An Interesting Question

It was probably taken from any of those CD's with stock sounds.
Sounds from the city, sounds from nature, animal sounds e.t.c.

I'd assume that this is most probably the likely answer (though I have nothing to back it up, other than that after years of working in a recording studio, it was always much easier to get a pre-recorded sound effect on CD or off the internet, as it is just a hassle to go and do a field recording - for one thing you have to bank on it raining).