Acknowledgements
I thank the following people for providing comments and information related to the subject of bioluminescence: B. Bartlett, Dr P. J. Herring, Prof. J. Lee, Dr M. McDonald, Dr T. May, Dr O. Parkinson, and W Stanhope.
Thanks to Leslie Attard, Kate Hill, and Jeff & Debbie Keniry for their invaluable help in seeking out important literature.
Thanks to Tom Garnett whose advice helped greatly in setting the research upon its present course. Thanks also to Ron Fink who assisted so much in getting the ball rolling, and Nick Mooney who opened a door. Michael Walters and Dr Robert Prys-Jones (Natural History Museum, Tring) kindly elucidated the Barn Owl's early nomenclature and otherwise assisted with information.
My very special thanks to Stephen Debus for his encouragement, advice, editorial assistance and reading of the paper to the Conference. Mrs Susie Debus expertly re-typed the manuscript onto computer disk. Not least, thanks to Albert Golden. Mark Holdsworth and two anonymous referees commented helpfully on a draft.
Postscript
In question time, following presentation of the paper, a comment from the floor cautioned against being too dismissive of other explanations for luminescing Barn Owls. It was suggested that intrinsic bioluminescence might be the least likely explanation for the phenomenon, and that perhaps other factors should be considered, such as greater moisture levels in the environment during autumn and winter in which fungi could flourish, e.g. in tree hollows; or perhaps a seasonal emergence of fireflies that Barn Owls consume and so acquire secondary luminescence. Therefore, before time and resources are expended on the suggested laboratory tests for photophores and luciferin in Barn Owl bodies, which may prove negative, better documentation of the phenomenon in the field, by ornithologists, is required. There is scope for use of modern technology, such as video cameras, to be employed.
Another comment raised the possibility of luminescence in other Tyto species.
Author's responses
Fungus: the possibility of fungus as a cause of avian luminosity, regardless of prevailing seasonal or weather conditions, has been addressed in this paper, and for the reasons given seems to offer the least promise as an explanation or fruitful avenue of research.
Fireflies: secondary luminescence as a result of Barn Owls eating fireflies seems, for anatomical reasons, an unlikely possibility. Also, the distribution of the Min Min Light, so often a phenomenon of open, arid country, does not coincide with the limited distribution of Lampyridae. Fireflies are found usually in damp shaded places such as forests and caves, habitats unlikely to used for hunting by Barn Owls. The Sturt's Stony and Strzelecki Deserts, and the fringes of the Simpson Desert, for example, are not likely to be inhabited by fireflies.
Priorities: documentation by ornithologists, in the field and using all available technology, would be a worthwhile exercise and should complement laboratory research. Wild Barn Owls may luminesce rarely. As Barn Owls and Min Mins are not accommodating to observers, expenditure of time and resources in the field may also be unrewarding. At the time of going to press, laboratory research on Barn Owl bodies is proceeding in a voluntary capacity.
Other Tyto: the phenomenon would seem unlikely in dark-plumaged, forest-dwelling species. Perhaps it might also occur in the Grass Owl Tyto capensis, but so far all the indications point to the Barn Owl.
Appendix 1
Recent Min Min Sighting
Wheat farmer Dennis Stasinowsky of Mantung, South Australia, rang to say that on the evening of 25 th May, 2006, while repairing the breakdown of a machine with which he was planting a crop he heard Barn Owls vocalizing nearby. He believed there were at least two birds involved and that they were in close proximity to each other. Darkness by this time had overtaken him and as he was making his way to his truck to fetch a particular tool he saw a Min Min about 150 metres ahead and moving away. He said the light was not as bright as some Min Mins he had seen. Because of the darkness he could not with any accuracy judge the light's height above ground level but estimated the distance to be no more than a few metres. Within the minute the light rose suddenly to what seemed like another three or four metres, rapidly became smaller and took on a more reddish hue than previously. Soon after that it disappeared completely. While returning to the broken-down machine a Barn Owl flew by within about five metres of him.
This information does not prove a connection between the Min Min and Barn Owls, but it is interesting that both entities were in the area at the same time. At least it supported my old maxim that wherever you find a Min Min you find Barn Owls. Mantung is mallee country south of Loxton on the Murray River and in a region where both Min Mins and Barn Owls are well known. My first contact with Mr. Stasinowsky was several years ago when he reported seeing a Min Min fly into a low tree and come to rest on a branch. Shortly afterwards the light cut out and sitting in its place was a Barn Owl. Eventually the bird dropped to the ground and was joined by another Barn Owl and the two flew away together. Farmer Bill Curtin at nearby Caliph in December of 2004 reported seeing a Min Min on his property several months previous to our conversation. David Chiltern of Magee near Mantung had seen a number of Min Mins over the years and spoke of one he observed occupying itself within the walls of an old, roofless, local community hall. Away from the Mantung region and much farther south, in Tasmania, Mike Ellson of Howden told of a Min Min he had encountered near Campbell Town in 2004. He was so convinced (by the light's behaviour) that he was watching a bird that next day he sought information on luminescing birds on the Internet. It is interesting that timber worker Alex Oakley gave detailed accounts of Min Mins he and colleagues had seen over about twenty years close to Campbell Town. Reports of Barn Owl sightings in Tasmania are few; however, one noted Tasmanian ornithologist remarked that if he were looking for the species in Tasmania, around Campbell Town is where he would expect to find them. The local industries are mixed farming and timber production.
Anecdotal evidence is one thing. The primary need of the research remains a program aimed at inducing luminescence in the Barn Own under controlled conditions.
Fred Silcock
This paper was published in "Australian Raptor Studies II - Birds Australia Monograph 3", 1997. Reproduced with Author's permission.
The author has written a details book about this subject called "The Min Min Light: The Visitor Who Never Arrives".
