In the copse at the furthest end of the field roost hundreds of crows, a Murder of Crows.  They are sociable birds who live together in large numbers for protection from predators.  I have seen small groups of them flying around a buzzard to push the larger bird away – and winning.  So named at a time when other groups were called an Ostentation of Peacocks and a Parliament of Owls.  Maybe their silky black wings remind us of death and mourning or maybe so called because they feed partly on carion.  They are not a well loved bird and farmers try to keep them off their fields with, of course, a Scarecrow!