I take your point but when you see 13 buzzards circling a field you don't hold out much hope for the red-legged partridge sitting in it.
Well, for one thing, the red-legged partridge isn't a native species; they were brought in to be hunted and some have now become naturalised.
I'd be more worried if it were grey-legged partridge.
However, living as I used to do on Exmoor, in amongst big partridge and pheasant shooting estates, with plentiful buzzards, from what I saw, I don't think buzzards represent a great threat to the partridges.
They mostly took rodents, as far as I could see.
Men - and women - with guns, however....