Owls and snakes declare the owls' superiority over birds because owls regurgitate pellets instead of producing regular droppings, which owlsdo! And the fact that plenty of other birds, such as crows, also regurgitate pellets is never even touched upon.
They certainly wouldn't be the first race or group of people to think — literally in this case — their sprink don't stink.
Ahem. "Although owls did digest the soft parts of their food in a manner similar to other birds, and indeed passed it in a liquid form, for some reason they were never associated with these lesser digestive processes."
While that explains the first bit, it doesn't explain the second. And that's not even the only example of Dan Browned. The book also goes on to claim that burrowing owls dig all their own burrows (not true; most don't); and that no owls are ever up during the day (some, such as the short-eared owl and great gray owl, are, on occasion).
Heck, snowy owls spend a fair amount of time up during the day in spring and summer, due to their natural range being fairly far north - when the sun is up for longer amounts of time, you really don't have much choice. (Though this does get some mention with the owls in the Northern Kingdoms.)
Not to mention that seagulls, the butt of owl jokes on the subject, also regurgitate pellets.
These books also continuously have the owls taking note of various scents. Owls are one of the primary predators of skunks. Think about that for a moment. In truth, most birds (except for kiwis, members of the tubenose family, and some vultures) have almost no sense of smell.
Multiple times they do mention how an owls' sense of smell is pretty terrible, and they only tend to notice something when it's particularly strong(like, say, hagsfiends).
If a skunk isn't "particularly strong," I don't know what is, and the owls often take in faint or sweet smells along with strong or foul ones. The first mention of owls not having that great a sense of smell was in book eight, and that was only because they were being compared to wolves. A skunk attempts to spray Coryn partway through the book. The kicker is that he's safe from the smell because he's flying too high to be hit, when in reality it shouldn't bother him even if it did hit him.
The idea that crows are idiots. They're not. In fact the corvids (crows/ravens/etc.) are among the smartest birds - usually considered the smartest. The magpie trader and ravens, however, are portrayed as somewhat smarter than their crow cousins, though nowhere near as smart as the owls. In real life, it's the other way around: owls range in intelligence from roughly average as birds go to fairly smart, but typically nowhere near the level of corvids.
The owls, as essentially narrators of the series, are speciesist and thus unreliable?
This could be it, except that the crows' behavior in the books seems to support the "idiot" stance. Maybe the author just doesn't like crows...
Actually, it's more that the two sets don't really like each other. I once witnessed a horned owl being harassed by a small murder.
In early books, falling into the ocean is treated as a real danger because the owls' feathers would become saturated and they would not be able to lift off again. Then we come around to the books entailing the story of Hoole, and suddenly we've got owls willingly diving into the ocean to catch fish, and the sea is now only dangerous to hagsfiends. Never mind the fact that even fishing owls really only grab for fish from the surface, rather than diving.
Kind of a mix of Fridge Logic and It Just Bugs Me!. Weapons like battle claws and swords of ice were somehow invented long, long before fighting with burning branches. Even if we decide to roll with the idea, one would think that it wouldn't take a few hundred years for some owl to figure out that a lighted branch could be useful in battle, but apparently it simply didn't happen before the Band came along.
Fighting with fire did exist, it just wasn't popular until the Band made it into a strategy. Plus, think about it- owls usually live in or near combustible objects. How many innocents could one kill if they decided to fight with fire on unknown territory? Of course, hagsfiends wouldn't be concerned about that, but it's stated that hagsfiends aren't the sharpest tool in the shed.