feral cats in Rome

I've been reading a new and very, very interesting book, The Inner Life of Cats, by Thomas McNamee. One chapter treats the feral cat issue, particularly in Rome, with more than 100 cat colonies; in one colony called Largo Argentina the population density was equivalent to 38,000 cats per square mile. 

"But studies have shown that where food is abundant, cats develop completely new systems of sociality that can allow for high density. Picture how New Yorkers and Parisians preserve their dignity on a crowded subway car."

In 1988 the Roman authorities forbade euthanasia of any cat or dog except those incurably ill or fatally injured, and in 1991 the Italian Parliament proclaimed that feral cats had a right to live free and couldn't be moved from their colony. 

There is a metro station in the city called Piramide (pyramid)  and "Adjacent to the Pyramid is their nighttime prowling ground, the leafy, cool Protestant Cemetery, where John Keats and Percy Bysshe Shelley are buried...Many of the monuments are fancifully ornate examples of the gravestone-maker's art, and the whole place is impeccably kept. Somebody, doubtless from the gattare (local cat lovers who leave food, and watch out for them, etc.), evidently picks up the cat poop, because there's none to be seen... Someone - the city of Rome? the volunteers? - has hidden audio somewhere in the ruins, so that at night the cats have classical music playing for them." (emphasis mine)