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I've been a Canberran since moving here from Adelaide on the first day of 1980. I now live in suburban Duffy with my partner Louise Maher, ABC 666 radio and on-line journalist. Among my early memories is following Sleepy Lizards (Shinglebacks) around the paddocks north of Adelaide, guarded by the faithful bull terrier. I have always been passionate about the natural world, trying to understand how it works, how the nature of Australia came to be, and sharing those understandings. My especial passions are birds, orchids and mammals. I am now a full-time naturalist, running bush tours, writing books etc, doing consultancies, presenting a regular radio slot on local ABC, chairing a government environment advisory committee and running adult education classes. I was awarded the Australian Plants Society Award in 2001 and the Australian Natural History Medallion in 2006, both for services to education and conservation. As part of my fascination with our Gondwanan origins I've been running tours to South America for the past few years.

Monday, 25 August 2014

Magnificent Murchison (the Ugandan one). Part 1.

The bracketed clarification in the title refers to the lovely and dramatic Murchison Gorge area of Western Australia, which I introduced in these pages last year. Now it's the turn of the wonderful Murchison Falls National Park in Uganda, a place I'd been greatly looking forward to visiting, not least because it would be my first experience of the mighty Nile River. I travelled with the excellent Rockjumper Birding Tours of South Africa. The park (including a couple of adjoining reserves) protects some 5000 square kilometres of country, including rainforest, vast stretches of woodland, the northern section of Lake Albert (across which is the Democratic Republic of the Congo) and some of the Nile.

It exists because of the Tsetse Fly Glossina spp., vicious little grey-and-black-striped, bullet-shaped flies with a wicked bite which is not at all deflected by clothing. More significantly it also carries trypanosome protozoans which make the area uninhabitable to European stock. (Another trypanosome also causes Sleeping Sickness.)
Murchison Falls National Park - location indicated by end of red arrow. The Nile flows in from the east,
enters the northern end of Lake Albert and flows north again without spending much time in the lake.
The falls themselves are on the river east of the lake.
The eponymous falls are the most famous part of the park, and understandably so, but there is no doubt the park would be worth visiting even without them. However, there's good reason to start with them. The river is squeezed through gorges that are not especially high or long, but with a force purported to be the greatest of any such natural system in the world.
The Nile above the falls.

The falls themselves; the pressure and roar are extraordinary.

Gorge below the falls.

The Nile opens out again below the falls.
The handsome Rock Pratincoles Glareola nuchalis spend much of their time on the rock platforms,
among the spray, from where they forage for insects on the wing. When the river rises and the platforms
become submerged, they move somewhere with lower water levels.
North - downstream - of Lake Albert, the Nile opens out to well over 100 metres wide, though narrows to about half that fairly soon. Hippos, crocodiles, antelope, buffalo and numerous birds adorn the banks. Papyrus banks fringe the river.
The Nile downstream of Lake Albert; the foam on the surface is probably still
courtesy of the enormous churning in the falls.

Papyrus beds along the banks of the Nile. Papyrus is a sedge, Cyperus papyrus, which grows to five metres tall and
forms dense riverside herbaceous 'forests' throughout much of Africa. From papyrus (a Greek word of
unknown origin) comes our word 'paper' because of the use of the pith of the plant to make a parchment,
starting with the ancient Egyptians.
Another Greek word for it, bublos, gives us book-referring words such as bibliography and bibliophile.

Hippopotamus on the banks of the Nile.
The extraordinary Shoebill Balaeniceps rex, also seen on the banks of the Nile, a highlight of the visit.
For more on this wonderful and elusive bird, see here.
Vehicles cross the river at Paraa on a ferry which, though effective enough, can best be described as basic. It comprises a floating mesh platform powered by a robust but very smoky motor. Unusually for Africa it runs strictly to schedule; it only runs four times a day and even arriving five minutes late can lead you to be stranded. (However if you are on time and the ferry is full, it will come back for you!)
Paraa vehicle ferry across the Nile, Murchison Falls NP.
This African Pied Wagtail Motacilla aguimp lives by the ferry, even riding on it, to take advantage
insect life disturbed by all the activity.
Warthogs are more robust and less fastidious exploiters of the accumulation of visitors
at the ferry crossing, shamelessly going through the garbage.
There is a range of accommodation in the park; we stayed at Sambiya River Lodge (which is not actually on the river...), in very pleasant self-contained round thatched cabins.
Sambiya River Lodge cabins, above and below.


Lovely wooden beams and spider web motif, Sambiya River Lodge dining room.

Very leafy and grassy grounds, Sambiya River Lodge.
(Though one is cautioned to be on the lookout for buffaloes...)
The entry to the park from Masindi (and ultimately Kampala) is inauspicious and tucked away in an unsignposted maze of rough tracks - I suspect that many visitors fly in.
Entrance to Murchison Falls NP; I would fear that the elephant tusks were real,
except that I don't imagine they'd still be there if so!
This entrance takes us into the Kainyo Pabidi rainforest - part of the extensive Budongo Forest - where there is a basic lodge.
Kainyo Pabidi rainforest, Murchison Falls NP.
We spend a lot of time here looking for the surprisingly drab and skulking Pavel's Illadopsis Illadopsis puveli;
I say surprising because of the assiduousness with which it is sought, but the reason is that in Budongo
is its only occurrence in East Africa.
Most of the park however is dominated by vast open expanses of woodland; big areas of rolling hills are almost treeless.
Acacia-dominated savanna woodland.

Grassland with Oribi Ourebia ourebi.

Elephants and palm trees in the Murchison Falls NP landscape.
And of course we've hardly looked at the rich animal life yet, but I think that had best be left until next time - there's a lot of it!

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Tuesday, 19 August 2014

There Be Dragons!

 There certainly be! (OK, there certainly are...). Some 350 species of them in fact, found across Africa (and slightly into Europe), Asia and Australia. This family, Agamidae, is a 'sister' family to the iguana family (Iguanidae) of the Neotropics and some of the Pacific and, strangely, Madagascar. It's a funny thing, but this rather odd distribution of the iguanas neatly fits into the gaps left by the dragons; where dragons are, iguanas aren't, and vice versa.
Bearded Dragon Pogona barbata, Eyre Peninsula, South Australia.
This smallish dragon (ie a young one - adults can be over 50cm long) shows the
characters which immediately distinguish the family. They have strong clawed legs on which
they stand clear of the ground, and have rough, even spiny, scales which don't overlap each other.
The tail is long and whiplike, and doesn't regrow if broken (unlike a skink's for instance).
This Central Bearded Dragon Pogona vitticeps, Windorah, South-west Queensland,
was too cold to run away - the usual defence of dragons - allowing a good view of its spiky scales.

Diporhiphora magna (no common name that I know of), Litchfield NP, south-west of Darwin.
The long whippy dragon tail is very pronounced in this species.
Their family is an old one - indeed, although we regard them as lizards, they (and the iguanas) are less closely related to other lizards than snakes are. One character not visible in the pictures above is the teeth; dragons have acrodont teeth, which means they don't have sockets, but are fused at the base to the surface of the jawbone. It's a common feature in fish and frogs, and isn't a very secure system, as teeth break easily. This doesn't mean they don't work perfectly well, and incautious handling of a wild Beardie has left me quite effectively lacerated on more than one occasion!

Nearly all dragons (and all Australian ones) lay soft-shelled eggs. She buries them - there may be as many as 30 - and leaves the young to burrow out again.
Southern Angle-headed Dragon Hypsilurus spinipes laying eggs in a rainforest track, Lamington NP, Queensland.
I've only been lucky enough to see this event once, and a long time ago, hence the indifferent picture
- a scan of a faded old slide.
As mentioned previously, most dragons can run at astonishing speeds, even rising onto their hind legs to do so. One group of Australian dragons is known as 'bicycle lizards' for this behaviour!
Crested Dragon or Bicycle Lizard Ctenophorus cristatus, west of Norseman, Western Australia.
Note the very long powerful hindlegs for running upright.
There is the hint of the bright brick red on this dragon which will characterise him as breeding begins. This too is typical of many dragons. 
Painted Dragon Ctenophorus pictus, Cape Bauer, South Australia.
The handsome blue flush will spread to his face when breeding starts.
Gippsland (Eastern) Water Dragon Intellagama (formerly Physignathus) lesueurii, National Botanic Gardens, Canberra.
There is a healthy population of these beauties adorning the gardens; only old males attain these striking colours.
Like many dragons these lizards climb well, but they also swim powerfully, dropping from a branch into
the water if disturbed. (Mind you, this particular population doesn't get disturbed easily - they will come to outside
tables at the restaurants hoping for dropped scraps!)
 
Rainbow Agama Agama agama, Douala, Cameroon. Only the males attain these superb colours, and only when breeding. At other times they are dull brown, as are females all year round. There is an apparently healthy population
of them on the footpaths and open spaces, including petrol stations, in this huge crowded city.
Blue-headed Tree Agama Acanthocerus atricollis, Queen Elizabeth National Park, Uganda.
Breeding male above, and female (or possibly non-breeding male) below.

Agamas can be very sociable, and interactions are common.
Agamas in open-air restaurant, Waza NP, northern Cameroon.
Gilbert's Dragon or Ta Ta Lizard Amphibolurus gilberti, Bladensburg NP, Queensland.
The curious alternative common name comes from its habit of 'waving' to rivals, as this one is doing,
to indicate that it is in its territory and aware of neighbours.
Like the Ta Ta Lizard, many dragons perch high to watch for both danger and prey - all are carnivores.
Bearded Dragon, Temora, New South Wales.
They can adjust the melanin-bearing cells in the skin to turn almost black to absorb extra sunshine.

Ring-tailed Dragon Ctenophorus caudicinctus, East MacDonnell Ranges, Northern Territory.

Jacky Lizard Amphobolurus muricatus, Pretty Beach, New South Wales,
in typical position.

Gilbert's Dragon Lophognathus gilberti, Darwin.

Dwarf Bearded Dragon Pogona minor, Lesueur NP, Western Australia.

Tommy Roundhead Diporiphora australis, Mareeba, Queenland, on termite mound.
It is often said that Australia's great lizard diversity is founded on the abundance of termites in arid lands.
And finally, just a couple more arid land dragons.
Spotted Military Dragon Ctenophorus maculatus, Lake Logue NR, Western Australia.

Lined Earless Dragon Tympanocryptis lineata, Bladensburg NP, Queensland.
These heat-lovers can be remarkably well-camouflaged against coloured desert stones.

Thorny Devil Moloch horridus, Desert Park, Alice Springs.
Surely one of the most extraordinary of all dragons; despite appearances, a slow,
harmless ant specialist. More information about this fascinating animal here.
Love your dragons - I certainly do!

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Thursday, 14 August 2014

The Pollination Story, Part 5; beyond birds - other vertebrate helpers

This is part of an ongoing series on pollination, which I truly believe is one of the world's great stories. Last time we got as far as looking at the role of birds, dream customers for a plant wanting pollen to be taken to distant flowers of the same species by highly mobile animals able to remember subtle cues to make sure they deliver to the right species.

It's only surprisingly recently that the role of other vertebrates, notably mammals, has been likewise recognised. Back in the 1970s research began into the possible role of mammals as pollinators in both South Africa and Australia, but while the South Africans showed that a range of small mammals, notably rodents, small primates and elephant shrews, were effective pollinators, the Australian research petered out for a while.
Cape Rock Elephant-shrew (or Sengi) Elephantulus edwardii with Cytinus visseri.Photo courtesy BBC.
More recently however, long-term studies by the University of Wollongong on the south coast of New South Wales dramatically changed our perception of the importance of mammals as pollinators here. They put traps by flowers of Waratahs Teleopea speciosissima and various Banksia species, all large showy-flowering members of the family Proteaceae, hitherto assumed to be solely bird pollinated.
Sydney Waratah (above) and Heath-leafed Banksia B. ericifolia;two of the seven flower species studied in coastal southern New South Wales.
Mammals were trapped by all seven species, and all of them were carrying pollen in their fur and their droppings. The most abundant species was the supposedly carnivorous Brown Antechinus A. stuartii, followed by Sugar Gliders Petaurus breviceps, Eastern Pygmy Possums Cercartetus nanus and Bush Rats Rattus fuscipes.
Bush Rat, a perhaps unexpected pollinator.

Sugar Gliders, probably less of a surprise.
A further surprise was the observation that they were feeding thoroughly and non-destructively; these were very effective and obviously non-incidental pollinators. The commonest pollinating honeyeater in the area was the Eastern Spinebill Acanthorhynchus tenuirostris - the one most of us would probably have nominated as the most important pollinator operating there. In fact on average the spinebills were carrying around 40 pollen grains each, while the antechinuses were bearing over 400 grains and the Sugar Gliders more than 2000! The gliders were carrying pollen up to 60 metres from the flower, while antechinuses were travelling about half that. (Determined, incidentally, by attaching little spools of thread to their backs and following them the next day.)

The real clincher however came with the application of exclusion experiments - covering flowers with bags by day or night, since all the mammal pollinators were nocturnal, and all the birds (and nearly all the insects) were diurnal. Mammal-only pollinated flowers had three times the seed set of flowers only visited by day.

We now now know of at least 25 Australian marsupials and two rodents which visit flowers; the two rats, six little possums and the strange Western Australian Dibbler Parantechinus apicalis, a carnivore, do so regularly. Of these the best-known is probably the remarkable Honey Possum, or Noolbenger, Tarsipes rostratus, the only mammal in the world known to be entirely dependent on nectar and pollen.
Honey Possums on Eucalyptus macrocarpa.
(Photo from web.)
In general mammal-pollinated flowers will have characteristics including the following. They are likely to have tight inflorescences with strong stems and a high nectar flow - all these characteristics are shared with bird-pollinated flowers. Other characters however, to deter birds, include nocturnal flowering, dull colours, flowers close to the ground or hidden inside foliage. Some are reported to have musky 'mouse-like' scents.

Creeping Banksia Banksia repens, Stirling Ranges NP, Western Australia.
One of several WA mammal-specialising banksias whose dull-coloured flowers grow from
stems on or just under the ground.
In addition to South Africa, studies have also been carried out in Madasgascar and South and Central America, with equivalent results. In Madagascar the key mammal pollinators unsurprisingly were lemurs (both large ones and mouse lemurs); in the Neotropics small monkeys were significant, along with marsupials, rodents and climbing carnivores.
Golden-mantled Tamarin Saguinus tripartitus, Napo Lodge, Yasuní NP, Ecuador.
The tamarins are particularly significant Neotropical pollinators.
It is highly likely that many mammal pollinators in Asian forests remain to be identified, but already there are over 60 pollinating non-flying mammal species known - and this is without considering the most significant furry pollen-transferers.
Grey-headed Fruit Bats Pteropus poliocephalus, Canberra (above)
and Bellingen, northern New South Wales (below).
Scores of bat species feed on blossoms, as well as fruit, and carry the pollen (and seeds)
for tens of kilometres.

In the tropics too, many species of micro-chiropterans (the essentially insectivorous echo-locating small bats) have secondarily also adopted flower-feeding habits, and have become highly specialised pollinators. A lot more work seems to have been done in the Neotropics than elsewhere, so doubtless we have much to learn. Probably thousands of tropical plants rely heavily or even solely on bat pollinators. Many have strong complex scents, including some described as 'plasticky'. Unlike the big fruit bats which visit flowers by climbing nimbly among branches, the little bats simply hover briefly in front of flower after flower. 

One bat-flower story however has grabbed my attention since I first read about it a decade ago. It concerns a tiny Central American blossom bat called Glossophaga commissarisi and a night-flowering vine called Mucuna holtonii.The vine hangs its flowers in clearings and attracts distant bats with a strong sourish-garlicky smell. When the bat gets closer however the bat starts to 'ping', as it would if navigating in tight spaces or hunting insects. In this case though it is examining the flowers. When the flower is ready for pollination, when it also provides nectar, it erects a strange concave petal which perfectly reflects the bat's sonar back to it - the bat can hear that the flower is worth visiting! It briefly grasps the front of the flower and inserts its head, where its long tongue probes the nectar. This act however also sets off a trigger, which causes anthers to emerge and dust the bat's back with pollen... Amazed? I am!

Mucuna holtonii flowers.
Courtesy of La Selva Florula Digital.
There are some amazing pictures on the web of the bat actually pollinating the flower,
but understandably the owners are pretty protective of them, so I can't show you here.
They're worth looking for though!

More recent ingenious experiments with artificial bat heads, emitting and collecting ultrasonic sound directed at a range of tropical flowers, have indicated that each flower tested could at least theoretically be distinguished by a flying bat.

But astonishingly it's not just birds and mammals among vertebrates which pollinate - reptiles, notably lizards, are involved too! This is apparently especially true on islands, where presumably the plants have less choice. In New Zealand and Mauritius geckoes are known pollinators, visiting the flowers for energy in the form of nectar. 
Gecko Phelsuma cepediana on Roussea simplex, Mauritius.
(The plant incidentally is now threatened following the introduction of exotic ants, which
feed on the flowers and repel the geckos.)
Photo courtesy National Geographic.
I'll end though with another Australian story, which I also find almost incredible, of a lizard which doesn't actually pollinate but is essential for the event to take place. On Mount Wellington above Hobart in Tasmania life is tough, and the Honey Bush Richea scoparia protects its reproductive parts in a capsule of fused petals.
Typical Mount Wellington habitat in the foreground, above Hobart (above).
Richea scoparia below.


So how do pollinating insects enter? The answer is - a lizard!

Snow Skink Niveoscincus microlepidus.Courtesy Australian Reptile Online Database.
Snow Skinks are common insect hunters on Mount Wellington (not when I was there last - too cold for any sensible animal to be above ground level!). However in summer they switch almost exclusively to Honey Bush nectar, which they obtain by ripping open the capsules, allowing insects to access anthers and styles. The flowers must mature at the mildest time of the year (on Mt Wellington that is relative!), and advertise the fact to the lizards by turning brown. How I love nature's remarkable stories.

More on pollination in coming weeks; I do hope you're as captivated by the nuances of the story as I am.

MEANTIME, BACK ON TUESDAY