About Me

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Canberra-based naturalist, conservationist, educator since 1980. I’m passionate about the natural world (especially the southern hemisphere), and trying to understand it and to share such understandings. To that aim I’ve written several books (most recently 'Birds in Their Habitats' and 'Australian Bird Names; origins and meanings'), run tours all over Australia, and for the last decade to South America, done a lot of ABC radio work, chaired a government environmental advisory committee and taught many adult education classes – and of course presented this blog, since 2012. I am the recipient of the Australian Natural History Medallion, the Australian Plants Award and most recently a Medal of the Order of Australia for ‘services to conservation and the environment’. I live happily in suburban Duffy with my partner Louise surrounded by a dense native garden and lots of birds.

Thursday, 19 April 2018

Cocopara National Park; a little beauty

In our part of the world, every Easter (and at other holiday times) large numbers of our fellow Canberra citizens head east to the coast. We're not keen on crowds, so this year we opted to go west instead, through the woodland remnants of the deep soils of the South-west Slopes region to the edge of the great Western Plains, which effectively roll flatly on until they reach the Indian Ocean, almost 3000km away. Our goal was to spend three nights camping in Cocoparra National Park, in a low range near the irrigation town of Griffith in the Riverina region.
Our Cocoparra home for three days; despite it being Easter there were never more than two or three other
camps in the Woolshed Flat Campground at any time, scattered over a large area.
This is a low rainfall area, and it has been a particularly dry summer, as the photo suggests.
Griffith (and Cocoparra) are at the end of the red arrow.
When the (notoriously gloomy, as reflected in his diaries) Surveyor-General John Oxley entered the land of the Wiradjuri people in June 1817 he was, predictably, not impressed. Of the plains, supporting dry woodlands and mallee shrublands, he commented: “There is a uniformity of barren desolation of this country which wearies one more than I am able to express.” Of the view from the ridge of Cocoparra (which he called Peel's Range) he opined: “I am the first white man to see it, and I think I will be undoubtedly the last.” He continued that theme when, to mark the king's birthday, they planted oak, apricot, peach and oak seeds in the range (well, he was an surveyor, not a horticulturalist) and he sniffed that the act was "to serve to commemorate the day and situation, should these desolate plains be ever again visited by civilised man of which, however, I think there is little probability". Perhaps not someone you'd invite twice to dinner.

I can't judge whether they were civilised people, but Europeans certainly did come and settle, albeit some 50 years later, taking up the land surrounding the range as huge grazing properties, which were later subdivided into wheat farms in the early 1900s. Meantime, not far to the west, a massive irrigation scheme, planned in the late 19th century and activated in the early years of the 20th, was transforming the plains, bringing water from new distant reservoirs on the Murrumbidgee River. The rich soils lacked only water, and with that they now produce huge quantities of grapes, citrus, stone fruits, olives and vegetables. 
Looking west over the plains from Cocparra to the McPherson Range, at the foot of which lies Griffith.
Black Cypress Pine Callitris endlicheri dominates the foreground.
The two ranges comprise 350 million year old sandstones and other sedimentaries, laid down on an inland floodplain.
Folding and uplifting have raised the ranges above the much newer soils which filled the basin between them.
Fortunately for us, none of this affected the Cocoparra Range much; there was some opportunistic grazing, but in general the slopes and gorges were too rough for stock. In acknowledgement of this (plus, we hope, because of the undoubted biodiversity values of the range) it was declared a national park in 1969, nearly 50 years ago. It covers only 8300 hectares, though is supplemented by the 4600 hectare Cocoparra Nature Reserve adjoining to the north (a nature reserve is dedicated wholly to conservation and research, not passive recreation, which is a function of national parks). 
Welcome to Cocoparra National Park!
As I suggested earlier, it was dry while we were there; average annual rainfall is only 400mm anyway, but there have been only 25mm so far this year, and only about 5mm since the beginning of February. Normally the rain is divided pretty evenly between all 12 months. The trees and shrubs and resident animals are quite capable of dealing with such conditions, but there was almost no flowering and very few herbs. As we would expect, the vegetation on the hills is very different from that on the lowest slopes and valleys. As seen in the previous photo, Black Cypress Pine is an important component on the hillsides and ridges.

Black Cypress Pine, Jack's Track.
This is one of our favourite walks in the park, which starts on the exposed slopes and ends by descending
into the gorge of Ladysmith Glen; several of the photos here were taken on that walk.
(And just after this photo I was concentrating so much on the trees and possible birds that I managed to
completely overlook the Eastern Brown Snake - generally listed as the second most venomous snake in the world -
that was crossing the track. Fortunately for all concerned I failed to step on it, but Lou, immediately
behind me, was less than sanguine about the episode, which I can fully understand...)

Currawang Acacia doratoxylon. This tall spindly wattle forms dense stands on ridges in particular.
It is also known as Spearwood Wattle - which is the meaning of the species name too - presumably
for a recorded use by the Wiradjuri.
Dwyer's Gum Eucalyptus dwyeri. One of the red gum group, which grows almost
exclusively in rocky situations. In particularly harsh positions it will grow as a mallee form -
ie a multi-stemmed shrub sprouting from a subterranean lignotuber.
 On the deeper soils different trees predominate.

Mugga Ironbark Eucalyptus sideroxylon, with White Cypress Pine Callitris columellaris on the left.
The deeply fissured bark is impregnated with kino, and as it dries out becomes immensely hard.
There are a few dozen species with this characteristic scattered across eastern Australia.

Bimble Box Eucalyptus populneus. This lovely tree is characteristic of the NSW western plains, and
north into Queensland. The shiny rounded leaves give rise to the species name, meaning 'poplar-like'.
And in the few creekbeds - which are dry most of the time - are found the ubiquitous River Red Gums Eucalyptus camaldulensis, which dominate every stream line in inland Australia.
River Red Gums in Jacks Creek Gorge (also known as Ladysmith Glen).
This is a lovely little gorge; I've seen it with substantial pools and calling frogs, but more often I've seen it as we did this time, with no surface water, though the gums are tapping into the water below the sand. I always pause at the lookouts above the gorge before descending.
Looking down into Jacks Creek Gorge (Ladysmith Glen).

Crumpled sandstone layers on the opposite wall.
The creeper on the rocks is Wonga Vine Pandorea pandorana, Family Bignoniaceae.
The lovely tube-shaped flowers of Wonga Vine (from a previous visit).
Remarkably, this species is found in most habitats in all mainland Australian states, and beyond to
New Guinea, Vanuatu and Indonesia.
Peregrine Falcon roost (and possibly nest) in the gorge. I've seen them send the local Galahs into
frantic panic here, but they didn't appear this time.
Which brings us to a few of the birds of Cocoparra; most of the following were taken around the camp ground.
Bar-shouldered Dove Geopelia humeralis.I was surprised to hear the distinctive "let's go to schoooool" call
as soon as we arrived, and the pretty doves were all around.
'Surprised' because this is much more a coastal and northern species, though they turn up sporadically inland.
Male Mulga Parrot Psephotellus varius, one of our loveliest parrots (in my opinion at least!)
and found throughout much of Australia's drylands.
Ringneck Parrot Barnardius zonarius, above and below.
Another parrot with a very wide inland range, and several distinct subspecies.

Jacky Winter Microeca fascinans, one of the fly-catching Australian robins,
though without the usual red or yellow undersides it is not always recognised as such.

White-browed Babbler Pomatostomus superciliosus, the smallest of the four Australian babblers
(there is also one in New Guinea). I love these bold raucous highly sociable larrikins bouncing across the
ground and cramming into a roost nest. They used to be placed with the old world babblers (hence the name)
but are now put in their own family, with just the one genus.
Female Splendid Fairywren Malurus splendens. The family was swarming across the campground in the early
morning (see the angle of the sun), but she insisted on staying between me and the sun.
The male had already moulted out of his glorious breeding plumage.
Speckled Warbler Pyrrholaemus sagittatus, in Deane's Wattle Acacia deanei.
White-eared Honeyeater Nesoptilotis leucotis, gleaning insects above our camp.
Wedge-tailed Eagle Aquila audax; this beauty was perched by the road as we drove
out of camp on the first morning.
It was a good three days, starting with the sun warming the nearby low sandstone cliff...

... ending with the rising moon and stars shining through the Bimble Box...

... and getting up at night under the Southern Cross.

Camp out soon if you can possibly do so - most of us do far too infrequently for our own good. And if you can possibly drop in on Cocoparra sometime, that would be doing yourself a favour too.

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Thursday, 12 April 2018

Crocodiles and Alligators; never smile, see you later...

Few reptiles exert the same (often horrified) fascination for people as do crocodilians - and I'll explain shortly why I'm using that apparently fussy and precious term instead of just 'crocodile' when talking about the overall group.  Like sharks, it seems that they are in such control in the water, where we are inevitably just visitors. We can't learn to 'read' a crocodile as we might a predatory mammal. As an excellent South African wildlife guide, who'd spent his life in the African bush, put it to me: "you can negotiate with a lion, you can't negotiate with a crocodile". (Not that I'm interested in trying either of course!)
Big male Estuarine Crocodile Crocodylus porosus crossing the Daintree River, north Queensland.
We were in a boat (large enough for us to feel comfortable!), and he definitely turned towards us
for a look, before continuing on his way.
This magnificent predator is the largest of all living reptiles.
The crocodilians comprise an Order (Crocodilia) within the Class that represents reptiles.(The other vertebrate classes represent mammals, birds, amphibians and fish, but as ever there's a complication. The fact is that crocodilians are more closely related to birds than they are to lizards - both crocodilians and birds are direct descendants of dinosaurs, while lizards are not. Given this, there has for a while now been a somewhat robust discussion about the apparent unravelling of logic here; either crocodiles should not be described as reptiles, or birds should. The latter position is favoured by quite a few respected voices, but for now I'll leave you to angst over it - sorry about that! - and return to our more immediate subject.)

There are three Families of crocodilians - the crocodiles (hence my use of 'crocodilian' for the overall group), the alligators and caimans, and the single-species Family represented by the Indian Gharial.
Gharial Gavialis gangeticus, Uttar Pradesh, India.
(Photo courtesy Wikipedia.)
This narrow-jawed fish-eating specialist is, tragically, Critically Endangered.
For the rest, there are 14 species of crocodile (four each in Africa and the Caribbean/Central/South America region, and six from Australia through south-east Asia to India), and 8 caimans and alligators (the six caimans are all South American, and there is an alligator in both the south-east USA and in China, where it is seemingly headed for extinction).
Nile Crocodile Crocodylus niloticus, Queen Elizabeth National Park, Uganda.
This species is second in size only to the Estuarine Crocodile.
The scales typical of all crocodilians are evident here; this tough waterproof outer layer forms as the skin cells
cornify, ie they die and fill with keratin. On them are rows of hard separate scales.
The powerful laterally flattened tail sweeps from side to side to drive the animal through the water.
Yacaré Caimans Caiman yacare, Pantanal, south-western Brazil.
The concentration of this species in the vast ephemeral wetlands of the Pantanal, estimated at some ten million caimans,
is the greatest in the world.
There is plenty of - often superficial - discussion of the differences between crocodiles and alligators out there, so I won't spend a lot of time on it here. Inter alia, in the wild it is only relevant in the Caribbean region, but the discussion can still raise some interesting points. One observation often made is that alligators/caimans have a broader 'U-shaped' nose, compared to the sharper 'V-shaped' nose of the crocodiles. I would add a large 'but' to that assertion, though it is generally true. You can see the narrower snout in the Nile Crocodile above, and in this Freshwater Crocodile C. johnsoni.
Freshwater Crocodile, Boodjamulla (Lawn Hill) NP, north-west Queensland.
This relatively small species mostly eats fish, and its narrow jaws (like that of the Gharial) are probably
adapted for quick movement rather than power.
This Black Caiman Melanosuchus niger and the following Yacaré Caiman display the 'typical' short broad alligator snout.
Black Caiman, Rio Madre de Dios (Tambo Blanquillo Lodge), southern Peruvian Amazonia.
Yacaré Caiman, Pantanal.
It has been claimed that this shape is an adaptation to crunching up hard turtle shells, but I've seen little evidence either that this jaw shape allows a more powerful bite than a longer more tapering snout, or that alligators and caimans eat significantly more turtles than do crocodiles. Moreover it also seems to be, in part, a function of age. As the big crocodiles age, their jaws get blunter and more massive.
Big Estuarine Crocodile (in captivity, Territory Wildlife Park, south of Darwin).
And here's a young caiman.
Spectacled Caiman Caiman crocodilus, Yasuní NP, Ecuador.
Probably a more reliable indicator is in our view of the teeth when the jaws are closed. An alligator/caiman's upper jaw is broader than its lower one, so the lower teeth tend not to be visible from side on.
Yacaré Caiman, Pantanal. Toothy enough - but only the top teeth.
On the other hand a  crocodile's jaws are roughly the same width, so top and bottom teeth intermesh, and some at least of the bottom teeth are also on view; in particular, there is a very large fourth (from the front) bottom tooth, which apparently could not comfortably fit inside the mouth, so rests in a skin indentation outside the top jaw, just behind the nostrils. This early morning sun-bathing beauty demonstrates this feature admirably.
Estuarine Crocodile, Kakadu NP, Northern Territory.
The origin of the idea of the famous crocodile 'smile'.
Recent Japanese research may have thrown up another consistent distinction too. Crocodiles have consistently longer 'upper arm bones' (humerus) and 'thigh bones' (femurs) than alligators, though this is not a very useful field character... However it does raise another issue that distinguishes crocodilians from 'other reptiles'. Their legs are structured in a way that enables them to stand high off the ground with their legs directly under them, and ankles that enable the feet to swivel, giving a walk unlike that of any other reptile, but not dissimilar to that of mammals. 
Crocodile legs, modelled by Estuarine Crocodile, Territory Wildlife Park, NT (above),
and Freshwater Crocodile, Katherine Gorge, Nitmiluk NP, NT (below).
Note that only the hind feet are webbed.
This species in particular is known to gallop across the ground.
One was measured at 17kph, the world land speed record for a crocodile!
Another generalisation sometimes encountered is that crocodiles are larger than alligators. While it is true that the largest alligators are somewhat smaller than the largest crocodiles (some living Estuarine Crocodile are over six metres long and weigh more than a tonne), they are also much larger than most crocodile species. While decades of over-hunting in northern Australia brought numbers very low, they are rapidly recovering under protection which was imposed in 1971; however they are slow-growing and it will be some time before we can test the stories of huge crocs of the past. Perhaps the best-known of these is celebrated in a supposedly life-sized statue in Normanton, north Queensland, near the Gulf of Carpentaria.
The truly magnificent animal which this statue claims to faithfully represent was 8.6 metres long and weighed
over two tonnes. It was shot on the banks of the nearby Norman River in 1957 by Krystina Pawlowski,
a Polish post-war immigrant. Her story (and that of her husband Ron), and their later conversion to campaigners
for crocodile conservation - and subsequent harassment by the Queensland government - is well worth reading.
Here's one version of it; I understand that all the essential elements of it are true.
Black Caiman, Manu River, southern Peruvian Amazon. I estimated this huge caiman to be
at least four metres long. Like the big crocodiles they are apex predators, though fish are their main prey.
In recent years I've noted that Amazon lodges are increasingly banning swimming in their lakes;
discreet enquiries by our guides have revealed some serious attacks on tourists which were not widely reported.
Wherever really big crocodilians are present, they are the top predators in their environment. (Crocodilians in fact are the only group of exclusively carnivorous reptiles.) With smaller species and individuals, there is more of a balance. In the Pantanal, Jaguars prey heavily on Jacaré Caimans; in Amazonia, Black Caimans and Giant Otters are permanently at war, each preying on the young of the other. In Australia Estuarine and Freshwater Crocodiles can coexist in inland waters - despite their name the Estuarines are quite at home in fresh water - but 'freshies' generally avoid 'salties', doubltess aware of the real hazards posed by their big relations.
Yacaré Caiman with big catfish; piranhas are probably the biggest prey item for them however.
Some aspects of crocodilian breeding seem universal, with a male controlling a territory containing several females; eggs are bird-like, with hard calcium carbonate shells (unlike reptiles). However strategies vary around this theme. For instance in Australia Freshwater Crocodiles dig out a hollow in a sandbank near the water and lay about a dozen eggs. She doesn't guard the eggs, and many are taken by goannas, but when the hatchlings start calling (before hatching) she comes and digs them out and carries them to the water. Estuarine Crocodiles on the other hand build a mound of mud and vegetation, in which she lays around 50 eggs, which she defends against predators - very few goannas manage to rob their nests. Estuarine mothers too are attentive, guarding their young for months.

(Empty) Estuarine Crocodile nest, Kakadu NP, Northern Territory.
Ancient Gondwanan crocodiles known as Mekosuchines arose some 50 million years ago, and survived in inland Australian in and around swampy areas, but most died out as Australia dried, by the end of the Pliocene 1.6 million years ago. However one genus, Kwinkana, a big long-legged terrestrial hunter, survived well into human times; as ever it is impossible to say whether humans or climate change finished it off. However modern crocodiles (Crocodylus) apparently only arrived in Australia recently, as the continent drifted north into Asia. Estuarine Crocodile are great seafarers, using ocean currents, and would have had no problem island-hopping as Australia approached Indonesia. (Inter alia it's a very short hop from eastern New Guinea to Cape York.) I am not aware of any genetic studies, but I assume that Freshwater Crocodiles evolved from these immigrant salties.

Perhaps I've not encouraged many people to love crocodiles - and I don't imagine the crocodiles want that anyway! - but I hope you can appreciate these venerable consummate hunters a little more now. Let's end on some crocodilian portraits from across the southern hemisphere.
Estuarine Crocodile cruising past a Striated Heron, East Alligator River, Kakadu NP.
Estuarine Crocodile, Kinabatagan River, Sabah, Malaysian Borneo.

Nile Crocodile and Cape Buffalo, Queen Elizabeth NP, Uganda.

Baby Spectacled Caiman, Yasuní NP, Ecuador.

Spectacled Caiman at night, Yasuní NP, Ecuador.

Yacaré Caiman and Capybara, Pantanal, Brazil.

Yacaré Caiman crossing the road, Pantanal.
Yacaré Caiman with headwear, Pantanal.
Estuarine Crocodile in the landscape, Cooinda, Kakadu NP.
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