Although they look like ducks and act like ducks, pied-billed grebes, according to DNA studies, are more closely related to flamingos than ducks. I was surprised to learn that, as well as a couple other interesting items.
Pied-billed grebes (Podilymbus podiceps) have been called “little submarines”. They can “crash dive” straight down, swim just under the surface, swim at the bottom and submerge “alligator style” and float with their eyes just above the surface. This is because they can alter their inherent buoyancy by squeezing trapped air out from between their feathers and internal air sacs. Each pied-billed grebe feather is attached to the skin at a right angle with a curl at the top trapping air against the body. By modifying the way the feathers lay against the body the amount of trapped air changes adjusting buoyancy. Of course, removing air from around the body allows more water to get trapped in the feathers. Some authors contribute the buoyancy control by a pied-billed grebe to be due to water trapped in the feathers, but this is simply another way of looking at removing air from around the feathers.
Another fascinating thing is that pied-billed grebes eat their own feathers. This is believed to serve two purposes. One is that the feathers act as a sieve in the stomach and keep harmful, sharp prey parts from entering the intestines. Secondly, the feathers encapsulate indigestible matter so it can be disgorged as pellets, similar to an owl’s casts.
This cute pied-billed grebe was swimming in Ash Creek near the Hall Pond Trail in Ash Creek Wildlife Area near Lookout CA (Modoc County). Years ago I wrote another post with more information about pied-billed grebes (02-11-2012).