This might hurt.
The swarm was an amorphous blob suddenly striking with murderous force. Feathers and small squirming bodies digging viciously into the flesh of some rodent that had exited a storm drain. Its’ squeal of pain was short lived as the birds fought for the scraps of the meager meal. In a mater of moments they took flight again, settling back down amongst the fallen leaves and bits of detritus, black smudges against the autumnal browns. The animal they had ravaged was naught but a smear of blood and fluids, slowly seeping back into the sewer from which it emerged.
The birds cocked their heads, peering back at him with intelligence he neither noticed nor would have appreciated. He resumed his journey, stepping carefully now, having to stretch his stride awkwardly to avoid the more stubborn of the group. He almost made it past them.