Cleaning up in the garden 2 days ago, what a surprise. I knew they nested in unusual places but, a nest inside a black potato grow bag.
Was it a Robins nest I thought it was.Was it a old last years nest? No. This years.
Checked today 2 eggs pinkish colour. A Robin I think. Problem. Bag is only 2-3 foot off ground level on top of a plastic dustbin I use for compost bin. Plenty of cats in neighbourhood. Should I put some netting around before mother sits.
Any change around the nest could cause the bird to abandon the nest but it sounds like there is a good chance any chicks would be taken by cats. Wire mesh with about 2 inch holes would keep the cats off and allow the birds through.
If you move it higher try and do it in short steps.
I agree wren's eggs are mottled pinkish and the position of the nest would fit. You would need to set any protection about 3-4 foot from the nest to allow the parents to come and go easily. I would just put thorny branches all round should deter cats and being natural won't bother the birds.
Update. Noticed whilst parents were away gathering food. At least one chick hatched. But after checking at least a week and half later, nest empty. Gutted. Predated by Magpies, Crows, squirrels.??