I'd taken Barney on a ratting expedition down to the sheds by an old sugar beet stand and as I stood watching him hunting fruitlessly I noticed how much the ivy had spread. Already pushing up onto the roof of the shed you wonder where it comes from and I think it must be the birds. The pigeons and blackbirds are always feasting on the berries, particularly in this icy cold weather They take their fill of the fruit and they obviously digest the pulp and the seeds must pass down, through the digestive system and out complete with fresh guano to get the cycle going again.
I'm quite sure that if you dossed down in the tumbledown sheds with the ivy you'd be dragged down into the roots by the morning never to be found.
Ivy and ants they'll take over the world one day.