Dr. Backstrom will present data from research on three avian study systems where substantial information about phenotypic traits related to fitness and reproductive isolation is available: the collared and the pied flycatcher (Ficedula hypoleuca and F. albicollis) in Europe, the house finch (Carpodacus mexican us) in North America and the emerging model, the zebra finch (Taeniopygia guttata). These species have been of great importance for research on speciation, ecology and host-parasite interactions.