Question Restatement: What is a reasonable inference that can be made as to why Noah chose a Raven and a Dove to send from the Ark to let him know the state the "World" was in?
Argument:
To argue that either bird was "conscious" of their purpose--is absurd, and a gross manipulation of the text, which is absent any any indication of conscious helpfulness, or rebellion on the part of the birds ...
Moreover, heaping conclusions from symbolism on top of an already ambiguous creation narrative, only leads to other inconclusive results--none producing a certain "fact" that can be relied on.
Therefore, it is reasonable to rely on what we know, what Noah would have observed, from science, and apply it to the passage, to find certainties from this text.
Conclusion: By the birds' actions, Noah could infer a lot about the World about him, because Noah would have certainly known that that the Dove and the Raven were two completely different birds: the Raven is omnivorous, a bird of prey, while the Dove is granivorous, (seed eating).
- The dove's seeming effort to take a twig, and bring it back to the ark, likely to make a nest, was probably not the Dove trying to communicate to Noah, (who could have interpreted that act many ways ...).
- Noah's observations of the Raven's and the Dove's ability, or inability, to find satisfactory food sources--outside of the Ark--were probably very reliable indicators of what was going on outside.
Raven as Omnivorous: Wikipedia Article
Dove as Granivorous: Wikipedia Article
Implications
It goes without saying that the ability of a Raven or Dove finding other food sources, outside of the Ark, would interplay with the discussion as to whether the "Whole World" was flooded, or whether "all life" was destroyed, (or if this grammatical structure was merely a Hasty Generalization to convey a general idea--which is used prolifically in Scripture).