A couple of days back I found a few feathers on the ground suggesting a young Greenfinch had fallen victim to a Cat but all the birds kept coming as per usual so I thought no more of it. This afternoon a Lesser Blackbacked Gull was swooping around quite low over the garden but the few birds that had showed up completely ignored it.
I have only one other theory and that is that I have a Sparrowhawk patrolling my patch again after an absence of 18 months