Telltail sign

I think I can say these feathers were not cast aside idly by a bird by way of normal moulting. Methinks the bird is dead, a victim of a deadly assassin. From time to time a raptor uses our garden as it's dining room. It raids next door's bird table but brings the kill into our garden to pluck and devour. I quite expect to find future kills in the same area soon; that has been what has happened before. We regularly see sparrowhawks and kestrels, and occasionally a peregrine, but I have no way of telling which was the perpetrator on this occasion.