Every Heathen worth his hammer knows Huginn (Old Norse “thought”) and Muninn (Old Norse “mind”) and Odin’s Day seems a good day as any to bring them up. They are ravens, a bird that still inspires an air of mystery in the modern world. These particular ravens daily fly all over the world and return to Odin with up-to-date information, keeping him informed as to the facts on the ground.
Grímnismál stanza 20:
Hugin and Munin fly each day
Over the earth.
I am worried about Hugin, that he not come back
And yet more worried about Munin
It is not surprising that one of Odin’s many names is the “raven-god” (hrafnaguð) – Huginn and Muninn not only bring Odin information but they perch on his shoulders (Gylfaginning), from where they can speak to Odin of what they have seen, Odin, Snorri tells us (Ynglinga saga) having taught them speech.
Odin’s choice was as wise as you would expect: It turns out that ravens are indeed very intelligent birds, far above the average for animals – up there with dolphins and great apes according to Markus Boeckle and Thomas Bugnyar from the University of Vienna.
All birds can speak of course (if not intelligibly to humans) but as Boeckle’s and Bugnyar’s study shows, ravens “ravens change their call characteristics depending on whether they hear former “friends” or “foes.” The study only covered up to three years, but bird memory may extend beyond that time.”
As Discovery.com reports:
So what does an angry bird sound like? When listening to a foe, a raven responds with a call that’s lower than normal in tone and starts to include “rougher characteristics.” The switch from the bird version of “Hey! How are you?” to “Buzz off!” is similar to how we communicate such differences in our speech.
Strangers get an even rougher response from ravens. This is the equivalent of a person yelling, “Who are you?,” if a stranger bangs on the door. There’s an interesting scientific phenomenon behind having a louder, lower and rougher-sounding response.
All of those qualities make the individual sound bigger in size. You may not consciously be doing that when you yell, but the effect is the same. Ravens similarly try to sound tough and large around strangers.
Is it any wonder that Odin employs ravens as his intelligence gatherers rather than some lesser bird? Modern Heathens (and historians) can debate the meaning of these two birds – as Simek says “Attempts have been made to interpret Odin’s ravens as personifications of the god’s intellectual powers”, an interpretation that is problematic since the names themselves are “unlikely to have been invented much before the 9th or 10th centuries” though evidence shows they were associated with Odin for centuries by this time.
 Rudolf Simek, Dictionary of Northern Mythology (D.S. Brewer, 1993), 164.