I learned today that the birds will seem to have disappeared at the moment because they are moulting. Certainly, I had noticed that they were less in evidence, so I decided it was time to lift the netting.
Well it may have been. At the same time, there was another reason for the currants looking a bit sorry for themselves: upon closer inspection, the new growth was being attacked by aphids (and ants). So, out came the neem oil, which I hope will be as effective on them as it has been on the apple tree.