Humans of Rome?

Here is a vignette from my recent visit to Rome.  Apparently swallows are a nuisance.  As a tourist I found them delightful as one evening at sunset, departing from St. Peter's to make my way back home, I stopped to gape and wonder at a massive swallow murmuration.  It was beautiful and a thrilling sight to behold. 

The story:

On my first evening, before dinner - perhaps 530 PM or so - I grabbed my camera and just went for a walk in the dark in the general direction of the Tiber. I knew that I wouldn't go too far as the Tiber would stop me.

My wander ended at Ponte Umberto I and as I neared it, I heard the most bizarre noises. It was dark and hard to see details.

I saw two guys on opposite sides of the street walking very slowly and as they reached a certain point they would pivot and walk in the other direction for a while, then pivot and walk back again. Almost as if they were making a sweep. They were both dressed in white gear from head to toe and were carrying what looked like very large bullhorns.

They were making the most god-awful noise. It sounded like a pig being slaughtered, or something. Very unsettling!

I thought it was either performance art or a political statement about the treatment of animals/meat eaters. It really did sound like an animal being killed.

I was busy taking night street-photos when one came near me, still walking slowly and he didn't break his pace. I hailed him, and asked him what he was doing.

As it turned out, they are swallow control guys! The noise apparently is a distress signal only *very* loud. These guys walk up and down various streets for an hour making these noises! The swallows take the hint that they are not wanted and go elsewhere (maybe to do a murmuration over Vatican City).

I guess Romans don't like caca on their cars!

Here is his photo: