Hi Otávio,
These are, as usual from yourself,
good shots.
In an effort to offer some 'helpful thoughts' - and I do appreciate that these might not have been possible for you at the time of shooting, but may help others when presented with similar opportunities.
#1 - Not a lot to improve this one; I can only suggest running a blur brush over the background, mainly to 'smear away' the noise rather than improve the bokeh, which is already perfectly acceptable.
#2 - I wondered about suggesting a slightly tighter crop, different composition, but I'm unsure - you probably have it right here, the normal guidance about giving it "space to look into", i.e. on the left, does not apply since the subject is obviously keeping an eye on you
#3 - If mine, I would have cloned out/spot healed that single, distant bubble on left, 'behind' its head/neck.
#4 - Being
very picky, I might have left another few pixels across the top edge
#5 - If you could have got a shot with the beak/bill not quite 'touching' the tree branch, it might have been better, but again I am being very picky mentioning it, sorry
#6 - this one I might have tried a crop placing the bird just a little more toward the top left corner, but not by much
If I had been posting these six images, I'd have done so in a different order; 1, 2, 4, 5, 3, 6.
I say that because it keeps the Cormorant's together and I found the bright #6 a heck of a 'jolt to the eyes' after #5, whereas following #3, this would be diminished.
Anyway, I hope those thoughts are of help to someone, but agreeing with me is not mandatory
I can't decide on a single favourite, I do particularly like the Black-bellied whistling duck, #2 - an unusual angle you have 'pulled off' and #6; the Snowy Egret.
Well done, Dave