Will there still be birds dining at Seanhenge? Most probably. 6700 years is nothing in the history of life. But we will all be deep in the long peace of the untroubled night (unless some unexpected surprises await us, like a slick tour operator saying "Did you enjoy that life-experience holiday? Do you want to book another one?). Goodnight.
I do like the idea of birds still calling this place "Seanhenge" in 6,700 years. The peace of another night.