Wing-spreading was more common when vultures were wet than when they were dry. Turkey Vultures appear to spread their wings for at least two reasons: (1) to dry feathers, and (2) to ameliorate the thermal gradient between themselves and their envi- ronment, although the two functions are not mutually exclusive
We kind of figured it wasn't for drying, but we couldn't figure out what it was doing. We never heard of them regulating with their environment by wing spreading. Thanks for sharing that info