I wouldn't even bother with birds unless your harvesting something large like a Turkey. As for small critters like squirrel and rabbit there are numerous videos on Youtube that show you how to clean.
A recipe I like is once you've cleaned two squirrel quarter them out in large portions(shoulder and backstrap, hind legs). Soak them in salty water for a few hours to help take the gamey taste away. After soaking, lay out a section of aluminum foil and lay the squirrel meat in the center. Cut up a onion, drop the onion slices on top of the meat, Cut up a potato and do the same. Cut up a carrot in small circular sections and toss em in. Season with 2 tsp of salt, and as much pepper as you like. Also if you have season all or whatever other spices you like add them now. Roll the aluminum foil up like a burrito across the middle. Roll the end up to the center but not too tight. Set it aside.
Start a fire, I use simple pyramid or teepee design. Keep the fire going for about an hour or so. While waiting this hour make sure to feed the fire medium sized fuel wood(not tinder or kindling but the beefy wood that burns for a while) dig a hole about 12-18 inches down. After the hour has passed let the flames die down, rake half the coals and embers into the hole you just dug. Drop in your squirrel, make sure to keep if flat so you don't lose any juices. Cover the top of your squirrel with the rest of the coals. Finally fill in the hole with earth. Find something to do for 2 hours. Come back after 2 hours and dig up your supper.