Birds Shouldn't Smoke

Birds actually breath differently than mammals. In mammals we have a diaphragm that pulls air into the lungs, we then expel it. Birds do not have a diaphragm, in order to breath they expand their chest, opening their air sacs which in turn fill with air; they must push the air out as well. Nor do birds have alveoli (small sacs in our lungs that get clogged with tar), but rather tubes in the long walls that take in the oxygen must faster (meaning smoking is much harder on birds).

This whole system is much more efficient than the mammal approach and its probably what killed them (the dinosaurs that is, them being birds) off after the meteor hit...not the fire ball, but the pollution (that is my surmise by the by).