By the modern-pterosaur expert and author Jonathan David Whitcomb (USA):
I was a forensic videographer in 2003, when I learned about brief expeditions in Papua New Guinea: a few Americans searching for what natives of Umboi Island call "ropen." After a phone conversation with one of the explorers, Paul Nation of Granbury, Texas, I examined video footage of native eyewitnesses.
Recognizing the high credibility of the natives who were interviewed while being videotaped, I became captivated by the testimonies. In 2004 I led my own brief expedition on Umboi Island, interviewing a number of key eyewitnesses of the large featherless flying creauture. Within a few weeks, two more Americans explored that island, interviewing other eyewitnesses of the strange nocturnal ropen.
Since 2004, I have interviewed many more eyewitnesses of non-bat featherless flying creatures, many of the sightings being in other areas of the world. These include North America, Africa, Australia, and Europe. I have written a scientific paper in a peer-reviewed journal of science and have also written three nonfiction books on these astonishing flying creatures: three books in eight total editions.