Common yellow-throat warbler:
Common yellow-throat warbler by
dcstep, on Flickr
My 500mm f/4 always has smooth bokeh, but I particularly like the green background here caused by shooting in the deep woods. That's cottonwood fuzz around the bird and on the leaves that are in focus. I used the tripod and gimbal to shoot at 1/80th second, f8 and ISO 200 to get all the detail that you can see if you link to the Large or Original size over at Flickr.
I considered using another bokeh shot because bokeh is such a common technique in wild bird photography, but then I thought that just because it's common doesn't make it any less good.
Dave