Sweet. Great calling pose, and beautiful bg and perch. Square crop works OK for me. Maybe just a tiny bit oversharpened on my screen, and I might be tempted to remove the one stray hair across the lower mandible. Still, I'd love to have this one in my warbler files.
I agree with removing the small strand across the lower mandible and a vertical presentation. Beautiufl BG, great perch (although the small extra bit at bottom should go if you keep this square composition). Audio?