[Saphire]

Fabulous shots Roy, I never bother anymore about making sure I am square to the windows, if I see a shot I take it. If there is any loss in quality its usually to do with the contrast and this can be corrected on the PC.
You can get a little bit of loss like you see on the eye of your first photo but usually that's because of to acute an angle to the glass, on yours I think the hawk moved its head just at the wrong moment rather than the window angle.