
Edited using Darktable, GIMP and Adobe Lightroom Mobile (free)
This was a very challenging photo to take.
Shot on Nikon D5100 with a 70-300mm non-VR lens I bought on resale (autofocus does not work). Sunbirds are comparable in size to Hummingbirds, only slightly larger. Getting the focus right was a moment of pure joy.
As for editing, very minimal editing was done in Darktable. Some local contrast on the bird and color boost on the iridescent feathers.
There were a couple of blurry branches in the foreground, removed them with GIMP.
All these were done on a laptop with a very bland and inaccurate LCD panel. The final tweaks were done using Adobe Lightroom Mobile. The amoled on my phone gives a much better idea of what to tweak. Added a slight vignette with heavy feathering to draw the eye on the bird.
Exif: 1/1250 | f/5/6 | 300mm (450mm equiv on APS-C) | ISO 400
Will add in camera JPEG for comparison in the comments.