Do You Know What to Do With an Injured Bird?

I came home from work to find a fledgling blue jay in our front yard. When I approached he slowly hobbled away, but not far. I was not sure if he was just too young to fly or if he was injured. There was an adult bird squawking at me as I approached the little guy, so I originally figured the parent was keeping an eye on the fledgling and he would be okay.
A little later I came out and checked on him again, and he was still in the same place. So I gave him a few bird seeds. I do believe he ate a few. It looked as if he had broken a leg or something. He did not seem okay.
I checked on him several times. As the night went on, he tried less to move away from me, as if he just did not have it in him anymore. I checked on him one last time before we went to bed and the poor guy was lying on his side. I was heartbroken. I had a difficult time sleeping as I feared he would not make it through the night.
The next morning I was happy to see him sitting up again. This time there was no parent in the trees squawking at me. I did some research and figured out this bird was not okay and he needed help. Apparently it is not normal for a bird, even as a fledgling, to allow you come near and they do not sleep on their side. Not to mention it was mid-90’s outside.
I first called the Wildlife Rehabilitation Clinic in High Ridge, however they said they did not handle birds and directed me to the Wild Bird Rehabilitation in Overland. I called them up and asked them a few more questions. They were not able to pick up the bird, since they have limited resources and volunteers. I took a shoebox and went outside and scooped up the bird using the lid. I knew better than to touch the blue jay, as many birds carry diseases. He tried to fight me, but he did not have a lot of energy.
I took him to the Wild Bird Rehabilitation; they immediately grabbed him and filled him with several cc’s of fluid. They said he was not doing very well. He did not have a broken leg, but all of his tail feathers were broken. The fledgling had suffered some type of trauma.
I made a donation to the Wild Bird Rehabilitation (as they are a nonprofit) and picked up a volunteer orientation schedule. I was really impressed with their help and love for birds. I just hope they were able to help my little Blue Jay.