Northern Territory Wildlife Park; the wild side

Having just returned from a week and a bit based in Darwin at the very northern end of central Australia (and having organised my photos) it's inevitable that this wonderful tropical part of the world should feature today. Some people considered us mad for visiting during the 'Wet' (or the 'Green Season' as the tourist industry has taken to preferring!) and while they may have a case, we loved it. It doesn't rain all the time, though impressive storms featured late on most days, and while it's of course humid the temperatures were surprisingly mild - no more than about 33 degrees.

Darwin, capital of the Northern Territory, at the end of the red arrow.
We live a bit over 3000km away (and some 2600km to the south) at the end of the green arrow.

One 'must visit' destination for any visitor is the magnificent Territory Wildlife Park (the 'Northern' is apparently considered superfluous!), 60km south of Darwin. Technically I suppose it is a zoo, but that conjures up images quite misleading in this case. Founded by the territory government in 1989, it is set in 400 hectares of natural habitat, of which only a tiny proportion is developed. A four kilometre circuit track is regularly travelled by a little train (not on rails) driven by informative guides and is paralleled by walking tracks which also branch off into the bush. Features include a series of habitat-based aviaries, culminating in a huge and magnificent aviary featuring the monsoon forest; an aquarium including a walk-through tunnel with animals swimming by and over you; a nocturnal house, and daily educational displays of free-flying birds. All are well done, and the educational and conservation themes are powerful.

However I want to feature today 'the rest' - the huge area of the park which is outside the developed sections, accessed by the walking track system. There are three basic habitat types represented within the grounds; dry woodland, monsoon forest and wetland systems, though each can be further sub-divided. 

Dry eucalypt woodland, the dominant vegetation type of the Top End.
Above, featuring 'Screw Palm' Pandanus spiralis,and below the cycad Cycas armstrongii; both are common understorey components.

'Screw Palms' are of course not palms at all - monocots certainly, but in the family Pandanaceae. The leaves
are spirally arranged on the trunk, and their bases form the distinctive stem spirals when they drop.
Indigenous culture is alive and well in the Top End, and this plant is very important to the original Territorians: it provides food from seeds, fruit and stem; medications; fibre for mats, baskets and rope; wood for drum sticks and rafts.

Monsoon Forest (above and below), or Vine Forest, is a type of dry rainforest, occurring in
isolated patches across the Top End, especially nearer the coast. Away from the coast, where rainfall
is often lower, it tends to be found around streamlines (below).
There is no true ('wet') rainforest in the Top End because winter rainfall is too low to sustain it.

Wetlands comprise open water and their fringing vegetation, plus surrounding areas of paperbark (Melaleuca spp.) swamp woodland which may be inundated for weeks or more every year.

Goose Lagoon (above) and associated paperbark swamp (below).

 

The rain didn't disappoint us either. On the one occasion we travelled a section in the little (open-sided) train it bucketed down, and as we cornered a gush of water from the roof filled the curved plastic bench sit beneath us. We naturally leapt up - and were politely but firmly requested by the driver-guide to sit down again! Oh well, it was a warm pool to sit in at least.

Tropical rain in the Park.
The attractive but bedraggled centipede (below) shared our shelter; I'm afraid poor light and
its haste to escape make for an inadequate photo.

 

Which brings us to the many wild animals which dwell within the park boundaries. One of the apparently counter-intuitive aspects of the Wet is that water birds are far harder to find than in the Dry. It makes sense of course - with water across ten of thousands of square kilometres of country the birds are scattered across the plains. However even now there are some to be found around the park's wetlands.

Australian Pelicans Pelecanus conspicillatus.

The eponymous geese of Goose Lagoon. Magpie Geese Anseranas semipalmata are widespread
across northern Australia. They are neither goose nor duck, but the sole living member of an ancient
family which predates all current ducks, geese and swans. One distinguishing characteristic is the partially
webbed toes (from which derives the species name).

Radjah Shelducks Tadorna radjah are well within the mainstream of duckdom -
and in my opinion are one of the most beautiful ducks in the world.

Forest Kingfishers Todiramphus macleayii are another spectacularly beautiful component
of tropical Australian birdlife; they are members of the tree kingfisher family.

Orange-footed Scrubfowl Megapodius reinwardt.These relatively small megapodes - mound-builders - build huge incubating mounds for their eggs.
This is the only one of the three Australian species to be found in the Top End where they are widespread.
They can be encountered anywhere in the park.

The Varied Triller Lalage leucomela is another common Top End bird, but also found throughout
the near-coastal tropics and down the east coast almost to Sydney. Its melodious call is
part of the musical sound track of the park.

Agile Wallaby Macropus agilis, the commonest wallaby of northern Australia.
You can't afford to live up here if you can't cope with wet feet and a bit of rain!

This Javelin Frog's (Litoria microbelos) luck changed for the better when we arrived at the Goose Lagoon
bird hide. It was being seriously molested by a trio of Green Tree Ants and launched itself at me when I appeared.
The ants were dislodged and I placed it on a post outside (below) from where it could jump into the water.
It was still being stalked however...

 

Reptiles are always present in the Top End, and the Wildlife Park is no exception.

Slender Rainbow Skink Carlia gracilis. This is a breeding male; only they develop the spectacular
blue-green head and bright chestnut sides.

Yellow-spotted Goanna Varanus panoptes; originally in this posting I had misidentified it as the locally commoner Mertens' Goanna V. mertensi. My thanks for Wildlife Park staff Alice Anne Body and Dion Wedd for taking the trouble to contact me and point out my error. The transverse bands of conspicuous dots are one characteristic I should have recognised. Both these goannas are nowhere near as common as they used to be before the arrival of the
toxic introduced Cane Toad Bufo marinus.

So, when you go the Top End, whatever the season you must visit the Territory Wildlife Park; when you do so don't miss the aviaries and aquariums, but equally importantly don't miss the wealth of life going about its wonderful business outside the developed sections. This is the Top End concentrated!

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Kurrajongs and Bottle Trees

With a title like that you might reasonably suspect a joke on my part, but in fact this is the latest in my sporadic series on favourite trees; you can find the most recent instalment here and find earlier ones from there if you so wish.

I grew up with some of the Australian children's classics, including May Gibbs' Snugglepot and Cuddlepie series, very whimsical (and somewhat downright scary) and very Australian, with the characters based on bush flowers and fruits. I'll leave you to investigate further if it's new to you, but one thing that always intrigued me was their use of Kurrajong pods as boats. In Adelaide we didn't know Kurrajongs, but when I moved to eastern Australia I was delighted to get to know them, and the members of the genus Brachychiton are now among my favourite trees. Around Canberra and onto the western slopes Kurrajong B. populneus grows in a range of drier situations from rocky hillsides to deep plains soils. (The myth that Kurrajong indicates the presence of limestone appears to be just that.)

Kurrajong near Molong, New South Wales.
A lovely spreading tree with soft glossy green foliage that shines in the breeze.

The seed pods, the May Gibbs boats of my childhood reading, contain stinging hairs,
but the seeds if winnowed can be roasted and used in a beverage.

The genus name Brachychiton translates as a short Ancient Greek tunic, in somewhat whimsical reference to the loose covering of the seed. Populneus is a reference to the supposedly poplar-like nature of the foliage.

Kurrajong leaves; the three lobed form is often a character of younger trees. These leaves are quite soft,
unexpectedly so for an Australian dry country plant.

The foliage is a reason that Kurrajongs are often left in otherwise largely treeless rural landscapes; the leaves are valuable drought fodder and branches are cut in hard times to feed sheep and cattle. The tree recovers. 

The palatability of the leaves can be readily deduced when a Kurrajong grows on a fence line.
Outside the fence (on the left) the foliage sweeps down to the ground; inside stock have
browsed it as high up as they can reach.

The origin of the word Kurrajong itself is somewhat confused. It seems that it is probably one of the few words remaining of the language of the people who lived where Sydney now stands; their name or language might have been Dharug, as is often asserted, but not all experts are convinced. However the word seems to have referred to a fibre used for lines or fishing nets, and deriving from a native Hibiscus (H. heterophyllus). Somehow the word got to be used for 'our' Kurrajong, which grew on the Cumberland Plain to the west of Sydney. It has also been applied at times to species of Pimeleas which, like the Kurrajong, were also valued for their fibrous bark. Too often we didn't pay enough attention to what we were being told and I've wondered if many of our forebears merely confused the word for the fibre with the various plants it derived from.

However the Kurrajong is just one of 31 Brachychiton species, all of which are Australian but for one New Guinea species. Until 2006 they were broadly accepted as being in the family Sterculiaceae, but then a detailed genetic study determined that Sterculiaceae was really an artificial family, and most of its members (along with those of other related families) were moved into the hibiscus family, Malvaceae. That seems to have since been generally accepted.

The flowers are distinctive - and not very reminiscent of hibiscus, it must be noted. They comprise a tube of fused sepals (not petals, it seems, despite their colouration). 

Kurrajong flowers, Pilliga National Park, New South Wales.

Others are more brightly coloured.

Red-flowered Kurrajong B. paradoxus, Litchfield National Park near Darwin.
A small tree of the tropics.

Flowers of Illawarra Flame Tree B. acerifolius carpeting the forest floor, Chichester State Forest, New South Wales.
Like other forest species, this one is deciduous, flowering after the leaves have dropped,
producing a spectacular effect.

At the other habitat extreme from the wet forest Flame Tree, there is a Brachychiton native to the harsh central deserts too.

Desert Kurrajong B. gregorii, Mereenie Loop, central Australia.
The species name is for Augustus Gregory, the explorer who collected the type
specimen far to the west on the Murchison River in 1848.

Desert Kurrajong fruit - the close relation with Kurrajong is obvious.

Perhaps the most widely recognised member of the genus however is endemic to inland south-eastern Queensland. The Queensland Bottle Tree is instantly recognisable by its oddly bulbous trunk at its mid-height, which intrigued the explorer Thomas Mitchell when he encountered it near where Roma now stands in 1848 (coincidentally the same year that Gregory discovered the Desert Kurrajong on the far side of the country). He considered, understandably, that it "looked very odd".

Queensland Bottle Tree B. rupestris near Tambo.
However, Kath has kindly commented below that she thinks this could be Broad-leaved Bottle Tree, B. australis,
which isn't as massive as B. rupestris. I'm not in a position to disagree (see my comments
below hers) and she could well be right.

The landscape dotted with these magnificent trees makes the drive through central Queensland worth it just for that. (And incidentally they are not at all the same as the Baobabs of north-western Australia, Madagascar and Africa, though the recent taxonomic revision has put them into the same family.) They dominate now scarce and threatened vine scrub habitats.

Queensland Bottle Tree (this one I am sure of) dominating vine scrub at
Lake Nuga Nuga NP, Queensland.

Several species, especially tropical ones, are deciduous in the dry season.

Broad-leaved Bottle Trees B. australis, leafless in winter, Undara NP, north Queensland.

My love affair with kurrajongs and bottle trees is not wholly platonic - our relatively small front and back yards host a Kurrajong and Queensland Bottle Tree respectively, and they're showing every sign of returning our affection by thriving.

I hope you can share my enthusiasm for them.

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I Come, I Soar, I Conquer

It's been a while now since I waxed lyrical about the amazing spin-off of flight called hovering. It is an extraordinary achievement, but there is another extreme to flying that only a very few species have ever achieved. 

Female Magnificent Frigatebird Fregata magnificens, Galápagos.
She accompanied our boat (with many companions - see below) for kilometres,
and I don't recall once seeing her flap.

Strictly, she was not flying, but soaring. Perhaps this is being a bit precious, but it does seem important to make the distinction or we'll miss out on understanding this extreme of flight. Flying is, in technical terms, 'assisted aerial motion', which can also be stated as 'flapping your wings'. You need to be able to flap fast enough to overcome the drag of air along and behind your body. To accelerate or climb you must flap even faster still. 

Soaring however, as I observed in the caption above, involves not flapping your wings. The energy in this case comes from the air around you, which may be deflected up (eg from a boat pushing through it, or from an air mass moving over a ridge-line or a mountain) or from rising thermals of warmed air, over a sand dune or even a city. The frigatebirds were using this energy to move forwards; birds which rise on a thermal can then soar for tens or even hundreds of kilometres, losing height only incrementally as they go. In any case, as you could imagine, very complex and precise adaptations of both physiology and shape are required; it seems that only some larger birds and pterosaurs have ever mastered the art. (I should emphasise that pterosaurs had no connection to birds; they were reptiles of an entirely different line from the dinosaurs which gave rise to birds. Or perhaps I should say the group of living dinosaurs that we call birds.)

Mathematically, the best shape for a soaring wing is the one exhibited by the frigatebirds above; it is very long and slender and pointed, and known in the trade as a 'high aspect ratio' wing. Aspect ratio is defined as wingspan squared divided by wing area - in other words a high aspect ratio means a very low wing loading, or very little weight per square centimetre of wing. This allows very slow flight without stalling, and facilitates 'riding the wind'. (It's also good for hovering, but that's another story.)

Waved Albatross Phoebastria irrorata. Española, Galápagos.
Albatrosses are also consummate soarers and utilise high aspect ratio wings.

However, everything in nature is about trade-offs and compromises, and most soaring birds do not have these very long slender wings.

Straw-necked Ibis Threskiornis spinicollis soaring, Grenfell, New South Wales.
(I love the way the two birds on the left are undertaking running repairs to their feathers.)

These ibis are soaring on very differently shaped wings from the ideal. The problem with the high aspect ratio wings is not with their undoubted efficiency in the air, but the problems they pose in getting there. Simply, they are so long that a normal takeoff is very difficult to achieve; they bang on the ground when being flapped! Large birds which possess them must either launch into the air from a high point (such as a cliff, which is what the Waved Albatross on Española were doing) or using wind energy to get into the air (which both albatrosses and frigatebirds also so).

The ibis use the compromise solution, known somewhat inelegantly but descriptively as 'soaring wings with slots'. These wings are broad and long, with deep slots between each primary feather to reduce air turbulence around the wing tips and promote easy soaring. While slightly less efficient than the albatross wing, they are shorter and enable relatively easy takeoff from the ground. 

Not only is soaring only effectively available to large birds (and formerly pterosaurs), because only they can have the large wing area to body weight ratio required, but the reverse is true too. As birds get closer to the cut-off maximum flying weight of around 15kg (the largest eagle, swan, condor, pelican, albatross and bustard are all about this size), soaring becomes the only realistic option, as sustained powered flight would be just too energy-intensive.

And with that, let's end by simply admiring some other magnificent soarers. 

Black-breasted Buzzard Hamirostra melanosternon, Uluru, central Australia.
Many soaring birds have black wingtips, because the melanin confers resistance to wear.

Andean Condor Vultur gryphus, Los Glaciares NP, Argentina.
One of the great soarers!

Galápagos Hawk Buteo galapagoensis, Santiago, Galápagos.

White-bellied Sea Eagle Haliaeetus leucogaster, Esperance, Western Australia.
A magnificent sight soaring along coastlines (and sometimes well inland) from India to southern Australia.

Little Eagle Hieraaetus morphnoides, Great Sandy Desert.

American Swallow-tailed Kite Elanoides forficatus, Ecuador.
One of the smaller soarers but an efficient one,
which in part uses the skill to glean prey from foliage.

Black-necked Stork Ephippiorhynchus asiaticus, Cobbold Station, north Queensland.

Australian Pelicans Pelecanus conspicillatus, Longreach Waterhole, Northern Territory.
Pelicans constantly criss-cross the continent by using rising thermals, especially over sand dunes.

Soaring, just another wonderful aspect of this wonderful world, and perhaps one we don't think about enough.

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Thoughts of Waza; part 2

This completes a posting I began here earlier in the week. I'd always meant to feature Waza National Park in the far north of Cameroon at some stage, following a visit in 2008, but I was prompted to do so now by the news of a murderous attack on a local bus by Boko Haram combatants crossing the nearby border from Nigeria on New Years Day. This follows earlier kidnappings by them of French tourists and Chinese engineers. These events have effectively closed the park and area to visitors for the imaginable future, cutting off a valuable source of income to locals. 

This is my tribute to those people and a magnificent park which deserves to be seen and supported. I may not see the day that adventurous nature lovers drive into it again, but I'm sure that the day will eventually come. 

Deep in the Sahel - that vast belt of arid woodland which blends into the Sahara to the north - Waza is dry, dusty and hot, but full of life. Accommodation is in traditional round huts on a rocky hill overlooking the park, by the village of Waza.

View of the accommodation from the plain, behind a herd of Korrigum Damaliscus korrigum (a threatened
species of limited distribution, formerly regarded as a subspecies of Topi D. lunatus).

The reverse view over the plain, from the restaurant balcony.

My cabin; basic but comfortable.

The habitat that I saw - and with 170,000 hectares to explore, there was much that we missed - was dominated by deciduous acacia woodland with a grassy understorey.

Typical habitat; below, the deciduous nature of some of the trees, and the grassy understorey,
are more evident.

 

There are 30 mammal species recorded for the park - including lion and elephant - but we only saw a few, not being there in the evening or night.

Korrigum herd; Waza is a stronghold of these antelope, which apparently number less than 2500 animals.
(The haze that renders murky many of these pictures is evident here. Dust or smoke, I can't say.)

Roan Antelope Hippotragus equinus, one of the largest antelopes at up to 300kg.

 

Patas Monkey Erythrocebus patas, a largely ground-dwelling monkey of the Sahel.

Warthog Phacochoerus africanus.

Even in the morning, before temperatures began to seriously rise, the waterholes were attracting many birds.

Chestnut-bellied Sandgrouse Pterocles exustus, above and below.
A highly mobile, arid-loving species found across central Africa and into southern Asia.
The relationships of sandgrouse are obscure; indeed they seem not to have any near relations.
I'd love to think that at least some of these beautiful birds were absorbing water in their dense breast
feathers to carry to chicks, a remarkable feature for which they are famous.

 

Helmeted Guineafowl Numida meleagris; found across sub-Saharan Africa, and a personal favourite.

Knob-billed Ducks Sarkidiornis melanotos have a remarkable distribution across Africa, southern Asia
and South America, but are never common and I was glad to see these.

A real thrill for me was a close-overhead flyover of a small flock of the magnificent Black Crowned Cranes.

Black Crowned Cranes Balearica pavonina in formation.
This beautiful bird is the national bird emblem of Uganda, and is unusual among
cranes in its preference for arid habitats. It is a threatened species.

Other bush birds were not so tied to the waterholes.

Vieillot's Barbet Lybius vieilloti, another Sahel special.
African barbets are regarded now as quite separate from their American namesakes.

Abyssinian Roller Coracias abyssinicus, one of the common birds of the Sahel,
but not one I could ever tire of.

I've felt that we've been a bit cheated with regard to starlings in Australia; we have only one native species, with a very small tropical range, and two widespread (and not especially colourful) aggressive exotics. Africa always reminds me of the alternatives!

Greater Blue-eared Glossy Starling Lamprotornis chalybaeus (what an immodest collection of
adjectives!) is much more widespread than the next starling.

Chestnut-bellied Starling Lamprotornis pulcher, yet another Sahel specialist, and an attractive one again.

And as I've suggested before, the day became hot (high 30s anyway), and the birds were dealing with it in their various ways.

African Swallow-tailed Kite Chelictinia riocourii, holding its wings out, hoping
for a scrap of breeze to cool it.

Gasping to allow evaporation from inside mouths and throats was popular.

Ethiopian Swallows Hirundo aethiopica.

White-throated Bee-eaters Merops albicollis breed in the Sahara itself, and come
this far south for winter.

African Silverbills Lonchura cantans hung about in the shade near the accommodation,
but still did their share of panting.

So, Waza, one of those places that for most of us we only hear of when it's too late. I was just lucky, and I'm so glad I was.

I'll go on thinking about it, and its fate, for a long time.

There'll be many such Waza sunsets through the thorn trees long after we've stopped
making a mess of things.

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