I took the birder's direct route to the grocery store, via Smithville Lake (Clay County, MO) today. Intrigued about the possibility of the large grebes apparently moving on or becoming Eagle food. As posted by KM (thanks!), the 3 Aechmophorus grebes were seen about 12pm from the south end of the dam. They were way out in the middle of the lake, feeding actively and napping briefly in the midst of a small raft of ducks (moments like these make a strong case in favor of a high-end scope with the HD glass).
Regarding the molt of these birds and how this feather replacement affects their appearance, the Clark's Grebe is now noticeably lighter overall on the mantle, scapulars and wing coverts. The Clark's also appears whiter in the flank area. The Western Grebes appear darker in these areas. These differences were not apparent 2 weeks ago and can be seen with a critical eye at great distances (in good light). Of course, the bill color of the Clark's, when seen in decent light, still jumps out at you. To my eye, the CLGR is getting darker behind the eye, making the amount of light/dark on the face not as apparent as it was a couple of weeks ago. The white loral area of the CLGR still shows well at close range.
I left the north end of the dam about 2pm, with the CLGR in my scope at 20x, appearing and disappearing at will. Only one WEGR was observable at this time, waaay out on the main body of the lake. Good luck to everyone chasing this bird and drive safe.