I shot this singing Savannah Sparrow from my car, resting the setup on the door frame with the window down, with a Canon 1D Mark III, a Canon 600mm f/4.0 lens, and a 1.4x Canon II teleconverter. The ISO was 400, the shutter speed was 1/250, the aperture was f/11.0, and an EV of -0.33. I chose the relatively small aperture because I wanted to make certain that the entire bird was in focus. I was not concerned about the background as it was a distant, uniformly green meadow. The image is cropped and I cleaned up the rather heavy droppings on the fence post.
I like the singing pose. Wish you had a better perch...but as is I think more room below to include the complete perch surface at bottom plus a bit more would be better. I realize it is not a big crop, but the "coarse" details make it seem so.