I stepped down because of proximity of subject, in retrospect maybe I should have shot at wide open? This is a quick grab shot, didn't have time to get a lower angle. NR on background, Smart sharpening on bird, added a vignetting because of bright surroundings.
EF 500mm + 1.4tc, Tripod, Aperture Priority
Camera Canon EOS 7D
Exposure 0.001 sec (1/1250)
Aperture f/9.0
Focal Length 700 mm
ISO Speed 640
Exposure Bias +1/3 EV
Nice juxtaposition of the bird and the plant, but for me the background is distracting, and the Sparrow, particularly the face, is a little soft. The sharpest part of the image is the Foxtail.
Interesting and effective composition. I like the seed in the bird's beak. A lower angle would have helped, but I see that you didn't have time. I would have opened up. I would consider removing the OOF green patch in the foreground. I'm not crazy about the vignetting.