the connection between this word and the hams swan-goose that is of interest. It associates the bird with cyclic activity, and time cycles in particular.

Let me know if you find out any more about the IDIGNA bird.