Starlings, it seems, are what i was seeing. I guess if you search Rome starlings on YouTube you can get some video, but here’s a NY Times photo gallery and story about them: http://www.nytimes.com/packages/html/magazine/20070422_BIRDS_FEATURE/index.html

and the BBC – estimates up to 5 million starlings…

http://news.bbc.co.uk/2/hi/europe/7755309.stm