Pretty much every evening before dusk in Wargrave on Thames huge flocks of large black birds wheel and swoop gathering every so often in tall trees. Best guess approx 1000 birds. All the time chattering.I would love to know what type,are they rooks or jackdaws ? They are remarkable.
Hopefully someone more local to you will reply, but I suspect jackdaws. Rooks would be breeding now....unless they've been disturbed/had rookeries destroyed etc.....so could be either now I've written that!