Nearly 1.000.000 feral cats in Sicily?
How many feral cats do really live in Sicily?

We suppose there are at least 338.800 feral cats in Sicily and 3.890.000 feral cats in Italy without any care on the streets.

There is no common formula to identify concrete numbers of feral cats, formulas vary between organisation and scientist. Moreover, factors like clime, geography and access to food must be considered.
As general rule exists this formula:
number of inhabitants / 3,5 = number of pet cats
number of inhabitants/     6 = number of feral cats

Some estimation takes number of inhabitants / 15 = number of feral cats

There are more feral cats in Mediterranean regions than in the colder regions.  You will find much more feral cats in the South of Italy as in the north. Due to climate change, population of feral cats are growing all over the world. Because the global warming provides prolonged times for pregnancies. In general, a female cat has two litters of kittens per year. But in some regions, they now have up to three times per year.

Around barns, parks, ruins, and touristic centers at the seaside there are many feral cats. You will not see all during the day. But in the night, there are a lot of them, especially the very shy and the noticeably young cats. They come out of their hiding places and search for food in courtyards and rubbish.  Keep in mind, cats are active at night. Usually, their condition is bad. They suffer from unhealthy food, untreated injuries, and parasites. They have no vaccination and are not neutered. Their average life expectance is 1,5 years. This must change!