Abstract

This paper presents preliminary results of comparative osteological studies of two very difficult groups of birds: smaller members of the order Passeriformes (perching birds) and the subfamily Tetraoninae (grouse and ptarmigan). Despite their small size, some passerine bones can often be distinguished on the basis of morphological characters. Using modern reference specimens, selected elements of species whose present distribution includes the Canadian prairies have been examined. The amounts of variation within and between taxa have been compared to determine the most reliable osteological characters. The most distinctive postcranial element is the humerus, with the carpometacarpus, ulna, proximal corocoid, proximal femur and quadrate also providing reliable characters for identifying passerine remains. On the other hand, the bones of most species of grouse and ptarmigan have proven virtually impossible to distinguish on the basis of morphological features. Osteometric studies conducted on modern reference specimens show a great deal of overlap in the total length of complete bones, although this measurement can in some cases reduce the number of possibilities and occasionally point to a single species. Thus in areas where more than one tetraonid species occurs, or may have occurred, identification of these bones should be made with extreme caution.