I once spent ten minutes frantically looking for my wristwatch. It was very stressful, because I had to go to school, and I did not have much time left to catch the bus. So after a while (like I said, about ten minutes), I looked at my wristwatch to see how much time I had left. It took another 30 seconds for me to realize that I had been wearing my wristwatch the whole time.

Being smart does not save you (and not me, either!) from being dumb. And there have been times in my life when I was able to substitute inventiveness with stubbornness.

So there are upper bounds to everyone's intelligence, human or animal[0], genius or idiot. Given the variety we can observe in our fellow humans, I think it's fair to assume birds have their "village idiots", too.

[0] Except for barnacles, of course, but they are very discreet about it.