As I live on a mountain lake, I've photographed scores of bird species from my bedroom over the years. Usually I shoot through a sliding glass door in the winter as it's too cold to open any windows or doors. These images were all shot through a sliding glass door with a 20mm extension tube, tripod/ ball head. The tube reduces the 500 f4 mfd down to about 12 feet instead of it's normal 15 feet mfd. I'm 3 feet away from the glass on the inside, the perches are taped to deck balusters about 10 feet beyond the door where I can move them very easily to change the BGD or shooting angle. I prefer to shoot at a 45 degree angle through the glass which helps to eliminate glare from light sources behind me, namely other windows. I had over two dozen pine siskins and a single common redpoll for several days straight which was a highlight. Sorry, but the perches are all the same. Some in snow, some in better light.
Man Herb...you got some great glass....windows! It does go to show just how diverse the bird life in our own backyard can be and with a little bit of observation no telling what we'll see. I actually find having the same perch for all these really interesting....I wonder if your Coopers does as well
Eric
Amazingly good, and through a glass window no less. The male Cardinal stands out for me, but that wonderful shot of the Chickadee is my absolute favorite. That one really stands out. You are certainly making the most of your opportunities.
Sorry, but the perches are all the same. Some in snow, some in better light. 
The cardinals in 5 and 7 are my picks of the set. 
I'd be happy with any of these, but 1 and both cards stand out ~ Ron