COMPARATIVE MORPHOLOGY OF THE ALIMENTARY-TRACT AND ITS GLANDULAR DERIVATIVES OF CAPTIVE BUSTARDS

This study describes the gross anatomy of the alimentary tract of Houb ara Bustards (Chlamydotis undulata macqueenii), Kori Bustards (Ardeoti s kori), Rufous-crested Bustards (Eupodotis ruficrista) and White-bell ied Bustards (Eupodotis senegalensis) maintained in captivity by the N ational Avian Research Center in the United Arab Emirates. The morphol ogy of the alimentary tract and the proportions of each region were si milar in all 4 species. The length of the oesophagus, combined provent riculus and ventriculus, small intestine, and large intestine formed 2 4.2-28.4%, 7.3-9.7%, 40.5-55.1% and 9.1-14.7% of the total alimentary tract length respectively. Neither crop nor oesophageal enlargement wa s observed in the birds examined in this study, although male Kori Bus tards possessed a saccus oralis in the oropharyngeal cavity. Oesophagi , proventriculi, ventriculi, caeca and large intestine were well devel oped in all species. The small intestine was shorter than that of othe r avian herbivores and granivores when compared on a bodyweight basis. The well differentiated stomachs and well developed caeca of the bust ards examined in this study are characteristic of omnivores. Analysis of the mean lengths of the alimentary tract components and weight of t he liver and pancreas showed sexual dimorphism in cases where male and female data were available for direct comparison.