From Len Nelson:
When I took an image of a Turkey Vulture (TV) on 6-22-18 in Ellis Creek, I only did so because it was nicely backlit on a post with its wings open. But, when I proceeded the image in PhotoShop and expanded its size, I clearly saw that the TV was in a literal cloud of Midges*. These little flying insects are often mistaken for mosquitoes but for the most part are harmless. For the local swallows though, they are food.
*Midges are a group of insects that include many kinds of small flies. They are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. The term “midge” does not define any particular taxonomic group, but includes species in several families of Nematoceran Diptera.