The topic is Europe and North America. Obviously this is the first set of matches in the group but I can’t shake the thought that, if Denver is going to make a run at qualification, this is the time to strike.
The most recent complete list for Denver we have is from 2016; I excluded any that I know have departed the collection. North American River Otter California Sea Lion Harbor Seal Grizzly Bear White-nosed Coati Dall Sheep Rocky Mountain Bighorn Sheep Cinereous Vulture Red-tailed Hawk Steller's Sea Eagle Bald Eagle Canada Goose Mallard Duck North American Wood Duck Marbled Teal Egyptian Vulture Ruddy Shelduck American White Pelican Prairie Rattlesnake Florida Kingsnake Copperhead Alabama Map Turtle Common Cooter Diamondback Terrapin Florida Red-bellied Turtle Mississippi Map Turtle Alligator Snapping Turtle Spotted Turtle Eastern Glass Lizard Everglades Rat Snake Ridge-nosed Rattlesnake Three-toed Box Turtle Barking Tree Frog Eastern Newt Blind Cave Fish (probably from Texas) Black Crappie Bowfin Dollar Sunfish Red Breast Sunfish Spotted Gar Rosefin Shiner Rosyside Dace Southern Redbelly Dace Giant Whip Scorpion Possibly tarantula, depending on species
To be fair to Denver, that is a good lineup. Would be interesting to see the conditions of living, but here are Rotterdam's species afaik. Bison Prairie dog Polar bear Arctic fox Snowy owl Northern raccoon Swift fox Rock squirrel California sea lion Puffin Common guillemot Black-legged kittiwake Greater roadrunner Burrowing owl Common eider Chuckwalla Gila monster Eastern king snake Colorado River toad And a few fish. So far based on the species lists, my vote goes to Denver.
Knowing Rotterdam pretty well ( and Denver not ) my vote goes to Rotterdam. Their North American area is great ( esp. IMO the Polar bear enclosure ) and the Arctic fox enclosure and also Bass Rock ( sea birds ) and the Oceanium ( large tunnel-aquarium with Atlantic fish and sea-turtles ) and the Sea of Cortez area are realy great and alos on conservation they do a lot ( some of the last Fire salamanders of Dutch orgin are kept in the Conservation center ). Also the breeding of Gila monsters is noteworth. The breeding-colony of the Caspian pelicans and the big pond in the middle of the old zoo with lots of waterfowl and loads of sliders is always worth to watch for a while. Because I don't know the Denver Zoo well but because the species-list is not bad I've made it a 2-1 score for Rotterdam.
Here are some photos of Rotterdam: Polar Bear (foreground) and Bison (background) Raccoons (photo showing that their exhibit has water for them to use) Swift Fox Sea Lion Atlantic Tunnel in Oceanium
And now Denver. @Echobeast might be able to clarify if Harmony Hill is in its final form or still needs further planting and modeling before it's complete. Harmony Hill (Brown Bears) Sea Lions and Seals Dall Sheep Bighorn Sheep
I gotta say, if those two lots of photos above were scrambled I wouldn't be able to say which photos were from which zoo. So looking at the species lists alone, I'm going 2-1 for Denver.
Harmony Hill is now planted and looks better than when it first opened. I will mention that it appears that dall sheep are no longer in the collection along with river otters and Stellar’s sea eagle with the closing of Bird World.