 there are many distinct differences ( morphologic , physiologic , and mechanical ) between the bird 's lung - air - sac respiratory system and the mammalian bronchoalveolar lung . in this paper , we review the physiology of the avian respiratory system with attention to those mechanisms that may lead to significantly different results , relative to those in mammals , following exposure to toxic gases and airborne particulates . 
 we suggest that these differences can be productively exploited to further our understanding of the basic mechanisms of inhalant toxicology ( gases and particulates ) . the large mass - specific gas uptake by the avian respiratory system , at rest and especially during exercise , 
 could be exploited as a sensitive monitor of air quality . 
 birds have much to offer in our understanding of respiratory toxicology , but that expectation can only be realized by investigating , in a wide variety of avian taxa , the pathophysiologic interactions of a broad range of inhaled toxicants on the bird 's unique respiratory system.imagesp188-afigure 1.figure 2.figure 3.figure 4.figure 5 . 
 afigure 5 . 
 bfigure 5 . 
 cfigure 6.figure 7.figure 8 . 
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