I was reading that it is illegal to capture a mourning dove...they are Federally protected and thus I would call a wildlife rehabilitation expert.
http://www.fws.gov/migratorybirds/
scroll to about halfway down the page..."what do you do if you find an injured..." and it gives a link to find an expert.
It is a bit late tonight but yes, your best bet is contacting some type of rehabilitator of wild birds. You can try calling local vets to see if they have contact information.
The photo suggests that has suffered some sort of trauma (maybe a predator?) and is in shock or otherwise not doing very well. If it had a tangle with a predator such as a cat then it would need antibiotics administered by a rehabber right away as otherwise they can succumb very quickly to infection. Poor critter. I hope it does not suffer.