Where can I find the error logs of nginx, using FastCGI and Django?

Errors are stored in the nginx log file. You can specify it in the root of the nginx configuration file:

error_log  /var/log/nginx/nginx_error.log  warn;

On Mac OS X with Homebrew, the log file was found by default at the following location:

/usr/local/var/log/nginx

I was looking for a different solution.

Error logs, by default, before any configuration is set, on my system (x86 Arch Linux), was found in:

/var/log/nginx/error.log