But nothing quite as frightening as finding three rats one evening zipping around in my kitchen, ripping apart ketchup packets. Or the time my downstairs neighbors had an angry rat trapped in their kitchen (which was disposed of with a hockey stick).
I called the NYC Health Department hotline maybe 5-6 times. At that time, calling the number led to a voice mail menu, and the first options was "if you would like to report a rat infestation, press 1". This is no joke, some buildings were really and truly infested.
The city did nothing but to place poison rat traps on the streets. Only once did someone respond and come to our building, he just suggested that we fill up all known holes in our building with steel wool. The local hardware store had bulk packages of the stuff for sale, a popular item.
Our Chinese landlord solved the problem by calling a neighborhood expert. He brought his gigantic cat, who lived downstairs in the basement for several weeks. After that, we had no more rat problems for a long time.
There's an interesting business opportunity! Rent-a-Cat, or if you want something more distributed, an online service that allows people to lend cats to one another :)
As I continued to walk, now directly between the garbage and the empty lot, a huge pack of rats maybe 40 or 50 strong streamed out of the trash bag, deflating it completely. They ran over my feet up my legs, and then down again, disappearing into the lot.
I was young and drunk so it didn't bother me all that much but it was pretty nasty in retrospect.
I wonder why the cat population doesn't swell and match the rat population.
This map is great in terms of personal use. "Are there rat reports near where I live?". But would be great to see someone hack together a heat-map or something that better displays density.
Edit: Here's a quick stab: http://jsbin.com/dihiwetoja/2/
Just shade each of your already defined regions by [sightings/area].
A friend who makes a very decent income as a pest controller has very interesting stories to tell about the size of the rat population he encounters, the shift in their diet over the years (more fat and junk food remains), and worryingly, their increasing resistance to the wide range of controls in use today.