Nginx and uwsgi; different ports

I have Nginx and two python virtual environments with uwsgi. These environments are for dev and production. What I want is to run production on :80 and dev on :6544 ports

Here's the config I have

server {
    listen          80;
    access_log      off;
    error_log       /var/log/nginx/http.prod.error.log;

    charset         utf-8;
    location / {
        uwsgi_pass  unix:///tmp/uwsgi.sock;
        include     uwsgi_params;
    }

}    

server {
    listen          6544;
    access_log      off;
    error_log       /var/log/nginx/http.dev.error.log;

    charset         utf-8;
    location / {
        uwsgi_pass  unix:///tmp/uwsgi.sock;
        include     uwsgi_params;
    }

}

When I do %production%/bin/uwsgi --ini-paste-logged %production%/production.ini
it runs well. But when I'm trying to start dev version %dev%/bin/uwsgi --ini-paste-logged %dev%/dev.ini I got the next in the uwsgi.log:

*** Starting uWSGI 1.9.12 (64bit) on [Fri Jun  7 07:35:21 2013] ***
compiled with version: 4.4.3 on 07 June 2013 07:32:32
os: Linux-2.6.32-38-server #83-Ubuntu SMP Wed Jan 4 11:26:59 UTC 2012
nodename: pt-apps2
machine: x86_64
clock source: unix
pcre jit disabled
detected number of CPU cores: 24
current working directory: /home/dev
writing pidfile to ./pid_5000.pid
detected binary path: /home/dev/bin/uwsgi
your memory page size is 4096 bytes
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
unlink(): Operation not permitted [core/socket.c line 135]
bind(): Address already in use [core/socket.c line 185]
*** Starting uWSGI 1.9.12 (64bit) on [Fri Jun  7 07:38:24 2013] ***
compiled with version: 4.4.3 on 07 June 2013 07:32:32
os: Linux-2.6.32-38-server #83-Ubuntu SMP Wed Jan 4 11:26:59 UTC 2012
nodename: pt-apps2
machine: x86_64
clock source: unix
pcre jit disabled
detected number of CPU cores: 24
current working directory: /home/dev
writing pidfile to ./pid_5000.pid
detected binary path: /home/dev/bin/uwsgi
your memory page size is 4096 bytes
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
unlink(): Operation not permitted [core/socket.c line 135]
bind(): Address already in use [core/socket.c line 185]

dev.ini contains the next settings:

[uwsgi]
socket = /tmp/uwsgi.sock
master = true

processes = 4

harakiri = 60
harakiri-verbose = true
limit-post = 65536
post-buffering = 8192

daemonize = ./uwsgi.log
pidfile = ./pid_5000.pid

listen = 256

max-requests = 1000

reload-on-as = 128
reload-on-rss = 96
no-orphans = true

log-slow = true

I believe I did something wrong with the config, but I have no idea what is wrong.
Another interesting stuff, when production UWSGI is running, I can access to :6544 but I don't see dev version there, only production. So I think that 80 and 6544 ports are used for production only. Any idea how I can split two versions of one app by the ports?

Thanks