That's one theory that is suggested in the article. Barred owls from from the east.
According to my “Birds of North America” book, the spotted owl is supposed to occupy a limited range in the California Sierras, also a fairly large area in the Colorado and New Mexico Rockies as well as up in Washington. The barred owl is supposed to be completely absent from those areas according to the book. So it would seem to me that the spotted owl, as a species, may not be in danger of complete extinction. Maybe more study should be put into those areas to help it survive, even if Washington loses out due to Nature taking its course.
But what is “the east”? The land bordering it to the east? Or the East Coast?