About Me

My photo


Monday, 31 August 2015

Colours in Nature - orange; birds

Time for another in my sporadic series of Colours in Nature; for the most recent, see here and you can work back from there. Alternatively, go to Labels to the right of this posting, and look for Colours in Nature.

A serious problem I found when putting this mini-series on orange together was to define the colour! Technically it's between yellow and red, but it turned out not to be that straightforward. We all tend to interpret colours somewhat differently - at home there is an ongoing dispute about the distinction between blue and purple - and I'm finding it very hard to draw a line between orange and chestnut/rusty. I think there's probably just a continuum, so I've tended to err on the side of caution and include here only animals (we'll get to plants later) which look to me to be obviously orange. That of course is no guarantee I'll not get into trouble anyway! Ultimately these colour postings are intended simply to be a celebration of organisms and their colours, so don't get too exasperated if a pic doesn't look orange to you - I promise that it does to me! And in time I will definitely do one on rusty-looking animals, when more mammals will get a go (though a few, interestingly primates especially, have made it into this orange series).

Things are compounded by how we've named orange-rusty-red animals too - think of the Red Fox or Red Kangaroo for instance, which some call orange, though I would probably allocate them to the rusty/chestnut department, but few of us would normally call that colour 'red'. 

With those provisos, let's start. Orange, like red and yellow as we might imagine, is mostly formed in animals from carotenoids obtained from plants. See here for more on this, but it can be an energetically expensive process, though presumably worth it in order to stand out from the crowd.

Some birds carry 'orange' in their name, making it easy to home in on them.
Pair of Orange Chats Epthianura aurifrons on the bitumen north of Bourke, New South Wales.
Only the male has to go to the expense of colouring-up.
The Australian chats are now known to primarily insectivorous honeyeaters.
Orange-breasted Fruiteater Pipreola jucunda, Mindo Valley, Ecuador.
Not a great photo, but a great bird; fruiteaters are cotingas.
South Africa's Orange-bellied Sunbird is another badge-wearing Orange bird, but my photo of it really is too terrible to publish here or anywhere else!
Red-collared Lorikeet Trichoglossus rubritorquis, Darwin.
'Red-collared'? Seriously?! After decades of dithering this tropical species is now generally accepted
as a separate species from the widespread Rainbow Lorikeet. T. moluccanus.
Other birds which I see pretty unambiguously as orange are labelled rufous too, to further underscore my point.
Rufous-bellied Euphonia Euphonia rufiventris, canopy tower, Sacha Lodge, Ecuadorian Amazonia.
Probably a tanager, but tanager taxonomy's an even more hazardous field than defining orange!
Rufous-backed (Oriental Dwarf) Kingfisher Ceyx erithaca, Gomantong Caves, Sabah.
White-browed Robin-chat Cossypha hueglini, Entebbe, Uganda, one of the Old World Flycatchers, Muscicapidae.
And I will readily acknowledge that this is getting to the yellow-fawn edge of orange.
Some birds feature a nice orange highlight, often on a yellow background.
Gilded Barbets Capito auratus, canopy tower, Sacha Lodge, Ecuadorian Amazonia.
The New World barbets are separated out now at family level from the Old World ones.
Yellow Warbler Dendroica aestiva, Santa Cruz, Galápagos.
This lovely little bird is everywhere in the Galápagos, and utterly unconcerned about humans
(or about the confusion they're in over its taxonomy).
Other bird body parts than feathers can be orange of course, notably bills and legs.
Zebra Finches Taeniopygia guttata, central Australia.
I never need an excuse to feature Zebbies, an amazing dryland bird which will surely star in its own posting one day.
Ashy-headed Geese Chloephaga poliocephala, Torres del Paine NP, southern Chile.
Actually I reckon they score twice, but even if you reckon the breast is more chestnut than red,
you can't argue about the legs.
The South American 'geese' are actually much more closely related to shelducks.
Orange-footed Scrubfowl Megapodius reinwardt, Darwin; a megapode (mound-builder),
incubating its eggs by the heat of decomposing vegetation in a huge mound of litter which it builds and maintains.
The mystery here is why 'orange-footed', when the entire leg is self-evidently orange?
Ah well, mysteries are good for us. 

I'll continue this next time, by the magic of Blogger, while I'm still in South America; we'll look then at other orange vertebrates.


Wednesday, 19 August 2015

Spotlight on Small Game in Borneo

The Nanga Sumpa Lodge is a highlight of a visit to Sarawak in northern Borneo. Run by the local Iban community it is relatively basic, but clean and comfortable - I've seen much worse elsewhere - in a remote area accessible only by boat on the edge of the Batang Ai National Park.
Approximate location of Nanga Sumpa in southern Sarawak.
In a future posting I'll talk more about the lodge itself, on the banks of the Delok River, and the forest, but for now I'm going to revisit a delightful night walk we did from the lodge, in the grounds and along the adjacent creek which flows into the Delok, and back through the edge of the nearby village. We had no especial expectations, but despite seeing no large animals at all, enjoyed a very rich nature walk. Sadly I cannot identify most of the animals we saw with any precision, though as ever I'd be grateful for any suggestions you can offer.

The wildlife experiences started before we even left the lovely open-sided dining area, with exquisite little Short-nosed Fruit Bats Cynopterus brachyotis roosting on the ceiling; why they were roosting at night instead of being out earning an honest nocturnal living I couldn't say.
Short-nosed Fruit Bat taking a break from its night-job, which involves eating fruit pulp and nectar,
in the process pollinating and dispersing the seeds of many rainforest trees. It is found throughout southern Asia.
To someone like me used to seeing big fruit bats, this one is tiny -
less than 10cm long and weighing only 30 grams or so.
A couple of their neighbours in the dining room were, by contrast, hard at work hunting insects across the walls and ceiling.
House Gecko Hemidactylus sp.; in case you were wondering, it's on a whiteboard!
Another gecko, which I can't offer a name for, making the most of technology by lurking
inside the open light fitting. Good for it, but a bit tricky for getting the photo.
Outside in the lodge grounds, other hunters were afoot.
This was a very impressive big Wolf Spider Family Lycosidae; if I were smaller, I'd have been very nervous indeed.
Though more spiders awaited us when we took to the creek, not all the lodge inhabitants were carnivores.
This is a big Tractor Millipede, like all of its kind a complete vegetarian, recycling the forest floor litter.
I think the genus is Barydesmus; like every member of its entire Order, Polydesmida, it has entirely dispensed with eyes.
The suggestion that we take to the creek to continue our walk met with some apprehension, but was inspired, with many more animals seen on the banks and in the water itself, including a couple of impressive spiders.
A water spider, spreading its legs so that at least part of the spider's weight is borne by the water surface.
I would surmise that it was hunting tiny fish.
On the bank another impressive hunter, with a reputation.
Tarantula at the mouth of its burrow, awaiting a passing dinner.
I think this is one of the 'earth tigers' of sub-family Ornithoctoninae.
Frogs, perhaps unsurprisingly, featured strongly along the banks, the most dramatic being a huge Giant River Toad Bufo (or Phrynoidis) juxtasper.
The Giant River Toad is found only in Borneo and Sumatra.
This one clearly forgot the mosquito repellant!
White-lipped (or Copper-cheeked) Frog Hylarana raniceps.Two of these inhabited a retired canoe at the water's edge.
Cinnamon Frog Nyctixalus pictus, a climbing shrub frog of the family Rhacophoridae.
Striped (or Spotted) Stream Frog Hylarana signata, another beautiful frog in the same genus
as the White-lipped Frog we saw earlier.
Then we entered the forest at the edge of the village across the stream, where several more tiny delights awaited us on the foliage.
A minute snail with a very strange shell arrangement that I couldn't - and still can't - quite make out.
A very bright green little katydid.
An extremely hairy little caterpillar, which would doubtless be very uncomfortable indeed to encounter.
A nest of tiny ants in a rolled leaf; probably also worth admiring from a respectful distance.
And finally, on our return to the lodge, this very lovely yellow moth awaited us.
Of course I'd have liked to see a mammal or an owl as well, but it was still a night to remember; we must all learn to appreciate the little things.


Wednesday, 12 August 2015

Across the Barkly Tableland: a great drive

One of the great drives in Australia, in my opinion only of course, is across the great wild extent of the Barkly Tableland in the north-east of the Northern Territory. It's sealed all the way, so a bit disappointing if you're looking for four-wheel drive adventure, but in the 460 kilometres from Tennant Creek on the Stuart Highway to Camooweal just inside Queensland there is only one 'settlement', the Barkly Homestead Roadhouse which also incorporates a nice camping area and rooms.

Approximate position of the Barkly Tableland - its boundaries are not precisely defined, and some
would have it stretching further east into Queensland or south in the Northern Territory.
Sealed roads notwithstanding, this is not country to take lightly; this is the start of the Tablelands Highway
which runs north from Barkly Homestead to the Carpentaria Highway near Borroloola.
And it's single lane all the way, which means pulling partly off the bitumen when someone's coming towards you.
If that someone is a huge roadtrain, then my strong advice is to get completely off and let them have the tar!
A rock thrown up by one of those could end your trip.
The Barkly is essentially a vast grassland on the cracking black soil plains which don't support tree growth; the heavy clays swell when wet and break up with deep wide cracks when dry, which pulls tree seedling roots apart. The east-west Barkly Highway however skirts the major Mitchell Grass grasslands to the north. The Tablelands Highway, running north from the Barkly Homestead (about halfway across the Barkly Highway) is a better option for viewing the pure treeless grasslands, but the eastern end of the Barkly Highway gives access to them.

Starting from the west the highway runs through lovely low shrubland with scattered eucalypts.
Acacia hilliana and Grevillea wickhamii east of Tennant Creek.
Acacia hilliana is a lovely flat-topped wattle which grows on poor soils from the Western Australian Pilbara to the Queensland border.We were there in late May, when it was in full bloom.
It was named for a remarkable character called Gerald Freer Hill, born 1880, who went from orchardist to
shorthand instructor to self-taught naturalist, to the first entomologist to be employed by the precursor of
Commonwealth Scientific and Industrial Research Organisation (the peak national science body, at least until
the current anti-science federal government began slashing its funding)
and eventually the country's foremost termite expert.
Hill collected the type specimen on one of his collecting trips to northern Australia.
This is not the only acacia to feature prominently. Turpentine Wattle Acacia lysiphloia also has a wide range across northern Australia.
Turpentine Wattle is notorious for burning away completely in a bushfire, leaving a sharp up-pointing
stake at ground level. The eucalypt is Silver Box E. pruinosa which is here at its southern-most limit,
but further north can dominate landscapes, and most attractively.
I hope you're now getting the sense of a rich - perhaps surprisingly rich if you've not experienced this country - and diverse landscape of flowering plants. Here on the fringes of the grassy plains there are certainly trees, perhaps most notably the beautiful but somewhat ominously titled Snappy Gum E. leucophloia.
Snappy Gum, which grows on gravelly soils across the tropics.
Other trees might be less familiar, though in some cases we know the genus well from shrubs in other places.
Beefwood Grevillea striata. This one is pretty straggly, but it can grow as a straight furrow-barked tree
to 15 metres tall. A few unrelated Australian trees were called beefwood by our carnivorously Freudian ancestors.
(I think we can assume they were referring to the timber's appearance rather than its culinary qualities!)
And in each of these photos grasses are prominent in the understorey. This predominance increases with the prevalence of the cracking clay soils.
Mitchell Grasses Astrebla spp. coming to the fore in ground coverage.
These support significant stock grazing on the tableland - along with native herbivores and numerous
seed-eaters - but the pressures seem not to have caused the catastrophic changes
suffered by grasslands elsewhere in Australia.
And where there are grasses - especially the spiky hummocks of Porcupine Grass, or Spinifex Triodia spp. - there will be termites in vast numbers.

Termite mounds in spinifex, Barkly Highway.
Termites in Australia have been likened in biomass to large grazing mammals in grasslands
elsewhere, with lizards playing the role of carnivores.
The point where the cracking clays suddenly take over is marked by a line so sudden as to be startling - nature is usually more nuanced than that.
Abruptly the trees are no more - the line can be seen continuing into the background.
After that, only a very occasional tree - usually growing in a sandy ephemeral stream bed - breaks
the vistas that stretch to the horizons.
Eventually, as we approach the Queensland border, we come to another unexpected sight - a river!
The James River flows south, into the Georgina River in south-west Queensland and
ultimately, in a a rare very wet La Niña year, into Lake Eyre in the deserts of South Australia.
White-faced Heron Egretta novaehollandiae and Giant Waterlilies Nymphaea gigantea;unexpected sights after hours in semi-arid shrubland and grassland!

It was quite cool when we crossed, so no reptiles to see, though there were certainly birds around, especially where water had been provided by bores for stock or at scattered rest stops, such as Sowden Bore where the following were taken.
Zebra Finches Taeniopygia guttata (one of my favourite Australians) will always find water. Their dry seed
diet compels them to drink daily, though they live in the driest parts of the continent.
These seemed entirely blasé about the warning sign!

Deep pits - I suspect from road fill quarries - provide sporadic dams (when the summer monsoons drift south) which support stands of the Broadleaf Paperbark Melaleuca viridiflora whose flowers are nearly as attractive to us as they are to visiting honeyeaters.
Brown Honeyeater Lichmera indistincta, found across most of the country except for the south-east.
Nor was its interest in the paperbark flowers purely aesthetic!

As for the grasslands, one of the birds I always look forward to on the Barkly is the elegant Australian Pratincole Stiltia isabella; its folk-name of Swallow-plover sums up its elegance very nicely. This time we found it during a late afternoon detour up the Tablelands Highway (actually looking for Letter-winged Kites, a perennial birding bête noir of mine - ironic really, given that they're white!).
Australian Pratincole on the Tablelands Highway - literally! This beautiful bird breeds in arid inland southern Australia
and in winter migrates north; some stay in tropical Australia, others continue as far as south-east Asia.
It is the only pratincole (family Glareolidae) not a member of the genus Glareola.
There is much more to the Barkly than this sketchy introduction but I do hope this has been enough to encourage you to plan your next northern Australian trip so that you can experience it for yourself. You won't regret it, and it will be more than Victorian Governor Henry Barkly, for whom it was named, ever did.


Thursday, 6 August 2015

Xanthorrhoeas; the wonderful grass-trees

Well actually they're not grasses, and only ambiguously trees, but Xanthorrhoea is never going to catch on as a common name, and the old name of 'blackboy' (for the supposed resemblance of the silhouette to an indigenous man holding a spear) has no place in today's world. I grew up in South Australia calling them Yaccas, and Balga is often used in the south-west of the country, but these are purely regional and so we seem to be left with grass-tree for now at least. It is evocative though.
Large (and very beautiful) X. glauca along the Mount Kiangarow Track, Bunya Mountains NP, Queensland.
In general the species are not distinguished at common name level, though some are, at least locally.
So, what are these plants that must look pretty strange to eyes that didn't grow up with them? For a start they're monocots, and indeed fall within the broad 'lily' grouping. (For more on lilies, see here and work forward from there.) All 30-odd species are Australian, and all belong to the genus Xanthorrhoea. Traditionally they formed their own family (though if we go far enough back we'll find they've had a convoluted taxonomic history) but modern thinking would include the aloe family Asphodelicaceae and bigger family Hemerocallidaceae (in Australia that incorporates flax lilies, rush lilies, grass lilies etc) as sub-families within Xanthorrhoeaceae.

It is a common misconception that grass-trees are an ancient group but it seems in fact that they are a recent rapidly-evolving genus.

The apparently woody stems possessed by most species are in fact hollow, though contain a fibrous matrix; the meristem, which grows outwards as well as upwards, is surrounded by the woody bases of old leaves which have dropped off as they become shaded out by newer ones above - the characteristic hanging 'skirt' of dead leaves can be seen in the photo above.
These Desert Grass-trees X. thorntonii on the Mereeni Loop Road in central Australia
exhibit the typical rough grass-tree stem, formed by the ends of the leaf bases.
This is the only grass-tree that grows in the central deserts.

Cross-section of grass-tree stem.
Note that in this old stem the inner fibrous material has rotted away - the trunk isn't truly hollow.
See Gregg Muller's helpful comment below on this aspect.
The flower spike, comprising thousands of tiny lily-like flowers, may be several metres high. Flowering does not rely on fire, but is stimulated by it. However it doesn't flower immediately, but in the winter-spring after a summer fire; if the fire comes later in the year the mass flowering may be delayed until the second winter.
X. semiplana flowers Wanilla CP, Eyre Peninsula, South Australia.
Unburnt X. glauca flower spike growing by road in Goobang NP, New South Wales.

X. platyphylla flowering in a burnt landscape, Fitzgerald River NP, Western Australia.
Each leaf base protects a growing bud, which starts growing immediately the living leaf is burnt off.

Mass post-fire flowering of X. australis, Brisbane Ranges NP, Victoria.
These flower spikes provide a huge nectar resource when flowering and an unusually wide range of pollinators visit them, from gliders, bats and other mammals at night, to insects, honeyeaters and lorikeets during the day.
Hoverfly Family Syrphidae revelling in the abundant nectar of X. glauca, Goobang NP.

Only a few of the numerous flowers will be successfully pollinated, but this still produces a large crop of hard seeds when the flower spike dries out. 
Seed cases - many of them opened - on  X. semiplana, Wanilla CP, South Australia.
To Aboriginal people, grass-trees were of immense significance. The powdery resin was used for gluing tool heads to handles and as such was an important trade item. The same resin was regarded as an important medicine, and as a lacquer for smoothing and sealing surfaces. Pieces of the flower stalk were rubbed to make fire, and the resin was very flammable, so dried leaves made excellent kindling. The stalks were used as light spear shafts. Grass-trees were also a very diverse food source; edible grubs were found at the base of the plant, the base of the young inner leaves was eaten raw or cooked, the seeds crushed to make flour, and honey was extracted from the flower spike by drawing leaves up the stem, or by soaking it in water for a sweet drink. The fibrous leaves were woven into shelters.
X. glauca overlooking the dry plains of inland south-east Queensland, Bunya Mountains NP.
Europeans processed the resin to make medicines (including, I am intrigued to read, for both diarrhoea and constipation!), perfumes, varnish and explosives; it is said that Germany imported a lot for the latter purpose (based on the picric acid it contains) prior to the first World War. The fibrous trunks were used as brake blocks for steel wagon tyres.
Ancient X. glauca, Bunya Mountains NP.
In case it wasn't clear, I just love grass-trees. They are, to me, quintessentially Australian; however I am delighted, even anxious, to share them with you wherever you're reading this. I hope you can enjoy them too, though there's no substitute for meeting them on their home ground.