There are sample sounds out there on the web. Not owning a high-speed device like an i-anything, I would not know how to up/download.
However, if your intent is to use it for hunting, I'm guessing you will need more volume. There has been some discussion by a couple of guys thinking of amplifying the iPhone's output using external speakers, but by the time one is done fooling around with all the gear and taping it together, it would be more cost/time-effective perhaps to purchase a used FoxPro Spitfire and work your way up. Heck, there's guys out there who are still using 45 rpm crow calls on a portable battery-powered record player!
__________________
"Arms are the only true badges of liberty. The possession of arms is the distinction of a free man from a slave." -- Andrew Fletcher 1698
Get yourself an ICOTECH GC500, 1/3 of the price of the other makes, fantastic quality, and you can add up to 200 calls onto an SD card. 15 watt speaker, LED backlit display on the remote, 300 yard remote range (the guy who makes them used to work for one of the better known companies). Also a jack for a remote speaker, and a jack for a remote decoy which they will have for sale from August this year :)
I have one and use it for fox control, as electronic calls aren't allowed over here for hunting birds
__________________
If it moves and is legal but also moral, SHOOT IT !!