dnsmasq won't start

[Patrick O'Callaghan]

For some reason I'm getting this:

$ systemctl status dnsmasq
● dnsmasq.service - DNS caching server.
   Loaded: loaded (/usr/lib/systemd/system/dnsmasq.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Mon 2016-01-25 13:27:16 GMT; 1s ago
  Process: 3502 ExecStart=/usr/sbin/dnsmasq -k (code=exited, status=2)
 Main PID: 3502 (code=exited, status=2)

Jan 25 13:27:16 bree systemd[1]: Started DNS caching server..
Jan 25 13:27:16 bree systemd[1]: Starting DNS caching server....
Jan 25 13:27:16 bree dnsmasq[3502]: dnsmasq: failed to create listening socket for port 53: Address already in use
Jan 25 13:27:16 bree dnsmasq[3502]: failed to create listening socket for port 53: Address already in use
Jan 25 13:27:16 bree systemd[1]: dnsmasq.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
Jan 25 13:27:16 bree systemd[1]: dnsmasq.service: Unit entered failed state.
Jan 25 13:27:16 bree systemd[1]: dnsmasq.service: Failed with result 'exit-code'.

Can't figure out what is sitting on port 53 (the DNS port). I'm not
running bind.

poc