In ground effect....
Here's a Cormorant in "ground effect" over the Haw River in North Carolina. Ground effect is an aviation term for being in a dense layer of air, close to the service, typically thought of as about half a wingspan from the surface. Inside this distance, the dense layer acts almost like a pillow, where the available lift dramatically increases, and you can fly, or glide with much less effort. You can see that the flying feathers of this birds right wing have just skimmed the surface.
In ground effect....
Here's a Cormorant in "ground effect" over the Haw River in North Carolina. Ground effect is an aviation term for being in a dense layer of air, close to the service, typically thought of as about half a wingspan from the surface. Inside this distance, the dense layer acts almost like a pillow, where the available lift dramatically increases, and you can fly, or glide with much less effort. You can see that the flying feathers of this birds right wing have just skimmed the surface.