Lovely zoo pics. Mine from the zoo in Emmen (also Netherlands, provided you are talking about the Amsterdam in the Netherlands, rallyxe) can't compete with any of these.
With some you did some creative cropping, right? You cannot have got that close to the elephant baby. I did not to the one in Emmen, either - plus I did not have a useful telephoto lens on me. Hmph.
I'm fascinated by the close-ups that are so very crisp, such as the giraffe or the bird.
But they are all very nice.