Odin Ravens are fairly easy to spot due to the fact that they are green glowing birds. I don’t know what Odin was thinking with these. Stealth is not his strongest skill it seems. The ravens are fairly random in where they show up. They are always in the same place although some of them do fly around in a pattern. There are 51 ravens in total to destroy and finding them all will unlock the Allfather Blinded Trophy.
To collect a raven you must kill/destroy it. This is easily done by throwing your Leviathan Axe at them. I would suggest using the light throw rather than the heavy throw. The ravens will die with a single hit, no matter which you use. Since the light throw is far quicker, it will help you get them much easier. For the birds that do not move it might not be an issue. Since there are a lot of flying birds too, having the quicker speed makes all the difference.
If you are looking for the locations of all of Odin’s Ravens you can check out the video guide below and it will show you where to find all of the ravens in the game. Some areas may not be accessible if you are in the early parts of the game. Story events and specific weapons are required to progress to some areas. None of the ravens are missable.