This Turkey Vulture (Cathartes aura) made three low passes over the fenced Burrowing Owl area. Twice it descended as if it had spotted something in the southern end of the area, but both times rose again without settling. The birds have a famous sense of smell for carrion. However, there was a stiff breeze, which incidentally ruined the sound track of the video, and it would have been a miracle to locate carrion in that breeze by smell alone. The wind, however, saved the bird energy in flying; it made its entire survey of the area with only two flaps of its wings. The turkey vulture is a most excellent and economical flier. At one point toward the end of the video, a white bird flies overhead and seems to attack the vulture, forcing it lower. I could not tell whether the white bird was a raptor such as a kite or a harrier, or some kind of gull, but my guess, based on very blurry enlargement, is gull. The gulls also feed on carrion and may have seen the vulture as competition.
Read other posts about the Turkey Vulture here.