Intestinal Morphology of Gallinaceous Birds in Relation to Food Habits

It is well known that various species of grouse can thrive on a winter diet of buds, catkins, and conifer needles that would not support a quail for a week. Why this should be so has not been determined, to my knowledge. In pursuit of a possible explanation of differential digestive abilities I started some years ago casually inspecting the alimentary tracts of various gallinaceous birds. Gross differences in the relative dimensions of intestines and caeca were noted, the browsing grouse having appreciably longer digestive tracts, especially caeca, than the quails, partridges, pheasants and turkeys which generally depend on somewhat higher quality food in the winter diet. A cursory survey of the ornithological literature yielded some data on galliform intestinal morphology (Bump, et al, 1947, for ruffed grouse; Gross, 1928, for heath hen) but apparently no comparative survey of galliforms had been made. Accordingly, over a period of time, samples of most North American galliforms were collected and intestinal tracts measured; the results are here summarized. It is not claimed that these observations completely answer the question posed above, but they undoubtedly have some bearing on the matter. At least they suggest a likely avenue of future research. I am indebted to a number of colleagues for assistance in assembling materials, particularly Frank A. Pitelka of the Museum of Vertebrate Zoology, Fr derick and Frances Hamerstrom of