Well done to you for putting yourself out to help, its all too easy to just drive past.
My friend found a small deer (not sure which type probably Muntjack) curled up in the middle of the lane, got out of her car and picked it up and put it at the side of the road where it promptly lay down again. After stopping the traffic and a couple more attempts, she assumed it had been struck a glansing blow by a passing car and put it in the back of her car (with her two daughters!) and took it to the local vet.
There were no visible injuries and seemed quite alert and unfazed by the car journey. However on calling later that day to enquire she discovered they had immediately put the poor thing to sleep because they were not able to take it anywhere.
Sounds like your bird is having better look.