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I've been a Canberran since moving here from Adelaide on the first day of 1980. I now live in suburban Duffy with my partner Louise Maher, ABC 666 radio and on-line journalist. Among my early memories is following Sleepy Lizards (Shinglebacks) around the paddocks north of Adelaide, guarded by the faithful bull terrier. I have always been passionate about the natural world, trying to understand how it works, how the nature of Australia came to be, and sharing those understandings. My especial passions are birds, orchids and mammals. For much of my life I have been a full-time naturalist, running bush tours, writing books etc, doing consultancies, presenting a regular radio slot on local ABC, chairing a government environment advisory committee and running adult education classes. Recently I have eased back somewhat, but am still writing, teaching, doing some radio work and running overseas tours - as part of my fascination with our Gondwanan origins I've been running tours to South America for the past decade. I was awarded the Australian Plants Society Award in 2001 and the Australian Natural History Medallion in 2006, both for services to education and conservation.

Thursday, 20 December 2012

All White Again

I might as well finish off yesterday's foray into white organisms, given that I have a list other potential pictures cluttering up my desk, and I didn't say anything about how or why animals or fungi or plants - or rather flowers - are white. When a surface (living or otherwise) absorbs some light wavelengths and reflects others, it is the reflected light we see and the wavelength of that light determines what colour we interpret the object as being. White is not a wavelength or colour, but the combination of all visible wavelengths; clouds or snow look white because they reflect virtually all light. (I hasten to say that I'm no physicist, and this is the simplified version!)

A white flower is very visible to pollinators, especially in dim light - many flowers which are pollinated by night flying moths or bats are white, though many other flowers use white to be conspicuous to daytime visitors. On the other hand animals don't necessarily want to be very visible. It is relevant that very few small animals are white; for instance quite a few larger non-passerine birds are, but almost no small passerines. One situation in which white is advantageous is against a white background, and we can easily think of white Arctic animals in particular, but I've spent little time in snowy places and can't offer pictures of these beautiful beasts. 

Quite a few waterbirds are white underneath; these tend to be hunters, which don't want to be too obvious to small animals below them in water. Presumably they are harder to see from underneath against a glarey background than a dark object would be. 
Large fungi, Korup National Park, western Cameroon.
orchid Sobralia virginalis, Peruvian Amazonia.
Royal Spoonbill Platalea regia, Canberra.
Splendid Everlasting Daisies Rhodanthe chlorocephala splendida, Nallan Station, Western Australia.
Rough-barked Angophora Angophora floribunda, Araluen Valley, New South Wales.
Butterfly, Bwindi Impenetrable National Park, Uganda.
Quilineja Luzuriaga polyphylla, Family Philesiaceae,
a beautiful wet forest climber, Alerce Andino National Park, Chile.
Red-tailed Tropicbird Phaethon rubricauda, Lord Howe Island.
Watching these seemingly impossibly white birds flying off the Malabar Cliffs on the north coast
of Lord Howe is reason enough to go there!
Lambswool Lachnostachys eriobotrya, Family Chloanthaceae, Kalarri National Park, Western Australia.
Carissa sp., Family Rubiaceae, central Cameroon.

Little Corellas Cacatua sanguinea, Bourke, New South Wales.
And on that romantic note I'll leave you to wander off, wondering whitely...

5 comments:

Susan said...

The butterfly is Pieridae.

Bush and Beach (Australia) said...

That Royal Spoonbill is impressive. Great photos!!

Ian Fraser said...

Thanks again Susan. I wasn't game to venture even a guess for that part of the world, but it certainly looks like our familiar Cabbage White (plus some dinky di Australian members!).

And thanks Leanne - Royal Spoonbills in their courtship attire really are magnificent. Not sure how they got to be lumbered with 'royal' though...

Susan said...

Ian: I know what you mean -- it's always dodgy to ID stuff outside your home territory, but I'd be willing to put money on this being a Pierid. I'd go further and say it is within Pierinae. It would be interesting to see what the underside looks like -- many of the Pierinae have beautiful mottled undersides.

Ian Fraser said...

Your knowledge of entomology (and fungi!) is clearly better than mine, so I won't be risking my money against yours. As for the undersides, I may just have to go back (or you will...).