If you find a wild bird - say, a house sparrow, how do you care for it?
I found a website that discusses how to provide warmth, food, hydration, and many other issues regarding how to care for a young sparrow. Check out the website: http://www.starlingtalk.com/babycare.htm.
Here's another website of a non-profit organization that deals specifically with rescuing wild birds: http://tinywingsinneed.us. They have provided me with a lot of information, answering my questions very patiently. You may email them at email@example.com.
It's very difficult for a wild bird to survive if it wasn't raised by its parents. Every young bird that comes to your care is a big challenge and a noble undertaking. You will need all the help you can get.