Sometimes it’s about money. California, for instance, designated gold as its state mineral (duh, Golden State); the state rock is serpentinite because (a) we’ve got a lot of it, and (b) it’s the principal source of chrysotile asbestos, and the choice was promoted by the California asbestos industry.
Virginia’s state flower is ham.
Ha! Just kidding. It’s dogwood.
Which makes only slightly more sense.
North Carolina and Virginia are interesting because they are neighboring states that both have the same state bird and flower: the cardinal and the dogwood. I’m not sure if this is due to a lack of imagination, or some sort of plan for eventual unification that foundered when they couldn’t agree on a common state dog. (North Carolina’s is the Plott Hound, Virginia went with the American Foxhound).
In most years, New York is second or third in maple syrup production. Wisconsin is generally in the top five. West Virginia has little commercial maple syrup production but sugar maples grow there and some people tap them. I remember reading about a maple syrup festival when I lived down there, but I don’t remember where it was exactly.
NC has a state dog, the Plott hound. Not sure if any other state has a state dog.
Louisiana - Catahoula Leopard Dog
Maryland - Chesapeake Bay Retriever
Massachusetts - Boston Terrier
Pennsylvania - Great Dane
South Carolina - Boykin Spaniel
Texas - Blue lacy
Virginia - American Foxhound
Wisconsin - American Water Spaniel
Yeah, that was a good movie.
Ohio’s state beverage is tomato juice. And I’m puzzled why Kansas’ state toy is the Etch-a-Sketch but Ohio has no state toy – the Etch-a-Sketch is made by Ohio Arts in Bryan – at least until they moved manufacturing to China in 2001. 
The sugar Maple makes sense for Wisconsin. They’re all over the place.
I want the state bird changed to the Bald Eagle. We have a very healthy population and I despise Robins.
Wisconsin state dance Polka. They need to stop letting teachers do a campaign where they brain wash naive children to persuade legislatures we need a state something.
I had always heard that when Louisiana was officially designating many of its state symbols, one legislator nominated one of his esteemed colleagues as the official state fossil. According to a quick googling it was Senator Edgar Mouton
In cross checking that, it seems Mouton would have only been 47 years old at that time which would hardly qualify him for fossil status, but it still makes a good story.
I’d wish that Michigan would choose Kirtland’s Warbler, which only breeds in the state (some recent reports in Wisconsin tho), over the Robin, which breeds almost everywhere.
And to add to your sum of trivial information, the list of state animals, songs, trees, etc. is called the “state pantheon”.
No, I have no cite for this, so don’t ask. Just take my word for it.
I’m a native Jerseyite (presently exiled to upstate New York), and I proudly cherish my Knobbed Whelk shell that I found on a Jersey beach. I didn’t know it was our official shell, though.
Another fine emblem of the fine state of New Jersey. (And we’ve had it since 1974, while Vermont adopted it only in 1978, the copycats.)
Ha! Arkansas adopted it in 1973. 
The philosopher-kings of the Ohio General Assembly resisted the temptation to make a cheap joke about one of their peers, and instead selected the Trilobite as the official state fossil: Statefossils.com
Maybe it was his birthday and they were messing with him.
I remember that story being played out in Colorado, with some Colorado state legislator who actually was very old. The Stegosaurus became the CO state fossil in 1982, so I don’t know whether they cribbed the gag from LA’s 1976 proceedings, or thought of it on their own.
Am I really the first doper to post this link from the op-ed page of today’s NYTimes?
As I said a lot of these “symbols” are voted for by kids in elementary and junior high schools so that would explain a lot