just playing killdeer

I just got back from having lunch in the park across the street from my building. As I was leaving the park, I noticed a robin (Turdus migratorius) sitting on the wood chip mulch by the exit, not five feet away from me. Its right wing was half extended, and at first glance I thought it was dead, but as I approached I saw it turn its head a little. I stood for two or three minutes watching it breathe, thinking that it must be injured or poisoned. To my surprise, it abruptly folded its wing and scratched its neck with its right foot, hopped under a bush, and scratched some more.

Do robins sunbathe? because I can't think of anything else it might have been doing. Awfully tame not to run away from me, too.