For a while the Robin, while waiting to be served, made a contribution of his own as if to show the newcomers that the residents are not so easily eclipsed.
Perched higher up the Blackcap politely paused then started again.
It's easy to tell Blackcap from Garden Warbler when you're lucky enough to see them. As the days go on trees become less open and more leafy so there's less chance of that. The songs of these two virtuoso warblers are remarkably similar. My own rule of thumb for identifictaion is simply that the Blackcap's phrases tend to be shorter - most of the time.