Border Control: no this has nothing to do with Mexico! When you take an image, it is easy to capture extra 'stuff' that is not part of the image that you want and it make take away from your subject.
In the first image, there is a little too much going on. There are extra ducks and a leave floating that take away from the subjects (which were the yellow and the brownish ducklings). By cropping and cleaning the image just a bit, it changes it and leads the eye to focus on the two subjects.