Looking at the photo's histogrma shows a good exposure .
But I understand you did some pps and lightened it up .
So I assume the original was quite dark .
I am a great spot metering enthusiast - and when metering, my main goal in getting the histogram as far Right as possible . In your case - I would meter from the bird , aiming at about -1/3 ( dark bird ) , not worrying about the sky . If you need high shutter speed - crank up the Iso , or open aperture , but keep the exposure correct .
If you use evalutive metering when shooting a dark bird against the sky - you'll always end up with a too dark bird . That is why I almost always use spot metering - I want my SUBJECT to be exposed correctly . It true for dark birds on bright skies , and white birds on dark BG.
When shooting a bird in a bush , or some other multicolor environment - then I use evaluative metering .
here's an example: