(Phys.org)—A small team of researchers from Flinders University, Centro de Investigaciones en Ciencias de la Tierra and the South Australian Museum has found evidence that suggests large flightless birds that once lived in Australia, Europe and North America were related to one another. In their paper published in Royal Society Open Science, the group describes using a variety of techniques to study the ancient birds and offers a theory on how birds that were unable to fly were related to other birds that could not fly such a great distance.