It's Not Always Obvious

What makes a bird's brain tick?  I read a book last year in which the author suggested that birds weren't just nonhuman, but perfectly alien. Whatever goes on in their minds is probably a good deal different than anything we can read. 

It's as simple as the idea that a giant glob of peanut butter, fallen because the temperatures were a little too warm to hold it to its feeder, went largely unnoticed for three days.  In photo after photo, the birds went for the tougher shot while the easy pickings were ignored.  And let's be clear: the birds in question have strong enough legs for this.  All I saw was this one titmouse doing the thing.

Has the pattern of behavior established itself too well?  Are the birds less observant than robotic? does the novel puzzle them too much?  I have seen too much to believe they're dumb, or unobservant.  Some seem incredibly clever.  Whatever it is, the bird action can't be readily guessed: it's not that obvious.