This work sets out to examine four taxa of birds from the Quaternary of Europe that exhibit interesting morphological anomalies - cranes (Grus), grouse/ptarmigans (Lagopus), ravens (Corvus corax) and starlings (Sturnus) - to address whether these were the result of inter- or intraspecific processes. Modern skeletal material of these taxa from a wide geographical area was examined so as to make a more realistic assessment of the fossils than had previously been achieved. Similarly, fossils were studied from a wider geographical and temporal range than before. The study of the four chosen taxa was carried out with an acknowledgement of a variety of theoretical issues in biology, which affect the interpretation of such fossils.