The Pilliga; one of New South Wales' great forests

On the north-western slopes of NSW, some 400km inland, is a mighty forest and woodland covering some half a million hectares (5000 square kilometres) of sandstone. It is divided roughly 50:50 between reserved land and state forest (subject to logging). The reserved areas comprise Timmillallie and Pilliga National Parks, Pilliga Nature Reserve and Pilliga East and Pilliga West State Conservation Areas (see map below). The Newell Highway, one of Australia's busiest inland highways which provides the NSW section of the main route between Melbourne and Brisbane, passes through the forest for nearly 90km. This accounts for most of the distance between the towns of Coonabarabran and Narrabri, and makes for a beautiful drive, but it's better still to make time to leave the highway and drive onto the quieter forest roads. Off the highway to the west, Barradine is home to the excellent visitor information centre. The Pilliga is a favourite destination of ours, though I realise we've only camped there twice - so much else to see and do! And I really can't believe that it hasn't previously featured in one of my blog posts.

A typical roadside scene in Timmillallie NP, with Pilliga Box Eucalyptus pilligaensis
in the centre of the photo, and White Cypress Pine Callitris glaucophylla on the right.

The Pilliga is approximately at the end of the red arrow, inland
of the Great Dividing Range. See the next image for more detail.

The Pilliga forests as shown on Google Maps. You might need to click on it
to see properly, but the Newell Highway runs east of north up the centre
of the forest. For scale, the road distance from Coonabarabran in the south
to Narrabri at the very top of the map is 120km.

I'm afraid this is the best I can do to show you the reserves within the forest; click on it
to enlarge, to compare with the previous satellite image. Coonabarabran is at the lower
number 3, while Baradine is behind the left-hand number 4. Everything else that shows as
forest on the satellite photo is state forest. Courtesy NSW NPWS, where you
can also see the map much more clearly.

In the Pilliga State Conservation Area, just south-west of Narrabri, 5800ha have been protected from feral predators (ie foxes, cats and dogs) by 32km of predator-proof fencing, in a partnership project between NPWS and the Australian Wildlife Conservancy. It is planned to rerelease seven threatened mammal species which are now locally extinct, and as far as I can tell so far three (Bilbies, Bridled Nail-tail Wallabies and Brush-tailed Bettongs) are already established. To clarify, those three have definitely been released and others may have been since the undated article I've been reading. For obvious reasons the area isn't open to the public, though there are occasional guided 'open days' so it would be worth your while enquiring if you're interested.

The previous photo of the trees pretty much sums up the forest, in that it is dominated by cypress pine and box eucalypts, though of course in an area that big there is plenty of variation. Most of the photos that follow are in Timmillallie NP, west of the highway.

Again there is cypress pine here, but the ironbarks (these are probably
Red Ironbark E. sideroxylon) are also an important component.

A nice, though somewhat isolated, stand of ironbarks at Salt Cave Dam. Unfortunately
there's not much understorey here but the walk from nearby Salt Caves Picnic Area
passes through some very nice flowery heathland.

Belah Casuarina cristata, an important species in woodlands of the western slopes.

Brown Bloodwood Corymbia (or Eucalyptus) trachyphloia.

This is typically how most of us see the 'inside' of the Pilliga, on the excellent grid of
forest roads that cut through it. (The cloudy day here isn't so typical though.)
The roads themselves are generally good, built on soils eroded from
sandstone, so usually (but not always!) accessible.

The sandstone itself isn't so easy to find, but an excellent example is east of the highway at Sandstone Caves, an important cultural site and a nesting site for Peregrine Falcons. It is near the southern end of the Pilliga Nature Reserve.

Typical sandstone cliffs at the site, where a walking track circumnavigates the
impressive outcrops. Note the burnt tree trunks, which I'll get back to soon.

Windblown caves, like the ones above and below,
are fascinating (and very attractive) features of the cliffs.

Needless to say these shelters were of considerable importance to the Gamilaraay people who lived here for many thousands of years. This significance is reinforced by the presence of petroglyphs in some of the shelters, though they're not mine to interpret of course.

Petroglyphs, Sandstone Caves, above and below.

Another good encounter with sandstone can be found in Dandry Gorge, the site of a lovely walk that begins at the excellent low-key Sculptures in the Scrub picnic ground and campground, the only one in Timmallallie. The campground name refers to a series of sculptures along the top of the gorge, by and with Gamilaraay artists and advisors. I'm normally not keen on artwork in a national park/nature reserve (nature doesn't need help), but  I think the cultural significance here alters things. The 3k loop walk passes along the top of the cliff then descends into the broad gorge to return to the start.

View across Dandry gorge from the cliff top walk.

Inside Dandry Gorge.

When we did it (in August) the flowering was excellent, but I'll get to the plants soon.

A dry forest system such as dominates in the Pillliga is prone to wildfire and is adapted to a regime of it, but things are changing as we interfere with natural climatic systems. There have been two major wildfires in the Pilliga in the last six years. In January 2018 (two and a half years before we were last there) nearly 600 square kilometres (60,000ha) burnt, that is more than 10% of the entire forest, including much of Timmallallie. I pointed out burnt trees by the Sandstone Caves above, but the was stark evidence of the conflagration in most places where we were. 

View from the Sandstone Caves cliffs, August 2020

The heathland at the Salt Cave area was very intensively burnt in 2018,
but recovering as expected two and a half years later.

Callitris regrowth (with heavy early morning dew) at the Sculptures in the Scrub campground.
Callitris is mostly killed by fire and regenerates from seed.

Then in December 2023, since we were last there, a very intense fire burnt at least 120,000ha, nearly a quarter of the forest, mostly to the north of the earlier fire. I haven't seen the results (the area was only reopened to the public a few weeks ago), but it will be hard to do so for a while. Fortunately (and with good planning) the predator-proof area for threatened species in the north of the forest - see earlier in this post - was not directly affected by the fire.

Here are a few animals we eoncountered over the years - nothing particularly unusual, but they're all worthy of note.

Lace Monitors Varanus varius are common in dry forests and woodlands. They
do go further inland than this, especially along water courses, but are not
as common there. This big chap was cooling off in a dam.

They are excellent climbers and investigate tree hollows for potential prey.
This one went up the ironbark trunk...

... and then came down again.

Peron's Tree Frog Litoria peronii is widespread in south-eastern Australia,
and its mad cackle is a familiar night sound.

Feral Pigs are of course an environmental problem anywhere in Australia.
This family was disturbingly undisturbed by us across the dam.

And a few common birds, but nonetheless worth presenting.

Collared Sparrowhawk Accipiter cirrocephalus, a fierce little bird-predator,
found throughout the country.

Noisy Friarbird Philemon corniculatus, a big (and yes noisy) migratory honeyeater.

Red-capped Robin Petroica goodenovii, a glorious tiny inland robin
(and a pretty sketchy photo!).

Male Rufous Whistler Pachycephala rufiventris, another common migrant
whose songs fill the drier forests and woodlands from spring to early autumn.

But I'm going to finish with some plants, because the flowers in spring and autumn really are a delight in the Pilliga. Many of these species are found widely in sandstone and sandy soils of the western slopes, however I'm going to start with one which is a Pilliga endemic, and not very common even there. We found this one - and most of the others here - along the cliffs above Dandry Gorge.

Hibbertia covenyana, which was only described in 1990 from plants
collected from the side of the Newell Highway.

Golden-top Wattle Acacia mariae, a NSW endemic found in woodlands in the
north-east quarter of the state. The Pilliga is a noted site for it.

Pilliga Wattle Acacia pilligaensis, originally described from the Pilliga,
but also found in sandy soils from Dubbo to southern Queensland.

Mudgee Wattle Acacia spectabilis (confusingly also called Pilliga Wattle),
found widely in dry forests and Callitris woodlands on the western slopes
of NSW and in south-east Queensland.

Spurwing Wattle Acacia triptera, a hard spiky wattle which grows in
sandy woodland and heathland west of the Divide in eastern Australia.

Whorled Zieria Zieria aspalathoides Family Rutaceae; like many Pilliga plants
this one is found more widely on the western slopes, though in this case
from Victoria to tropical Queensland.

Sandstone Boronia Boronia glabra Family Rutaceae; again found on sand or sandstone,
north from Grenfell into south-east Queensland.

Scaly Phebalium Phebalium squamulosum Family Rutaceae; grows on sandstone
throughout much of eastern Australia

Family Lamiaceae, a mostly aromatic family which includes many of the Mediterranean culinary herbs, is well represented.

Granite Mintbush Prostanthera granitica, a not particularly common shrub
which grows in scattered rocky situations (though not always granite) on
the western slopes. This one was at the Sandstone Caves.

Prostanthera howelliae has no common name that I'm aware of, so it is not abundant.
Another one seemingly restricted to sandstone soils of the slopes.

Chloanthes parviflora, another plant not common enough to warrant an accepted
English name. A similar distribution, though scattered, to several previous species.

Grooved Dampiera Dampiera lanceolata, Family Goodeniceae;
a familiar plant with a very wide distribution from northen NSW
to far western South Australia.

Purple Beauty Bush Dampiera adpressa, a much less common Dampiera
than the previous one.

Seven Dwarfs Grevillea (I love it!) Grevillea floribunda, a delightful
small shrub which is widespread on the western slopes.

Homoranthus flavescens, a lovely little shrub in the Myrtaceae family,
another restricted to sandy soils, but only in north-eastern NSW.

Small-leaved Daisy-bush Olearia microphylla is widespread in dry forests
from Canberra to southern Queensland.

Western Wedding Bush Ricinocarpos bowmanii, Family Euphorbiaceae,
scattered in dry forest across the inland slopes and onto the plains.

Narrawarra Burr Solanum cinereum Family Solanaceae (ie tomatoes, nightshades etc).
Pretty much confined to NSW, where it is widespread on the slopes. It is not
welcome in grazing country as it is toxic to stock.

Leafy Templetonia Templetonia stenophylla. Apparently scattered widely west of
the Divide, this one surprised me because the only other Templetonia I know
has bright red flowers!

I don't think I've taken enough photos to really show off the forest, but in many ways it's a subtle beauty which I must try harder to bring to life in future trips. I hope I've been able to do enough though to encourage you, next time you're driving up the Newell, to stop for a while in the Pilliga and have a look around. If you don't yet know it you might be pleasantly surprised.

Spring in the Pilliga. Pilliga Box over wattle.

NEXT POSTING THURSDAY 2 MAY

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Iridescence: living rainbows

A few years ago now, I talked about blue feathers (and other natural blues). The basis of blue in bird plumage has nothing to do with pigments, but everything to do with the physics of light. Very (perhaps too) simply, it involves structures, or layers of structures, in feathers or skin which reflect only wavelengths of light which we see as blue. If the structure of such a feather is damaged, it will usually appear a dull white. 

 

However there is another type of colouration which uses the same general principles. This is iridescence where a feather (for example) shines from one angle but not another, or gleams with one colour, then another with a shift of perspective. This is a crucial difference from the blue-feather light trick - the blue feather will always look blue from any angle, but iridescent ones can be dull black or the colour of the background feathers, or flash in a variety of coloured lights. Behind the precisely aligned layers of reflecting and refracting feathers is a simple layer of dark melanin; in fact you'll notice that quite a few of the examples that follow have their iridescence on a black feather base. Very nuanced aspects of the overlying layers can intensify or neutralise the iridescent impacts. An oil slick on water will produce the same effect, with light reflecting off both top and bottom layers which interfere with each other as the water ripples to create a rainbow effect - and 'iridescence' is from the Greek iris, a rainbow.

 

Here are some examples of the effect, via pairs of photos of the same bird taken only seconds apart..

Ruby-throated Hummingbird Archilochus colubris , Trilha dos Tucanos lodge, in the mountains
behind Sao Paulo, Brazil. It is as if the bird has suddenly flashed a light at us - or rather,
to the other Ruby-throats around. Hummers are highly possessive of a food source.

Pacific Black Duck Anas superciliosus, wing speculum. Many ducks have this patch of
iridescent feathers on the secondary feathers of the wing, here changing from blue-green
to purple in moments. This is the most familiar Australian duck,
which has adapted easily to urban park ponds.

Oasis Hummingbird Rhodopis vesper, Azapa, Atacama Desert, northern Chile.

Velvet-purple Coronet Boissonneaua jardini, Sachatamia Lodge, north-western Ecuador.
These photos show the iridescent more impressively than it probably looks - they
were taken on a sunless dull, rainy day which dulls the iridescent gleam.

A slight change of angle and the wing edges and thighs light up.

Purple-throated Mountaingem Lampornis calolaemus, Monteverde, central
Costa Rica cloud forest. Hummingbird names are really over the top,
but it's hard to be too cynical about them, especially when they suddenly look
like the next photo, again just seconds later.

And finally before we move on to individual examples of iridescent brilliance, here's a situation that I find especially dramatic. This time it's of two birds of the same species at different times, but the results from different lighting conditions is quite striking, and it's already one of the most striking birds in the world. This is the splendidly named Resplendent Quetzal Pharomachrus mocinno, a trogon from Central America and the national bird of Guatemala. These birds seen in the same light would look the same, but one is in shadow, the other in sunlight, and look at the difference!

Male Resplendent Quetzal in the dim light under the canopy in the cloud forest of the Savegre Valley
of the central ranges of Costa Rica. Each one we saw here looked the same, this rich gleaming blue;
we were astonished and initially perplexed after our previous experience with it.

Whereas this one nearby in the open (eating wild avocadoes) was brilliant green,
which is how the field guides portray them.

It is no coincidence that I chose four hummingbirds as illustrations of iridescence in action - they are probably the world leaders in bird iridescence, in terms of the number of species that flaunt it. I'm also hopelessly in love with them. However I'll now move on to some other bird families which also iridesce - it's a widespread phenomenon and the following representatives come from 20 quite different families. I hope that's not too much, but it's a really just a celebration of these birds and the fabulous forms that their iridescence can take. If you prefer you can just scroll through the pictures, read what you feel like, and hopefully feel as uplifted as I do while I'm selecting and sharing them. And on the off chance that you're not yet sated with hummers I'm going to offer some more just before concluding - and with great discipline and restraint I've limited myself to just eight!

 

The families are in random order, and I've chosen only one or two representatives.in most cases. Parrots don't feature heavily in this discussion, perhaps because most are already strikingly coloured and don't need extra bling. It's probably no coincidence that this one is very sombrely coloured and lives in a dully coloured environment.

 

Austral Parrot Enicognathus ferrugineus, Chilean Patagonia.
This the world's most southerly parrot, occurring down to Tierra del Fuego
on the very tip of South America. The iridescence on the head is
subtle, but doubtless shows better in sunlight.

Quite a few ducks, on the other hand (including the Pacific Black Duck shown above), are members of the iridescent club. Most use the black duck's wing speculum approach, but here's one that doesn't restrict itself to that.

Male wild Muscovy Duck Cairina moschata, Pantanal, south-western Brazil.

Sunbirds, as the Old World equivalent of hummingbirds (though not related) are unsurprisingly aficionados of iridescence, but I find I'm rubbish at getting decent photos of them. (I've tried to blame the birds but then heard mum's ghost muttering about 'poor workmen blaming tools', so I'll desist. It does make it a lot easier to make choices when most of the options are terrible!)

Beautiful Sunbird (and there's an unhelpful name!) Cinnyris pulchellus,
Serengeti NP, Tanzania.

Eastern Double-collared Sunbird Cinnyris mediocris Lake Nakuru NP, Kenya.

I wouldn't have thought of storks in this context, but a look at this pair's necks shows I'd have been wrong.

Pair of Black-necked Storks Ephippiorhynchus asiaticus, Norman River,
Gulf of Carpentaria, tropical Queensland.

Another group of large waders can be pretty flash at times too.

Hadeda Ibis Bostrychia hagedash, Uganda. This raucous ibis (from which it gets its name)
is common in sub-Saharan Africa, but its wing iridescence isn't often remarked upon.

Nor are Australian ibises lacking in this department.

The Glossy Ibis Plegadis falcinellus, here in Canberra where it's a rare visitor, is an obvious
candidate; it is widespread in Africa and Australia and scattered in Asia and the Americas.

However the Straw-necked Ibis Threskiornis spinicollis, abundant in Australia,
isn't so often cited as iridescent, though the whole wing can shine on occasions.

Likewise we don't often think of finches (ie family Fringillidae, rather than the grass finches of Africa, southern Asia and Australia) as iridescent either, but some of the Neotropical euphonias and chlorophonias certainly qualify.

Chestnut-bellied Euphonia Euphonia pectoralis, Trilha dos Tucanos lodge,
in the mountains behind Sao Paulo, Brazil

The starling family, on the other hand, is replete with iridescence; here are some representative species.

Superb Starling (sometimes dubbed 'superstar') Lamprotornis superbus, at the breakfast table,
Buffalo Springs Reserve, northern Kenya. That glowing necklace compensates for its cheek.

Rüppell's Starling Lamprotornis purpuroptera, Serengeti NP, Tanzania.

Metallic Starling Aplonis metallica, Cairns. Australia' only native starling, and
its ancestors only arrived recently. A shining (albeit rambunctious) beauty.

Quite a few swallows also catch the light beautifully.

Pacific Swallow Hirundo tahitica, Sabah, Malaysian Borneo.

Ethiopian Swallow Hirundo aethiopica, northern Cameroon.

Some cuckoos carry their iridescence in their names, but those are not the only ones to shine.

Shining Bronze-Cuckoo Chrysococcyx lucidus, Canberra.

Pacific Koel Eudynamys orientalis, Canberra (taken from my driveway in fact).
Sometimes we get so caught up in its insistent all-hours calling, or its
breeding habits (here it exclusively parasitises Red Wattlebird nests)
that I think we forget just how beautiful a bird it is.

The mostly Neotropical tanagers are among the most colourful groups of birds in the world, but some of them gild the lily with some iridescence thrown in as well.

Saffron-crowned Tanager Tangara xanthocephala near Machu Picchu, Peru.

 

Ruby-crowned Tanager Tachyphonus coronatus, inland of Sao Paulo, Brazil.
This beauty is restricted to the highly threatened Atlantic forests of eastern Brazil.

 

Masked Flowerpiercer Diglossa cyanea, Yanacocha Reserve
near Quito, Ecuador. Not all tanagers have 'tanager' in the name
(and some 'tanagers' are actually something else, but we won't go there!).
This group makes a living by punching a hole in the base of a flower and
'stealing' the nectar without pollinating.

From now until the big hummingbird finale, I'm only going to offer one glossy example per family; after the hummingbirds' return appearance I'll be ending with four Australians.

Yellow-fronted Woodpecker Melanerpes flavifrons, another from the wonderful
Trilha dos Tucanos lodge in the Atlantic forests near Sao Paulo. I've not noticed
iridescence in many woodpeckers, but this one qualifies.

Green Wood-hoopoe Phoeniculus purpureus, Lake Nakuru NP, Kenya.
This belongs to a small African family, not hoopoes though they are in the same suborder.

Here's another from the same Order, though a different Family again.

Oriental Pied Hornbill Anthracoceros albirostris, Sabah, Malaysian Borneo.
Another group that I don't normally associated with iridescence but
I find that the more I look the more I find!

I'd not have thought that kingfishers would generally need any help to look gorgeous,
but this tiny Malachite Kingfisher Corythornis cristatus at Lake Mburo NP, Uganda,
has beautiful glowing spots on head and wing edges.

Pitta-like Ground-roller Atelornis pittoides, Ranomafana NP, Madagascar.
Bad photo but a tricky bird and the best I could do - I'm privileged to have
even seen it. This small family is endemic to Madagascar.

As promised/threatened, here are some more iridescent hummingbirds (and you can't imagine how many I've left out!). I don't think they need much commentary from me.

Blue-mantled Thornbill Chalcostigma stanleyi, El Cajas NP, southern Ecuador,
at 4000 metres above sea level.

Fiery-throated Hummingbird Panterpe insignis, central ranges, Costa Rica.

Green-crowned Woodnymph Thalurania colombica, Tandayapa Valley, north of Quito, Ecuador.

Lesser Violetear Colibri cyanotus, Monteverde, Costa Rica.

Long-tailed Sylph Aglaiocercus kingii, on the eastern slope of the Andes in
northern Ecuador. There is a sister species on the western slopes.

    Purple-bibbed Whitetip Urosticte benjamini, Tandayapa Valley, north of Quito, Ecuador.

Stripe-tailed Hummingbird Eupherusa eximia, Monteverde, Costa Rica.

Violet-bellied Hummingbird Chlorestes julie, Umbrellabird Lodge, southern Ecuador.

I do hope that wasn't too tedious! :-) And finally, some Australians who iridesce.

Satin Bowerbird Ptilonorhynchus violaceus eating Lilly Pilly berries,
National Botanic Gardens, Canberra.

Shining Flycatcher male (she is chestnut and white) Myiagra alecto,
Kakadu NP, Northern Territory.

Spangled Drongo Dicrurus bracteatus, Canberra (just round the corner in fact);
this one of only two I've seen in Canberra in over 40 years, though they are
common further north.

Splendid Fairywren Malurus splendens, Gawler Ranges, South Australia.
Splendid as he is, he's not yet finished moulting into his full summer beauty.

And that's it for a somewhat extended investigation of iridescence in birds from around the world. It's worth keeping an eye open - there's more of it about than you might expect. Thanks for reading this far, it's been quite a journey.

NEXT POSTING THURSDAY 11 APRIL

I love to receive your comments and in future will be notifying you personally by email when a new posting appears, if you'd like me to. All current subscribers have been added to this mailing list and have already been contacted. This will mean one email every three weeks at the current rate of posting. I promise never to use the list for any other purpose and will never share it.
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