I agree, I have shot at higher ISOs, but even your blue heron shows considerable luminance and color noise. BTW, using Capture One Pro Sony will mitigate most of that noise. This is what I used for the lower Manhattan set I posted the link to. One of the problems of using the Sony (or any other camera that does not do that well with noisy shadows), is that night shots, which have lots of dark areas, end up being very noisy.

Here is a test I did at 6400 ISO and though the uncropped image isn't completely horrible, it totally lacks detail and still has a lot of noise, and certainly isn't anything to write home about. I love my camera, but I do so in full appreciation of it's limitations.