Raccoons. 
If you can tell the fine structure of a soft wriggling thing’s spines, no doubt you could tell a flint has been knapped. It is extraordinary to claim that rocks cannot, under some conditions, survive for hundreds of millions of years.
But I do doubt. I doubt a lot. The Burgess preservation is distinctive because it stands out from its ground mass, and because of the rare conditions that . How are the details on a knapped flint going to stand out
Rocks, yes, but not in the same shape they were to start off with.
Almost any rock type, suitably durable for a tool, would be extremely well preserved in such a shale. Flint tools would be virtually uncompressed, leaving all the clues as to their ‘intelligent design’. The deformable matrix accommodates most of the small-scale strain incurred during the shallow paleodepth to which this type of formation is buried.
Thing is though, birds evolved for flight (this affects the basic anatomy even of flightless birds), and big brains are heavy. It is therefore hard to imagine an environment of near-Earth gravity and atmospheric pressure where a flying animal or descendant of flying animals evolves intelligence.
What term would you suggest for human-equivalent “intelligence”? Abstract cognition? Really, in common usage, “sentience” has come to mean humanlike intelligence. The OP is not concerned with semantics.
My candidate for intelligence? Dogs, Mice and cats. Suitably mutated, of course.
But you’ve just imagined one. Flightless birds don’t have this problem.
The major large animal survivors of the KT impact were those creatures which lived in or near rivers or on the coasts, so I, for one, welcome our new otter overlords.
The terrifying march of the penguins towards world domination continues … :eek:
But seriously, if a squirrel-like creature can evolve into us, I can easily imagine a parrot or crow-like creature evolving, under the right conditions, flightlessness and human-style intelligence.
Unless they grow super strong wings like seraphim. In which case we’re doomed.
This leads to the logical conclusion that all birds must be destroyed.
Yes, but as noted the past flight-oriented evolution seems to determine the basic anatomy of flightless birds – I mean, look at the size of the head on an ostrich or a penguin.
Sapience/Sapient has been used. But yes, “sentience” is used to mean “having humanlike intelligence” as often as not.
The cranial size of one species doesn’t restrict the evolutionary potential for its adaption in another. The vertebrate skeletal arrangement is highly conservative in elemental terms, but not with an individual component’s morphology or adapted use. If circumstances had conspired differently it is not inconceivable that the progeny of Phorusrhacos might be king of the hill right now.
Exactly. The limiting factors on the avian brain–largely flight–is “so far.” Yes, even flightless birds are still limited by the small brainsize of their ancestors. But there’s nothing that limits the future growth of such brain size. The human anatomy underwent quite some serious changes to accommodate it (e.g., female pelvic bone). There’s no reason to suppose such drastic changes couldn’t occur in an avian evolution that favored brain size. In fact, the other advantage of flightlessness in this respect is freeing up the wings for other possible uses: if the fin of a cetacean can evolve from the fully articulated “hand” of its ancestor, who’s to say a bird’s wing structure might not “revert” to the articulated form of its dinosaur ancestor, and eventually even rotate a thumb? Psittacines have two toes forward and two back–as do owls–and can be quite adroit with them.
Emphasis added.
IMO this whole question is very anthropocentric and really anthropomorphises the whole question of intelligence. Why are making tools, buildings, cars, computers etc. the hallmark of intelligence? Because those are behaviors found in humans, and we are humans. So really, the question we’re asking is not “would other animals become sentient,” (or, similarly, “does sentience exist elsewhere in the universe”) it’s would they become humans and to what degree (or do humans exist elsewhere and to what degree).
What if ants asked the same, self-centered type of questions and completely missed the point?
Raccoons have excellent hand manipulation, and of course there’s the panda’s thumb which is a different bone, but works fine.
All apes do have opposable thumbs, you know. Go to the zoo and watch them as they eat oranges or bananas, or tear paper. Their thumbs work like ours, and their big toes outdo ours by a long shot.
If you ever meet my cats, your skepticism will disappear.
That’s fine for diagenesis, but I’m talking about the sort of tectonic history that’d soon turn that shale into slate. I’ve got some experience with this - the Dwyka tillite here is a dropstone diamictite that contains clasts of quartzite, basalt etc. in fine matrix - I assure you, this has not rendered them immune to stress and strain.
If you invoke the deviatoric strains required to produce a slate, then clearly yes. But short of these, stone tools could potentially be very well preserved (my Echinocorys sulcatus is nodding in agreement with me).