unknown object seen later on a DSLR photo

object was noted later that evening as we downloaded photos taken to a computer. Nothing was seen during the taking of the photograph. We were on a hike around an urban wildlife refuge park in Tucson with a group of approximately 20 people. No one reported seeing or hearing anything at the time the photo was taken. East is to the right, west is to the left. Brighter area of the object would probably been in line with the sun. Thin clouds, 80 degrees, light to calm winds.