I think this might be a caracara. One of the difficult things with doing this kind of photography is that, because of the movement of the boat, you have to shoot at a high shutter speed. Since the animals are moving, you need a small aperture to increase the depth of field. This helps keep it in focus if it moves too quickly as you focus. However, to shoot at high speed and small aperture, you have to boost the ISO level to where it’s unacceptably sharp … or deliberately underexpose. Underexposing works well, but when you bring it back up to being bright enough to see things, the colours are off.

So you switch to black and white.