Search This Blog

Wednesday, 30 May 2012

Normal service will be resumed shortly

In 2008, and again in 2009, I indicated that I was working on some YA historical fiction, referred to as The Cornish Boy.  I then closed it down to get on with other more urgent work, but in the past couple of weeks, I have returned to it.

This (if it works—and sells) will be a sprawling work, featuring a Cornish boy who is bright, has some medical and scientific training, but has to leave Cornwall in a hurry, with killers on his trail. With the help of friends, he eludes them, gets to Australia, and as teenagers did back then, he went out with an exploring party.  There's a great deal more in book 1, but that's all you get for now (though it won't be giving too much away if I add that he makes an enemy and several good friends.

Later books see him on the Turon River gold fields; shipping as assistant naturalist on a naval expedition to map the Gulf of Carpentaria, based on the 1850s cruise of HMS Rattlesnake; helping a group of Chinese would-be gold diggers  while they are trekking from South Australia to the Victorian goldfields.  Large numbers of Chinese did this to avoid a head tax that was imposed on Chinese landing at Melbourne.

Later, he works on a paddle steamer on the Murray, marries, they make an exciting find (yes, I am being reticent there) that draws more attention from shady characters than they need, and they settle on a farm—and a few answers are at last revealed.

The four planned books run from 1851 to about 1867 and encompass a lot of Australia's key historic points.  Eureka will only be seen off-page, so to speak, but there's a lot to say about the way Australia became a nation with independence of mind. The Bulletin only emerged in the 1880s to press a fully Australian sense of nationalism, but as I will be explaining in Curious Minds, due out on October 1, the leaders in the revolution were a bunch of foreign, mostly German, naturalists.

Now watch out: here comes the pedagogue again: there is an old saying, originating with Jerome S. Bruner, that you can present any subject to a child at any developmental level. in an intellectually honest fashion.  I won't be teaching, but if I can get a few readers to "what if Jack had done this instead of that?", I have won.

You see, as I have said before, education, teaching, training, wisdom, knowledge, learning, understanding and erudition are not the same thing, even if they are cousins. That's a key consideration for me.  I have written scraps of fiction before, but this is the first serious fiction I have completed and it's big. I have finished the second draft of Book 1, and I think it works, sort of.  It's taken me ten days to knock into shape the work I did two years ago, and right now, I will be drifting off into something far fluffier.  I need a sort of writing sorbet.

There's a bit of the educator in me coming out in this series, and that's always a risk.  The main areas I will be including are all areas where I have written before, like Australian exploration, rockets and poisons, plus an area I am currently working on, which is the Australian gold rush era.  This is a major trap for old educators, who feel, a bit like Jean Auel in Clan of the Cave Bear and spin-offs, that all that hard research needs to be crammed in.  My plan is to produce a background web site, where people can test some of the assumptions.

I have made a start on that with my database of early uses of Australian language phrases and slang, where I have evidence to justify the use of terms like billy or goanna, phrases like "having a shingle loose" or "slope off", but I think I can take this further. Rather more though, I want to introduce matters like the amazing multicultural society that was Australia in the 1850s, the (to modern eyes) hidden agenda of the Chartists who, just as they were losing the struggle in Britain, were winning it in Australia.

In short, I will be trying, without preaching, without teaching, to get my readers to wonder more about what lay behind things. It's going to be a hard road to tread, a road slung on a tightrope over a minefield of mixed metaphors.

And that's why, just now, I am busy on something fluffy, involving mad sheep (they say they are mad, but can a sheep wearing a fake Viking helmet with horns be trusted?), a jewel heist, the truth about Van Gogh's ear, virtual normality and dark matter.

Among other things.  The point is, I'm otherwise engaged for a bit.

Saturday, 26 May 2012

Drawing nature

I am passably capable at drafting, but not at execution in any artistic sense, so there are no technical tips here, just some tricks and wrinkles.

In 1857, Herschel Babbage took photographic equipment out with him when he went exploring near Woomera in South Australia. Before (and even for a while after that) all explorers and biological collectors needed to be artists, or they needed to take an artist with them.

This, in fact, is part of the subject matter in my next book for the general (that's writer-code for adult or bright younger reader) market, Curious Minds. In that book, I look at the natural history collectors and the natural histoty painters who worked Australia in the 1700s and 1800s.

Painting flowers in water colour was regarded as a suitable activity for young ladies, but in time, some of the women painters did what the men did, and went out into the field, studying plants and birds and painting them. In the end, though, photography took away most of the scientific side, but people still paint plants for fun.

The job of the scientific artists was to record the colours and shapes of the flowers that would often be pressed and dried beyond recognition. Often a bird or a mammal would be skinned, with only the skin and sometimes the skull going back to people who would stuff and mount the animal, using sketches done on the spot to get the shape right. Information on the colours came from paintings and notes, because specimens often discolour.

Magpie at a picnic, Reef Beach, Sydney.
My alpha publisher these days is the National Library of Australia, in large part because that gives me access to their huge art collections,  They also like doing beautiful books, which is a boost to the ego of the writer!  Some of the artists whose work may be found at the National Library of Australia: Elizabeth Gould, John Gould, Edward Gostelow, S. T. Gill, Ferdinand Bauer, Ellis Rowan, Adam Forster and Ida McComish.

This link will take you to the place to search, but you then need to spend some time getting used to the controls.

Pelican on a street light, Broken Bay.
One good trick is to use the Limit To section and specify NLA digitised material in the drop-down menu. For example, there are 83 images of Banksias (or were when I looked just now).

If you want to try to work as those experts did, take a simple and easy subject first, a common bird like a seagull, a pigeon, a sparrow or any of the other pests that will hang around if there is a free feed.

Plants, especially fruits and seeds, are easier to paint!
Rainbow lorikeet, Cremorne, Sydney.
There is no harm or shame in taking photographs to help you with your drawing: the art comes in composing the separate scraps of image into a whole. If you are looking for a theme, why not try behavioural studies, like the aggressive postures of seagulls?

Magpies will lurk near a picnic looking for food, kookaburras will fly through and steal, pelicans will watch you if you are cleaning fish, and rainbow lorikeets love to steal the little paper packets of sugar where coffee is sold.

Hooke's view of a human louse, on
a hair. Most people had 
lice back  
then, but they could not
see the detail. 

On the other hand, there are times when drawings are best. Scattered through most books on biological matters, there will be a number of line drawings of small animals, part of a tradition that began in 1665, when Robert Hooke published a book called Micrographia.  Some might say the tradition goes back much further, but that's where I set the start.  My blog, I get to choose!

Rich Londoners could marvel at the details of a flea without having to squint through a microscope, and a number of them could look at the flea at the same time. Best of all, the drawing could show all parts of the flea in sharp focus.

Mind you, Hooke wasn't all that good an artist, and biologists believe that many of the drawings were actually the work of Sir Christopher Wren, who famously designed St Paul's Cathedral in London.

Biological illustrators use all sorts of tricks to get their pictures just right, so it is a craft and a science, as much as an art. Do a web search on <biological illustration> to discover a whole new world!

One trick that I used to good effect in the days of 35 mm slides was to have a slide projector that I pick up for $5 at a jumble sale, mounted above my desk.  Perhaps, if you have access to a "data projector", you may be able to use that to get your images onto paper.

If you have the skill and talent (and as I said, I don't!), you will never look back.  Otherwise, be like me and use the camera.

Either way, you will be collecting nature without doing any harm.

Sunday, 20 May 2012

Close-up photography

If it is possible, get a camera that can take close-up (macro) shots, and read the instructions. The technology is too variable for me to go into it here, and I also lack the expertise to give really good advice. That said, I have developed some cunning over the years, so here are some of the tricks you need to get the best possible photographs:

First and foremost, read your camera's manual.

Second, with a digital camera, there is no excuse for not taking lots of shots.  Go wild!  Experiment!

Hand-held shots are always a problem, because of camera shake. At the very least, prop your camera against a log or a rock, but if possible, use a tripod. A Joby Gorillapod is excellent (and I use one), but if money is in short supply, go to the web and search on <gorilla pod make> and follow the instructions. The bolt size you want is 1/4".

Whenever possible, I use a remote control, but my cameras (Canon Powershot G2, G11 and G12) don't do this. Luckily, most cameras also have a timer setting that allows you to press the button and let go of the camera before the shot is taken.

Insects are 'cold-blooded', which really means that their insides are at the same temperature as their surroundings. If you chill them down in a refrigerator, you can get unblurred shots more easily.

This is an Australian bull-ant, about 20 mm long, and these things have a ferocious sting in their abdomen. They grab you with the nippers, and within a second, they have doubled up and injected something nasty (formic acid??) under your skin.

If you get around in the Australian bush, shorts are best, because an ant inside jeans or trousers is hard to dislodge, but when you feel the 'nip' on bare skin, you can knock the ant off with a glancing blow.

Anyhow, even though this ant was iced, I didn't want her getting loose, I set her up on blue paper, on a plastic tray, sitting on pebbles in a dish of water.

When I am photographing wildflowers, I always carry a few pieces of wire that I can use to make hooks to attach the flower stem to a solid branch.

Even though it is "out-of-shot", the hook will slow the flower's movement in the breeze.

Of course, if the day is sunny enough, then the speed of the shutter will 'freeze' the picture in any case. I also use gaffer tape, bulldog clips and string at times.

The fourth picture shows the dandelion flower and beaker, showing the set-up that gave me the result.

Note the unusual use of a clothes peg.

You can get better shots when your subject is against a plain background. You can see an example of this is the bull ant shot above.

Carry some A4 sheets of coloured manila cardboard in a folder and hang these behind a flower (or get somebody to hold them) and you can also put them under an insect. Black and light blue are probably the best.

And here is the set-up for a shot of the angle-of-rest apparatus that I used in a blog entry on ant lions, using a cardboard background.

This way, you get a rather neater image than you would if the author's messy work bench was visible.

As I mentioned in an entry on animal tracks, you can get better shots of animal tracks by leaving a smoothed sand tray near a feeder.

Always put something down, not too far from the paw print as a scale object. Locate the object so you can crop it out if you wish.

This dingo print in dried mud was taken in the Kimberleys. The sun was high, making the shot less than ideal.

At least the 50-cent coin provides a sense of scale, but it was a bit too close, and would be hard to crop out.

This wallaby print was taken near Sydney with a more slanting light. It lacks a scale object, but note the tyre tread mark at the top.

For some wildlife photography, the best trick of all is to have a camera which is triggered by a motion sensor, but that is heavy stuff, so check the details yourself. I don't own one of those, alas!

Shadows are more of a problem when you are photographing something on a smooth surface. You can 'fill in' the shadows with a flash (a ring flash is expensive but best).

You can also use crinkled aluminium foil to reflect light from another angle. You need a helper or helpers for this, and you need to know that heat is reflected as well as light, so you may need to be quick to get a caterpillar before it takes off out of the heat.

Looking at the shadows in the first caterpillar, you can see that the sun's light on one side is filled in by a mirror, placed just out of shot on the right.

The second caterpillar was on a track beside the Swan River near North Fremantle. I squatted, used a hand-held camera and a macro setting.  I took about twenty shots to get one good one.  Remember: there is no film to waste any more!

An angled shot often leaves part of the animal out of focus, because it is too close or too far from the lens. Depending on your camera, if you can reduce the aperture, this will increase the depth of field for your shot. This helps explain why so many scientists still rely on line drawings. I will turn to that next time, but once again, I can claim no expertise.

Wednesday, 16 May 2012

The collector's art

In the middle 1800s, the homes of wealthy people were full of dead things. No home was complete without cases of pinned insects or stuffed birds, stuffed animals on stands, animal heads on the wall and animal skins on the floor as rugs. Most naturalists got their start collecting live things, killing them, identifying them and preserving them for sale to rich "collectors".

 Until binoculars were invented in 1859, the year Charles Darwin published The Origin of Species, the only way to study birds up close was to shoot them or trap them in nets.

When I was young, around 1959, most natural history guides would still have been mainly about how to collect, kill, prepare, look after and store collections of dead things. Fashions change, and we try to avoid that, these days.

There is still an occasional need to kill specimens. I know from experience that a huntsman spider will never stay still long enough to be photographed.

This shot was deliberately over-exposed. Can you see why?
In fact, if you poke around in libraries, you may find a 1986 book of mine which describes a chemical killing jar, but I no longer recommend those.

The best way to slow down an invertebrate is to put it in the refrigerator, and the best way to kill an invertebrate is to put it in the freezer. This is gentle and painless, but remember to put the spider in a jar first, or great-aunt Ermyntrude may get a nasty shock!

After an hour or so, the animal will have lost consciousness and died, but it will also be contorted and twisted out of shape.

A dead huntsman spider, pinned out to dry in a selected pose.

The same applies to most animals that you find already dead, as was the case with the spider in the shots shown here.

Another view.
In either case, this is when you need to put the animal in a high humidity relaxing jar for a few hours. This softens the animal up so you can arrange it in a more lifelike pose, using pins to hold it in place while it dries.

(The details of how to make a high himidity jar are on pages 192-193 of Australian Backyard Naturalist, and if you look at the sample pages from the book on Google Books, you can see page 193 for free.

Or just go to this link, because I later added it to this blog.

I use entomology pins because they are long and easy to use, but I don't push them through the animal. Instead, I use them to make a scaffolding that holds each part in place while it dries, pinning the spider onto a piece of foam sheeting.

After that, you are ready to take pictures like the top pair.

Monday, 14 May 2012

Rainy day spiders

Sometimes I need a post that basically says "I aitn't dead yet".  This is one of those, because I'm busy on other stuff.  There's a radio talk to clean up, there's a book to start, there are two in progress that need a shove, because they stopped progressing

There is hardly anything in Australian Backyard Naturalist about leaf-curling spiders, trapdoor spiders, spiders that live under water, net-casting spiders, spiders that use lassos or spitting spiders. The reason is simple: it wasn't a book about spiders, but the other arachnids are also fun.  Go and burrow!

A photographic challenge for you: try photographing a flower spider (also called a crab spider) in different flowers or against backgrounds of different colours and see if you can catch it changing colour. Some books say American species like Misumena vatia can change colour, but I've never seen any Diaea in Australia change colour.

The arachnids get their name from the old Greek legend of Arachne. Track this story down, and on a wet day, retell it in your own words, with a uniquely Australian flavour. We are allowed to play with science, you know!

I may come back when I am less busy, and stick a couple of spider pictures in.  Now, it's head down, back to the wall, shoulder to the wheel and nose to the grindstone!

Friday, 11 May 2012

Floating filamentous algae

One dish in two different roles, but
here comes a third way to use it:
In the last entry, I described a method for pressing specimens of land plants.

It is also possible to dry and preserve algae and seaweeds, though some of the thick plants like kelp can be a bit of a challenge. Some thick seaweeds can be pressed if they are soaked in hot water first, but you need to use hot sea water, because many of them just collapse in hot fresh water.

The one thing you must have is a shallow dish.  Mine is a bit of an antique: once it would have been used in the kitchen, but for me, it is everything from an algal culture receptacle to an ant lion home, and as I will explain, one of these days, even as a device for gauging rates of evaporation.

You can't just put the thin seaweeds in newspaper, because most of the algae will just bunch up into a dark clump. You need to 'float' them onto paper, so the parts spread out, and the second picture shows you how to do it.

Like the plant press in the last entry, it comes from my 1986 book, Exploring the Environment. I own the copyright and explicitly release this image into the public domain.

Get a fair sample of an alga into a shallow dish in water. Then slip a sheet of reasonably stiff card or heavy drawing paper underneath the plant. Once you have the alga positioned, slide the sheet out of the water, picking up the strands of the alga as you do, using a small artist's brush. Leave the sheet of paper to dry for a while on thick newspaper and then press it in the usual way.

You can improve on this method.  The one thing you can't leave out is the use of the brush to move the alga in the water. Using a backing board of some sort behind the paper may help. You may need to experiment with covering the more filamentous algae with plastic (on one side only!) when you put it into its first wrap of newspaper. With the back of the sheet uncovered, water will still escape.

The main thing is to know that seaweeds can be floated onto a flat surface.  After that, you are ready to go!

Collecting and pressing plants

If you are going to collect plants in a scientific way, you should use a proper plant press. The drawing on the right shows a good design for one of the two identical frames that you need.

(It is, by the way, scanned-in from my well and truly out of print Exploring the Environment. The copyright is mine, and I hereby place this image in the public domain.)

The best material is 19 x 6 mm softwood, held together with small nails (I called them "panel pins" in 1985 when I did this pic, but going on more recent experience, I recommend using 1" flatheads).

The nails need to be long enough to go right through both pieces, but be sure to turn the frame over and knock the points down flat (and think about where the nail points will go when you first drive them through!). The size needs to be about that of a sheet of tabloid newspaper, because you will use a lot of newspapers to dry your specimens.

You need to know something about plants before you start collecting specimens, so do some research or ask. You need to be able to guess which species might be protected, and you need to know if you are allowed to collect or not. (If you are in a botanic gardens or a national park, the answer is "no!").

Your specimen size will depend on the mounting paper the plants will go on. Use secateurs or clippers to make a neat cut. The ideal time to take a specimen is when it has both flowers and seed on it.

Some plants may be too large for the amateur to press in the usual way.  This is a cabbage tree palm.
Unless you are carrying your press with you (not a good idea because it will be large), put each specimen in a separate plastic bag with a slip of paper noting where and when you collected it, the type of plant (herb, shrub, tree, big tree, maybe some measurements), other nearby plants and whether you are in forest, scrub or something else, and if possible, the type of soil.

Noting the soil type might seem odd, but some plant species are very fussy about where they grow, and your records might reveal this. Around Sydney, geologists used to work out where shale is exposed from aerial photographs. If they can see cabbage-tree palms, there is shale rock beneath the tree canopy.

You can also use a GPS to locate the plant if you have one, and maybe take a photo of the plant with a digital camera (ah, the marvellous toys that the younger generation have today.  Sheer looxury, that's what it is!)

When you get home, put the specimen and the finder note inside two sheets of newspaper, stack the specimens on one frame, put the other frame on top and use weights, a rope or a belt to squeeze the two frames together.

You will probably have collected a number of insects and spiders with your plants, so try to store the press somewhere outside that is dry and warm.

You should change the newspaper every day, and don't forget to transfer the finder note over at the same time. The old paper can be put in the recycling, but don't use it for other plants, because it will be damp.

After about a week, once the plant specimens are really dry and flat, you can tape or glue them to sheets of white paper. Use PVA wood glue and apply light pressure for an hour. Glue the finder note to the same sheet and store your specimens in a box. In a proper herbarium, poisonous chemicals like camphor and naphthalene are often used to keep insect pests away: these are not hood around the domestic scene.

Now you need to name your plants. You have several choices to identify plants. You can ask an expert, you can look at a book with photos produced by an expert, or you can use a dichotomous key, a set of questions that you work through until you have only one species left. Using a key is hard, but if you are able to ask an expert, you are also able to ask an expert to help you by showing you how to use a key.

In October, my book Curious Minds will be released in Australia.  There you can read about some of the tribulations of early collectors in Australia: the ones who were inadvertently poisoned by Macrozamia seeds (de Vlamingh's party at the Swan River and Banks' party in Queensland among them), and where the type specimens of the early collectors ended up.  You can see two zamias here on the right.

The majority of the type specimens taken by early Europeans are still held at Kew, outside London, but the French collector La Billardière's specimens are now in Florence!

You will also read of Ellis Rowan, an exquisite water-colourist who did wildflowers so accurately that any botanist can spot their genus and species, but who was hopeless at naming plants, and often had to be corrected. She also won lots of awards, much to the annoyance of the mere males who failed to be as recognised, and who engaged in a long-running, vindictive and spiteful war against her.  The usually well-regarded Julian Ashton was one of the most vicious. His motivation seems to have been that she had the temerity to gain a higher award than Julian's brother George.

I'm glad botanists aren't like that.  Well, not often...

Tuesday, 8 May 2012

A home-made rain gauge

Once you start looking at weather, you may want a rain gauge. You can buy one, of course, but you can also make one from scrap materials.

The last thing you want with an evaporation pan (I'll come to that later) is rain water falling in it, the last thing you want in a rain gauge is evaporation, so it needs a bit of design to control for that and to stop rain splashing out.

This entry is essentially a set of partly-baked ideas, because before I got too far, I dropped this one from the book: that's why this entry is a bit deficient in photos.  Grab the idea and run with it, changing it as you go.

For my model, I decided to take a 1-litre milk bottle and lop the top off to make a funnel that would catch the rain and lead it in, and at the same time, stop too much loss by evaporation.

To make the base more stable and also to make the bottom level, I filled the bottom with water, added plaster.

Note well: you need to put down newspaper to work on before you use plaster, and you should clean up any spilled plaster with a vacuum cleaner.

If you have excess water in a container, the plaster powder settles down to a nice flat surface and it still sets, so use a spatula to add plaster powder to an excess of water.  Bounce the container up and down to flatten the plaster.

Then let the plaster set for an hour (20 minutes is enough, but it does no harm to be patient) and pour off the excess water.

On testing, I found that a bit of the water soaked into the plaster, so if I do this again, I will add water-based paint to seal the plaster. Also, if I did this again, I might use cement.

My first tests revealed that the rain gauge still blew over, so I made a stand for it from scrap timber. The second and third pictures show the basic design, near enough for you to make your own.

The wire came from a coat hanger, but note the spiral on the dowel. This is a special feature, because when you hold it, the spiral will slide up and down the dowel stick easily enough.

When you let go and it is hanging under its own weight, it clings.  You can see this in the second photograph.

I used this design feature later when I was rigging home-made stands for lights than I use for close-up and micro-photography—I'll talk about those some other time.

To finish it off, I suggest adding a scale up the side.

* * * * * * *
This blog covers quite a few different things, so I tag each post. I also blog about history, and I am currently writing a series of books called Not your usual... and the first two have been accepted by Five Mile Press, The offcuts appear here with the tag Not Your Usual... . For a taste of Australian tall tales, try the tags Speewah or Crooked Mick.   For a miscellany of oddities, try the tag temporary obsessions. And language us covered under the tags Descants and Curiosities, while stuff about small life is under Wee beasties.

Sunday, 6 May 2012

Tree rings and climate measures

This was a puzzler box that I planned to include in one of the plants chapters in Australian Backyard Explorer, before we decided to drop the whole plants side. Oh well, here it is in the blog instead.

By the way, you can now have a good look at the book for free, courtesy of Google Books.

Part of one of the earliest descriptions of tracking
old weather by looking at tree rings, from Scientific
American, 10 September, 1859, page 178. You can
click on the image to enlarge it a bit (or use the link
below to view it online).
You can measure the age of trees by looking at the growth rings laid down each year. Tree rings form because the cells of wood formed in winter are smaller, which makes the wood look darker. In a bad season, the ring will not be as wide.

Professional scientists have tools that drill into trees to take core samples, but making holes isn't good for the tree, so you need to find a tree stump or a section of a log that you can cut. You may need to sand or smooth the surface with a plane or a sander, and the rings are clearer if you varnish the wood or rub grease into it.

Count the rings carefully, from the outside in. How old is the tree, if there is one ring each year? If you can get a second log from another tree, cut a few years earlier, see if you can match up the patterns of rings between the two trees. Matching rings is the basis of a clever branch of science called dendrochronology. Look it up, one rainy day.

As you can see from the article above, the idea isn't new. Here is a link to the complete article in Scientific American. The interface isn't the easiest I have ever used, and one of my friends even calls it user-ferocious, but I recommend it as one that is well worth persevering with.
A neat use of tree rings.
When a new painting by a famous painter suddenly appears from nowhere, everybody wonders if it might be a forgery, so the tests begin. Are the clothing fashions in the painting correct for the period, do the brush strokes go the right way for that artist? If they are correct, is the paint what it should be, or are there modern pigments? Is the canvas or wood under the paint right for the date of the picture? What do X-rays show us about how the layers were put in place?
A few years ago, a major problem arose with early English and Dutch paintings on panels of oak wood. Using what we know about tree rings, the wood in many well-documented Rembrandt works did not match the standard patterns of oak trees in western Europe, but the paintings were definitely Rembrandts, known and recorded since his time.
We now know that timber merchants in the Netherlands imported oak from somewhere around Poland or Lithuania, where the annual climate patterns were different, so the tree ring patterns were different as well.
If you plan to forge Rembrandts, you have to get oak from the right place and it has to be the right age. Then you must make up the right pigments, learn how to do the brush strokes, learn how to do the base coats, know about styles of dress from those times, and quite a lot more. It might pay less, but how about digging ditches as a career? It would certainly be easier!
There is an Australian aspect to this story as well.

The Dutch ship Batavia was wrecked off the West Australian coast in 1629, and some of the oak planks from the wreck have been tested by scientists from the Netherlands. The patterns show that these planks also came from Poland from oak trees that were acorns in about 1325!

But can you do some detective work like that in your garden?

A footnote added  May 17: I came across a mention today of alleged Stradivarius violins being declared a fake, based on tree-ring analysis, somewhere in Germany.  I couldn't find a link to that, but I did find this story from the University of Arkansas: Summary: "We can’t confirm that this is a Stradivarius, but we can say that it’s in the right time frame."

Thursday, 3 May 2012

More about animal tracks

This follows on from The mysterious cloven-hoofed animals of Australia.

These two photos are old slides (notice the lens cap, used as a scale!).

The shots show late afternoon tracks on a beach.

No matter what sort of animal you are after, tracks in sand are seen best when the sun is low in the sky. That means winter is better than summer, but early morning and late afternoon are much better, because the high and low parts are contrasted better. (This also applies if you are looking for Aboriginal rock engravings, or when you are looking at the impressions on a sheet of paper, left by somebody writing on the sheet above.)

If you live near sand dunes (or can get to some), you will have no shortage of animal tracks to study, but the problem is that most of the time, you won't know what made the tracks.

The best way to collect tracks in your backyard is to leave out either food or water in the middle of a patch of smooth, dry sand. To keep it dry, you may like to rig a temporary awning of "poly tarp" or something similar, or use a tray that you can take inside when it rains. Then you just need to observe carefully. Once again, you won't know what made the tracks, though I will come back to that later.

An easy way to get tracks that you can identify is to use captured animals—you can always let them go later.  You will need either some flat, dry, clean sand, or a large tin lid, candle, pliers, large spider (orb-weaver or a huntsman) or a lizard of reasonable length (say >10 cm long) or a large beetle.  In what follows, I will just say "spider", but feel free to improvise or change the animal.  Basically, I am suggesting that you try this old method as a starting-point, and see if you can adapt it.

In either case, you will need two pieces of wood about 30 cm long.  You will probably need a jar with a lid and some cardboard or a brush to catch your test animal. You will definitely need a large water container like a baby bath and some bricks or wood blocks. Most experiments like this work best when the apparatus is set up in a large dish like a baby's plastic bath with some water in the bottom. Set everything up on wood blocks or bricks, and use the water as a sort of moat to keep the spider from escaping.

Spiders are most easily caught in the evening, after they have made their webs. Take the jar and use a camel hair brush to urge the spider to move in the right direction then catch it as it drops off the web.

I don't recommend getting snake tracks using any
other method than the one I used here, where I
took my shot after the snake was well and truly
Light a candle and use the pliers to hold the tin lid over the flame, moving it around until the whole of the surface of the lid is black. Watch out that you don't get burned!

Once the lid has cooled, you can let your spider walk across it between the two pieces of wood, to collect spider tracks. You will get a neater result if the wood pieces rest on something else, like two matches, and don't touch the tin lid. You could also use an old light-coloured dinner plate instead of a tin lid.

For comparison, try the same large spider on smooth dry sand. Does it leave a track?

Note: the lid/plate method works well with beetles, centipedes and lizards. Catch a flat spider, the sort which lives under the bark of gum trees, and compare its tracks with those of an orb weaver. After you have collected a variety of spider tracks, see whether you can learn to identify a species by the track it makes. (I tried this and I couldn't!)

Next time, I'll say a bit about tracks in mud.