Hi Marius,
One of the important skills in becoming a photographer is learning how to crop an image.
More experienced photographers usually learn to crop in camera. That is, they either zoom the lens or they change their proximity to the subject until they know the space within the frame is being well utilised.
There are instances though, when cropping has to be done in post-production, and this is one of those times.
The actual framing of this pelican, top to bottom, is quite good but because of the 2:3 ratio of the format we discover there is quite a lot of blue to the left and right of the picture. In my opinion this water is contributing much to the photograph so I would be tempted to crop the picture to square.
All I would do then is open the curves panel and shift the middle of the curve outwards a small amount to lighten the mid tones and I think you are in business.
Cheers,
Anthony
Image Doctor's edited version