I think these could be great shots, but what spoils it for me is the haloing around the bird, it feels like you've gone crazy with the clarity slider in lightroom. Also looks like they've been desaturated. I have the older version of your tamron so it is always good to see photos from the g2.
Ya I noticed that after PP as well. I definitely do not like the haloing either. These were editied on my mobile since I'm travelling right now. They were a bit underexposed which is why some of them look desaturated like you said.
Just looked at some of your settings. Your problem is that your are using a ridiculously high aperture. The last three was f25. Any reason you are using such a high aperture? You should be almost wide open. I agree with @Coull3d that these could have been great shots. The captures are very good.