A multitude of buzzards

Several times recently, including today, I have seen no less than 9 buzzards together on a field near Merthyr Mawr. The field is down to Oilseed Rape, but rabbits have taken much of the crop , leaving several acres of bare earth. There are many worm casts on the soil surface, and I assume that the buzzards are after worms – the birds are spread out across the field. Several of them are immature, so presumably a family group (or several families?) A few weeks ago there was a Merlin on the field, presumably doing the same thing.