Spotted this robin displaying some unusual behavior--my first thought was dust bath, but I'd thought it'd be worthwhile to get a second opinion. Regardless, it's a quirky little snapshot! Never know what you find on here.
I have seen many kinds of bird spread their wings, both over dusty spots but also over dewy green grass. One theory is that they do this to dust or wash off mites and other parasites. Another is that they are cooling off or drying off. There are probably other theories as well.