Lightening darker areas? Or other suggestions

[Skyline On Fire]

I'm trying to make the white areas even, and the vignette even. Any suggestions on lightening the out of place darker areas etc...?

Any other advice welcome,

 

[Kerioak]

How about something like this - if you use Photoshop

create new layer
use curves to lighten original layer
select bird and mask it out
(I used curves to lighten that a bit as well and put the border in to make it easier for me)
There is probably an easy way to put a vignette in in PS but I used gradients and dragged them around the birds head from the corners and sides to try and match the colours at the bottom

 

[Skyline On Fire]

Thank you Christine, that looks excellent. I'll be attempting this myself.