gives the lyrics as the man searching "for a fine ten pointer or a royal 'O' -- the O in quotes meaning, if I understand English, it represents a word that starts with O, popularly abbreviated by an O, or it might be something shaped like an O, I don't know what.

I realized this morning that in all my years I've probably spent less than an hour with a dictionary. All my knowledge of words comes from hearing and reading, from context. So I've gotten pretty good at figuring things out that way. So I figure a royal 'O' is an animal that you could hunt, and someone hunting deer wouldn't be also hunting bugs or little birds, it would be a largish animal.

gives a list with animals that start with O, from the Oahu Amakihi to O’shaughnessy’s Keeled Iguana. I think we can rule out fish, most birds. This is Scotland, right? You don't have alligators, crocodiles or other big lizards so I think we can rule out reptiles and amphibians. Would you have the Ostrich?

As for the royal part, it reminds me of the wisent. The Czar had a herd of these bovines, the Bolsheviks said he loved them more than he loved the people, so as they were getting control of Russia they went and shot them all. So a royal 'O' might be some animal under protection of the king. We'll remember Robin Hood who became an outlaw by shooting a royal deer.