We will know when a pole shift occurs because birds will be confused. They will start flying south, and people will say “wait, did you know you’re actually flying north now?”. Birds will be like “what? That’s south, I’ve flown that way every year for like 2 years”. And we’ll say “no, that was south until just recently. Now it’s north”. Pausing somewhat, birds will ask “is east and west still the same?”. We’ll reply “yes, but there’s a totally different reason for that”, which will confuse birds even more, of course. Birds will go on to say “well, can we still eat worms and bugs?”. To which people will respond “Of course you can, idiots”. I think the whole discussion will just go downhill from there, leading to the end of the world as we know it.
That was very “Douglas Adams”-ish. Well done, sir!