In reply to toad:
All deer have increased since I was a teenager.
One of the problems for Scotland is that Red Deer are generally woodland animals but in Scotland they are largely restricted to areas of poor hill land, one of the results being they prevent the regeneration of natural forest - as the article mentions. But the estates do not want the deer gone completely -after all they don't sell the stalking cheaply!
And then we';ve got the 'bunny huggers' who don't like anything being shot/killed or culled for any reason.
One thing did occur to me when I looked at the hundreds of deer coming in off the mountain in snow is that if they replaced the Red Deer with Caribou/Reindeer, I assume they'd be quite happy to live on the Scottish mountains and they could still be shot/income for estates.