These photos were taken on August 13th of this year in the early afternoon. Our summer had been mostly hot and dry.
My vantage point had been a second story window. At first when I had glanced out and had seen the juvenile robin collapsed on the ground, I thought the poor thing had suffered an injury.
(please click on images for better viewing)
After a short time had passed though, the robin folded its wings together and calmly hopped away.
I discovered several articles that described this "sunning"* phenomenon in the wild bird population. The birds will flop down, often leaning to one side, spread out their wings and tail feathers and remain motionless for several minutes. Notice, too, the raised position of one wing in the first photo.
*It is thought that this helps to "dislodge feather parasites".
The Earthlife Web