When me and Bill were in South Dakota at a rest stop there were several birds like that...dying of thirst. It was way over 100 degrees and a hot wind blowing. Bill found a spot in the parking lot that was hollow from cars parking there in the heat, making a place where we could pour our cold bottled water out for them, and he carried them over to the water. They drank immediately.
Don't have to worry about that here...it's not hot, in the 80's, but humid, and raining for several days. But I always keep clean water in the bird bath and food for them.