Squirrel Control - Do Owls sometimes nest in old squirrel dreys?

I need to control the squirrels in some woodland as they are decimating the younger trees.

Apparently poking or shooting the dreys at this time of year is a very effective control method, but have also heard that Owls (or other birds) might sometimes start using an old squirrel drey to nest in. Is this true?

Obviously I don't want to harm anything other than squirrels!