Let me start with my apologies, I stayed up too late trying to prep these posts and accidentally posted Screech vs Scops too soon. I'll leave that open the full 24 hours from now as I intended, so if you've already been to that post, just head back over there after this and you can upvote your choice now.
Welcome to the Battle of the Giants! While the Great Grey would be the longest owl, it is also more feather by volume than most owls. Going by actual mass, the 2 contestants today are the biggest and baddest of them owl!
Blakiston's Fish Owl (new and improved name pending) could be call the King of the North. Found only in the coldest parts of Japan, China, and Russia, this is the biggest owl of all. The BFO is actually a closer relative to the Eagle Owls than to the Fish Owls, so we also have a bit of family rivalry today, though we still aren't sure if its true lineage yet. Males weigh in at up to 8 lbs /3.6 kg, and the females 10 lbs / 4.6 kg. Length is up to 28 in / 72 cm. They have unique fluffy plumicorns that look weighed down to the sides. As large as they are, they are still cavity nesters! This means they have very limited places left to exist, as they need very old undisturbed forest with dead trees large enough they can fit inside, while still being close to the water for them to hunt. This makes these owls very rare these days, as the remaining ones are in places inhospitable to humans.
The Eurasian Eagle Owl is likely much more familiar. This owl lives across most of Europe and Asia, with some similar relatives filling out the southern parts of Eurasian down into Africa. Size-wise it comes close to the Blakiston's, measuring around and inch or so, 3 cm, shorter. The mass of some can just about match the Blakiston's, but they typically are still short of tipping the scales. They survive in a much wider range of environments, including mountains, more open forest, steppe, and can even manage to do well in farmland or huge cities. This is the species of owl that Flaco, the rogue New York City owl sensation was. These owls nest in rock piles and cliff faces, so they are not bound to huge trees. The Eurasian Eagle Owl is also adapted to survive on a much wider range of prey than most owls, managing to hunt successfully enough to catch enough prey that would be too small for most birds its size.
Will the reclusive King of Cold warm your heart, or will the versatile Eagle Owl rock your world? Upvote your favorite!