eared grebe
Podiceps nigricollis

For a moment, I thought this might be a horned grebe (Podiceps auritus). I find the seasonal changes of plumage to be challenging for IDs, especially since I know so little about birds in general. Based on Cornell's Lab of Ornithology (linked in the scientific names above), this eared grebe may likely be in the process of changing into its breeding plumage and the horned grebe is only in our area in its winter black and white form. I'm left with a question: what constitutes summer or winter, when we have "summer" flowers blooming here in late winter/early spring?

As side notes - I have trouble IDing grebes in particular. In fact, before researching last year's May 10, 2009 grunion greeting post, I never heard of a grebe before. I've found Cornell's site to be my favorite resource for bird IDs. Plus, they were very kind in replying to my query about rights to linking to their site.

ps 05/20/10 - I'm amused even experienced birders get these mixed up. Don Roberson spells out the differences between eared and horned grebes on his creagus site.