First nature pics

i want to release some prints this year, i am not seasoned enough to feel comfortable with the term fine art, but i would like to enter some local art shows and possibly try to sell these.

these are my first real attempts at landscape/nature. my next goal is to shoot some secluded beaches.

please critique:

Looks pretty good. I like the color bird and the crocodile picture the best.
First 2 picture are good also.

it was a very overcast day, which worked for most pictures but the landscapes i feel could have benefited from a more contrasty sky.

The trees are interesting but the white sky ruins them for me. If the same images could be shot during the golden hour you may have better images.

The birds just don't pop out from the images enough.

And the gator(?) blends into the dark contrast of the image too much.

Overcast works well with portraits but not so much so with landscapes. If there are clouds you can change the whole image but your sky looks rather flat and gray.