The above pic is with the new 500mm F4 II lens. I am not sure, but I can swear that since I changed from the older 500 mm IS lens I am able to push the ISO a little higher with the 7-D. I personally think it is because the lens is producing a much sharper image to work with to begin with. Regardless I am just really impressed with the new 500 II lens. It is a worthy successor for sure.
I'm no expert at post processing. I like the KISS
( keep it simple stupid ) principle. :) I don't use any external de-noise software and really do not think it is necessary. I use PS-5 and it takes me about 10-30 seconds to de-noise my photos. I do isolate the bird and perch. And de-noise the background. For me it is simple and effective. And fairly fast. Since I use, and like the 7-D my post processing takes a little more time than some other cameras. I think anyway. PS-5 is all I use. I convert my RAW in PS-5 and finish my processing there as well.
I really like the on line book from "Third bird from the sun". Google it. It is a free online book. I personally think it is the best for this kind of work. Many people try and sell there books for post processing and birding. But it really is easy and fun. And fun to learn.
Just kick back and enjoy the hobby. There are many very good birders out there that just want to have fun. That really enjoy helping and contributing to the hobby. Without hidden agendas. I think anyway....
Birding is free and enjoyable. Go out and enjoy. Take a pic? Buy some binoculars. Or grab your old binoculars. Get your DSLR or point and shoot and take a few pics of birds. It may grow on you.