Several images, please scroll down.
These birds are very common in California and it is unusual to be anywhere away from major metropolitan areas without seeing one or several of them soaring on thermals, the rising columns of warm air that permit them to fly for long periods with no effort at all. To remain within a thermal, the bird must fly in a circular pattern, so graceful banking maneuvers are standard. They are a glorious sight flying. On the ground, especially when eating their standard diet of road kill and other carrion, they are not so attractive. They are large birds; adults measure 26 - 32 inches long with wingspans of 68 - 72 inches. Hunts for food by sight and smell (vultures have an unusually acute sense of smell for birds, well adapted to finding carrion). The featherless head is a bright red; only a hint of that can be seen here.
This image was taken in my backyard in San Rafael, California, with a newly acquired Canon 70-200 mm f/2.8L IS zoom lens on the Canon 10D digital camera. The ISO speed setting was 100 and autofocus and image stabilization were both active.
Here's another shot with the digital camera, taken at Pt Reyes National Seashore on 31 January 2004. Bright sunlight picked up the red of the bird's head.
And finally, an image captured on April 1, 2005, in Marin County, with a 100-400 mm zoom at 400 mm focal length: