Thanks to everyone for the bird lung diagrams. I too could not believe I had never known how birds lungs worked when I discovered it at age 48 while homeschooling my daughter for one year. I told everyone I met how they breath.
Also, as for dinosaurs eating coniferous trees, it's not hard to imagine they did. We have wallabies, and I can't feed them Doug Fir fast enough. Goats and sheep will also happily eat the needles, and the bark. The new Doug Fir growth is packed with vitamin C, and is great in smoothies, or to eat straight. It is also a wonderful breath freshener (for Wallabies, sheep and humans alike!)