Metaphysicality

So, what exactly counts as physical evidence when reporting a bird sighting? The dead bird itself (aka, a specimen) is an obvious choice, but does any other form of what we often call "physical evidence" have a similar degree of "reality"? That is the question that Rick Wright takes up in a recent post from Aimophila Adventures. I've got to say that an apprentice librarian such as myself ought to be able to come up with some trenchant arguments on this question, but unfortunately it usually takes me a while to come up with my trenchant arguments. So, in the meantime, I'll refer you to the original post.