Reply #8: if your tundra is in the United States...

[amazona]

...yes, it is a federal offense to shoot the owl. Period. End of sentence. People have been fined a great deal of money for killing them. Since ignorance of the law is no excuse if someone who doesn't like you or your activities reports you, it is best to be aware of the law.

Owls come in pairs, especially when nesting. They are not known to be able to reproduce by division, so I don't know why it is shocking that there are two of them. It sounds like you may have already harmed or killed the mate. Best not to share that information with law or game enforcement, since you can't undo what is done.

I have to repeat, contact Fish and Wildlife. Great Horned Owls are very powerful birds. They have caused serious injury. You don't want to be shooting a bird, injure it, then run out and try to "rescue" it, and end up losing an eye. It has happened with nesting owls and to persons with considerable more experience with owls than any of us here happen to possess. If you are in a hazardous situation with these birds, you need expert help in removing them.

Some problems can't be solved over the internet. You need an expert in wildlife control on the scene. Call Fish and Wildlife. And if the ranger is not in the office when you call, call back. If you are not safe with the owls where they are, then you need to get help with the project of removing them.

For future reference, ALL birds of prey are protected species in the United States.

The conservation movement is a breeding ground of communists
and other subversives. We intend to clean them out,
even if it means rounding up every birdwatcher in the country.
--John Mitchell, US Attorney General 1969-72