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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. I am now 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. 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. As part of my fascination with our Gondwanan origins I've been running tours to South America for the past few years.

Wednesday, 9 January 2013

Sometimes Nature Really IS Black and White! #1

Maybe it doesn't happen to you, but I often find I'm not really in control of what I write. OK, you may well agree that you've noticed that, but what I actually mean is that I sit down with a topic in mind, and it takes over and turns into something else. You may recall that two days ago I set out to do a simple posting on black organisms; in the process I found myself foreshadowing an additional posting on 'black-and-a-colour' organisms. When I started that, an annoying little voice said "actually, there's a whole posting to be written on black and white creatures alone". And then, for goodness sake, it started to suggest that that posting could, and should be sub-divided...

OK, who am I to argue? The first point to remember is that much of the world doesn't actually see colours as we understand them. I don't want to go too far into this here, but where we humans have three pigments in the colour-viewing cone cells of our retina, birds have four or even five, and they are different from ours, so they see 'different colours' from us - effectively they have four or five primary colours, and we wouldn't call them red, blue or yellow! That's getting close to philosophy rather than biology, but it's certainly relevant. At least some reptiles and fish also have four cone pigments (many haven't been examined). On the other hand, among mammals only primates and hoofed mammals appear to see colour. In an animal which doesn't see a range of colours, black and white is certainly a striking contrast; the same is true of animals like us which do see other colours however. The prevalence of black and white patterns among birds, which probably have the most sophisticated colour vision of any animals - certainly of any vertebrates - is testament to its effectiveness.
Pied Butcherbird Cracticus nigrogularis, Bourke, New South Wales.
Butcherbirds are never shy and retiring!
So, being pied (ie black and white, the word coming for an old English word for the European Magpie) is a good way to stand out; it's a warning, eg "I'm tough and stroppy and staying clear is the best way to deal with me." The Pied Butcherbird is a member of an Australian family of mostly large, self-confident species, mostly black, white and grey, which don't at all mind being visible - they can definitely look after themselves.

A very well-known member of the family is the Australian Magpie Cracticus tibicen, famed for its fearless defence of territory during breeding season. Its personality makes it a very successful urban bird; a few males, which apparently had bad youthful experiences, every year terrorise their neighbourhood.
Black-backed Magpie, Canberra. No bluffing involved!
Australian Magpies belong to the family Cracticidae; other large in-your-face black and white members include the currawongs, that were the subject of one of the first postings of this blog. Our Magpies were named of course from a superficial similarity (which doesn't really go much past being black and white!) to the Eurasian Magpie Pica pica.
Magpie, Barcelona (it was very early in the morning!).
These are a true crow, family Corvidae.
Almost inevitably, black and white birds, of any size, are bold and even pugnacious in defence of their nest. Indeed sometimes they almost appear to have an excess of testosterone at any time...
Common Fiscal Lanius collaris, Cameroon.
This is a large conspicuous shrike, found throughout most of sub-Saharan Africa.
Magpie-lark Grallina cyanoleuca, Longreach Queensland.
This is a large aberrant monarch flycatcher, whose pugnacity often extends to its own reflection.
Willie Wagtail Rhipidura leucophrys.This fantail (family Rhipiduridae) is small but entirely fearless, including taking on any of the
Australian Big Black-and-White Boys featured above!
African Pied Wagtail Motacilla aguimp, Murchison Falls Uganda,
another conspicuous bold small bird.
African Paradise-Flycatcher Terpsiphone viridis, Benoue National Park, Cameroon.
This is yet another stand-up-and-be-seen flycatcher, but I'm partly cheating in that this is
a colour variant (but a regular morph rather than a 'freak') of the more usual chestnut plumage.
It's a great bird though!

American Oystercatcher Haematopus palliatus, Isla de ChiloƩ, Chile.
Oystercatchers are either black or pied, and make no attempt at hiding, except when breeding.
White-cheeked Honeyeater Phylidonyris niger, Lesueur National Park, Western Australia.
Members of this genus are especially aggressive and direct in defence of 'their' flowering bush.
Chequered Swallowtail Papilio demoleus, Muttaburra, central Queensland.
This is a widespread species known by other common names elsewhere in the world.
Interestingly it is described as 'aggressive' (to other butterflies) so I've included it here.
But there may be other reasons to avoid an animal than simple belligerence; it might be toxic or have other chemical defences. The most famous of these are doubtless the American skunks, which spray mercaptans and other foul-smelling sulphur-based chemical from anal glands. They don't want to waste their investment however, so the colour is a warning to back off.
Patagonian Hog-nosed Skunk Conepatus humboldtii, Strait of Magellan, Chile.
Other, smaller animals, contain toxins - some of the species must die in the predator's learning process, but then others will be left alone. In not all small black and white animals is the toxicity proven, but it usually turns out to be the case.
Black and White Tiger Moths Spilosoma glatignyi, Big Badja Mountain, southern New South Wales.
Pierid butterfly, Bwindi Impenetrable National Park.
I bet it's toxic too, but I haven't tried it...
And on that dodgy note, I'll leave it for now. But as I flagged above, I'm coming back to this one very soon, because black and white can also be a way of avoiding attention, or of attracting it for reasons other than threats. Hope to see you then...

Back Friday.

5 comments:

Susan said...

Why are so many creatures black and white? Once again you've answered a question I've asked myself in the past and been too lazy to find out the answer to. Fantastic post.

I'm dubious about that African Pierid being poisonous though. Other Pierids are not (that I know of) and they are pretty well all black and white. Some may accumulate some toxic substances as caterpillars (eg if their host plants are in the mustard family) but these toxins have to be taken in large quantity to kill. Pierid caterpillars and butterflies are fairly popular with predators such as nesting birds in my experience.

Not sure that I would describe Checkered Swallowtails as agressive either. They probably engage in hilltopping though (their European counterpart does), which might be interpreted by some observers as agressive behaviour.

Flabmeister said...

The topic of colour perception was covered in an ABC Radio National program recently - I think http://www.abc.net.au/radionational/programs/scienceshow/radiolab-e28093-colours/4438520. It speculated amongst other things where the DNA for the extra cones etc could be inserted to the human genome. They also reported that one woman had been found who already had such a gene and could see colours the rest of us can't!

Martin

Ian Fraser said...

Susan, thanks for your kind words, and your always-valued info on insects. However the Pierid doesn't need to be poisonous - just taste bad. But, since you say that they are popular prey, that can't be it; perhaps they benefit, even only sometimes, by looking like something that might not be good to eat. Or perhaps it's something else altogether (conspicuousness for mating? likewise the Swallowtail?) and I've led everyone entirely astray!

Martin, thanks too. I hadn't heard that ABC show; good stuff. I love the idea of the woman with the extra cone cell types! I do think about that one sometimes.

Susan said...

Ian: I just don't know, but now I feel guilty about not knowing and obliged to find out :-) I'll cheat and ask the lep guys at the NMHN if they know of any literature on the subject.

Susan said...

A quick internet search has revealed at least 2 papers on the subject of Pierid pigments. Apparently the scales are white, but contain a mixture of 5 pigments related to uric acid called pterins. These pigments produce yellows in visible light and yellowy greens, bright blue and reddish blue under UV light. They fluoress in varying degrees depending on what the mix of pterins is. It appears to be for ornament ie I assume for attracting a mate. The pigments are created by the butterfly as a by-product of dietary waste material. The black markings are melanin, as you would expect. Pierids may all look extremely similar to us, but to creatures with the ability to see a wider spectrum, they are very different.