Dr. McKitrick at the University of Michigan will study evolutionary relationships within a large group of birds that includes the sandpipers, stilts, plovers, gulls, terns and auks (Order Charadriiformes). This group is of great interest from an evolutionary perspective because its members, while presumably closely related, show a wide variety of adaptations for life in and around water and are consequently a very diverse assemblage. Many of these adaptations have involved internal as well as external anatomical changes. This has led to spirited debate among biologists about the significance of certain anatomical similarities and differences among these birds: do the similarities reflect close genealogical relationship or are they merely independent occurrences that have evolved in response to similar environmental conditions? This proposal will address such questions using data from the hindlimb musculature and from the anatomy of the vocal apparatus. The study will yield hypotheses about genealogical relationships within the group, as well as about how the internal anatomy has evolved. The study will also result in a large body of descriptive data that will be of great use in other comparative studies about evolutionary trends in vertebrate anatomy.