Koraki in Greek is κοράκι meaning crow or raven.
Noticing other articles on that site the authors name is on top just like the "koraki". It's probably a made up name used to make the story more interesting. I certainly found no other references to Koraki in the ancients texts applicable to this story.
The idea of Argo containing a branch of the Dodona Oak comes from the Hellenistic epic Argonautica by Appolonius of Rhodes. In Book 1, the Argonauts are getting in the ship preparing to leave Pagasae in Magnesia, when an astonishing thing happened:
And a strange cry did the harbour of Pagasae utter, yea and Pelian Argo herself*, urging them to set ...