About Me

My photo

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. For much of my life I have been 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. Recently I have eased back somewhat, but am still writing, teaching, doing some radio work and running overseas tours - as part of my fascination with our Gondwanan origins I've been running tours to South America for the past decade. 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.

Thursday, 23 March 2017

Bunya Mountains National Park; splendid isolation

Actually the Bunyas, in the hinterland of south-east Queensland, aren't really so isolated in terms of visiting them, but ecologically they represent a remnant of ancient Australia, rainforests left behind when the plains around them dried out, surviving in the cooler moister shelter of the ranges.
Subtropical rainforest creek line on one of the Bunya Mountains walking tracks.
The surrounding plains have been almost entirely cleared for agriculture but they were until relatively recently covered in dry Brigalow (Acacia harpophylla) forests and vine forest, or bottle tree scrub - as indeed the base of the Bunya Range still is. 
Bottle tree scrub, with Narow-leaved Bottletree Brachychiton rupestris.
The range is based on layers of basalt from volcanic eruptions, the most recent of which occurred 22 million years ago. While isolated it is functionally part of the Great Dividing Range, in that rain falling on the eastern slopes flows to the Pacific while water from the south-western slopes runs into the Condamine, and ultimately via the Balonne, Darling and Murray into the sea in South Australia.
Location of Bunya Mountains, 150km inland from the Sunshine Coast in south-east Queensland.
Famously the area was of enormous significance to indigenous people for the sporadic huge bounty supplied irregularly by the synchronised Bunya Pine seed production. It was a time when many peoples gathered and it was immensely important socially as well as economically; it's a story that's readily available and you can read accounts of it from people much more qualified than I am to tell it. Needless to say, tragically, those traditions were disrupted and then destroyed, not least due to the logging of the valuable timber resources of the range's forests. The last major gathering took place late in the 19th century; it seems to me that this underlines its importance, as much of the culture would already have been lost by then.

Europeans have been visiting the mountains for recreation since the 1860s, and in the 1880s a 12,000 hectare timber reserve was declared in an attempt to at least moderate the harvesting. In 1908 a 9,000 hectare national park was declared - this was the first major national park in Queensland (coming just months after the tiny Witch's Falls, now a section of the Tamborine National Park). Nonetheless logging continued for another decade or so! The park has since doubled in size to nearly 20,000 hectares and while logging has ceased, there are still conflicts from the proximity of residences and businesses high in the range on the park boundary - as these signs indicate.
These signs face each other across a narrow road - obviously enough,
the sign above is in the national park.
 

The subtropical rainforest, dominated in part by the mighty Bunya Pines Araucaria bidwillii, dominates the upper parts of the range (which rises to 1100 metres above sea level). The pines belong to one of the old Gondwanan conifer families, Araucariaceae; the species was named for John Bidwill, acting NSW Government Botanist and Director of the Botanic Gardens and later Commissioner of Crown Lands and chair of the Bench of Magistrates for the Wide Bay region of Queensland (then still part of New South Wales). He passed the material on to Sir William Hooker of Kew, who described the tree. 

Ancient emergent Bunya Pines; the dome-shaped canopy is diagnostic.
They are restricted to a few areas of south-east Queensland, plus a couple of small
relic populations far to the north in the tropics.


Bunya trunk; it has been claimed that the notches were cut by indigenous cone harvesters,
but it seems that this must remain just a good story. Inter alia, I'm sure those scars would have grown over
well before now; perhaps they represent former limbs.


The massive cone of the Bunya Pine (and a much younger bloke in a world where blogging
hadn't been dreamt of!). It is not wise to linger under the pines when cones are ripe!

Alongside the Bunyas grow the closely related Hoop Pines (though in theory they favour lower drier elevations). This species, A. cunninghamii (for the illustrious explorer-botanist Allan Cunningham), is much more widely distributed, found from northern New South Wales to New Guinea; it is also grown in timber plantations.
The very distinctive erectly ragged crown of Hoop Pines.

Clearly these Hoop Pines are growing in rainforest, complete with massive Bird's Nest Fern epiphytes.

Hoop Pine trunk, with the 'hoops' for which it was named.
Another significant difference from Bunya Pines is in the cones, which are tiny.
Like other subtropical forests this is a simpler forest than the tropical forests further north, but shares characteristics such as lianas, buttresses, epiphytes, strangler figs and many ferns, and is a lovely place to walk through; there is an excellent array of walks to choose from.
Bunya Pine-dominated forest.

An opening in the forest, with tree ferns and rapidly growing Giant Stinging Trees,
which specialise in colonising such clearings.

A tangle of fallen lianas.

An old, knotted liana.

A bank of ferns and cordylines.
Broad-leaved Palm Lily Cordyline petiolaris, above and below.
In the new lily taxonomy it is placed in the family Asparagaceae; it is found
throughout the near-coastal sub-tropics of Australia.
 


Leaf of Giant Stinging Tree Dendrocnide excelsa - it is literally a tree-sized stinging nettle, in the
family Urticaceae. You can see the stinging hairs around the chewed sections. The leaves always seem
to be nibbled, so the defences obviously only work against larger animals - but they certainly do work on me!
Buttresses on Churnwood Citronella moorei, family Cardiopteridaceae.
The Citronella was applied to a Chilean species; moorei for Charles Moore, NSW government botanist.
Strangler Fig Ficus watkinsiana; for more on stranglers, see here, but essentially they kill their host not
by strangulation but by shading them to death.
This one has a curious distribution in two isolated populations, one in northern New South Wales and south-east
Queensland, and one in tropical Queensland..

Cyathea cooperi, a tree fern, found along the eastern coast.
Unfortunately it has become an invasive weed in Hawaii and has invaded areas of southern Australia.
 Waterfalls feature on some of the walks.
Festoon Falls.

Paradise Falls; maybe a bit of hyperbole, but they are very pleasant!
Another favourite walk of mine in the Bunyas is the one up Mount Kiangarow, the highest point of the range (the walk actually starts high up and ascends very gradually). It starts in rainforest....


....but rapidly emerges into dry open forest, where a feature is the wealth of huge ancient grass trees, Xanthorrhoea glauca. They are certainly the largest of this species that I know, and only on Kangaroo Island have I seen others of similar size.
This magnificent specimen is at Burton's Well campground, at the start of the walk.

Avenue of grass trees along the track to the summit.


View from Mount Kiangarow, looking out over the park in the foreground and
the heavily cleared rich agricultural land of the Darling Downs beyond.
Another habitat which is of great interest in the Bunyas is the system of hilltop grasslands known as the balds. Their origin is unclear, though the presence of species restricted to them, including the locally endemic grass Bothriochloa bunyensis, strongly suggests they are natural. It is thought they are relics of the last glaciation; in recent times there has been considerable invasion of them by forest, which may be a product of global warming. Attempts are being made to counter this with use of fire.
Two views of some of the balds; there are well over a hundred of them along the ridges of the range.

Wildlife is rich, though I've not got a lot of photos - inter alia photography in rainforests is for those with better skills and equipment than I!
Carpet Python Morelia spilota, objecting at being asked not to lie on the road.
This is a scan of a slightly faded old slide from an early visit.
Red-necked Wallabies Macropus rufogriseus; along with some other animals they hang around
the visitor areas, but I prefer to show you slightly wilder ones where possible!
Brush Turkey Alectura lathami, another which has no problems making a living from visitors.
A mound-builder, which incubates its eggs in a huge pile of managed compost.
Male Superb Fairy-wren Malurus superbus. One of the most abundant and familiar birds in south-eastern Australia, but one more photo is never quite enough...
Female Paradise Riflebird Ptiloris paradiseus, one of three closely-related birds of paradise from
eastern Australian rainforests. An awful photo (again a scan of an old slide) but a special bird.
Juvenile (and wet!) Green Catbird Ailuroedus crassirostris; the two Australian catbirds are
relatively primitive bowerbirds which don't build display bowers, and which yowl loudly like cats
or crying babies, quite disconcertingly if you don't know them!

Topknot Pigeons Lopholaimus antarcticus, preening high in a Bunya Pine.
This big strange-looking fruit pigeon has no close relatives.
White-browed Scrubwren Sericornis frontalis. This active little group of birds had me fooled for a while -
I took them to be Yellow-throated Scrubwrens, but they are particularly yellow examples of the Queensland
race laevigaster. (If you're still wondering, the pale iris and distinctive white 'whiskers' are giveaways.)
 
And lastly this intriguing little character, twirling apparently contentedly at the end of a silken thread.
If you've not been to the Bunyas yet - or even if it's just been too long since you were there - take a detour when next you're in the vicinity, or even make a special trip! You won't be sorry.

PLEASE REMEMBER THAT I ALWAYS VALUE YOUR COMMENTS!
THEY CAN BE ANONYMOUS (THOUGH OF COURSE I'D PREFER TO BE
ABLE TO THANK YOU BY NAME) AND YOU DON'T NEED A GOOGLE OR ANY OTHER ACCOUNT.
BACK ON THURSDAY
 (And remember that you can get a reminder when the next post appears by putting your email address in the Follow by Email box in the top right of this screen.)


Thursday, 16 March 2017

Ratites; the ancients of the bird world. #2 The case of the flying moas

In introducing the wonderful and venerable ratites last time I made mention of another group of relatively little-known birds, the tinamous, long described as a 'sister group' of the ratites. There are 47 species of them in South, Central and North America, as far north as about central Mexico. Like the ratites they are Palaeognaths, forming with them an entirely different group of  birds, the 'ancient palates'. They fly poorly but can still do so and, unlike the ratites, thus retain the keel on the breast for anchoring the mighty flight muscles. They also differ from the ratites in having powder down feathers - amazing feathers which are never moulted, but which crumble at the tip to provide a permanent supply of conditioning powder (sort of like home-made talc) for cleaning and generally improving the feathers. For these reasons it has always been assumed that they separated from the ratites early in the piece, but travelled with the rheas when South America broke free of Gondwana. This means too that they couldn't actually be ratites, because that would imply that they had a common flightless ancestor with the rheas and regained flight in South America - such a reversal of all the acquired adaptations to a flightless lifestyle is universally regarded as an evolutionary impossibility.

Tinamous are notoriously shy, and to date I've only seen three species - all rainforest birds - two of them at one sitting, courtesy of the wonderful Aguas Verdes initiative in northern Peru, where forest birds are lured to a hide by offerings of corn. As a result the forest has been spared from conversion to coffee, and other landowners are taking interest; more on this story here. 
Cinereous Tinamou Crypturellus cinereus, Aguas Verdes, lower eastern Andes slopes, northern Peru.
This shows typical tinamou characteristics - strong running legs, and virtual lack of a tail,
which is associated with their reluctance to fly, and general lack of competence at it.
This is a medium-sized tinamou, weighing about half a kilogram.
The Little Tinamou Crypturellus soui is indeed one of the smaller tinamous,
weighing only 200-250 grams.
Tinamous, as I mentioned, are very hard to see normally, and this cryptic behaviour has saved them to some extent from dramatic losses suffered by other largish edible birds in their range. Nonetheless hunting pressures can be severe, along with steady habitat loss.
Great Tinamou Tinamus major at roost, Napo Lodge, Ecuadorian Amazonia.
This is a species that is facing problems, having been recently listed as Near Threatened.
It is a big tinamou, weighing well over a kilogram.
OK, you've been very patient - if indeed you're still reading! - while I go on about a group of birds that aren't really ratites. However, that's only what we used to think... I've been at some pains to introduce them because new understandings about them have changed pretty much everything we now think about ratites too. The nice neat story about ratites representing the archetypal Gondwanan story - an ancient group which inhabited all the southern lands before they parted ways, and drifted with the new continents to their new positions, was very appealing and was one I've told, in all good faith, many times over the years.

There have been some mutterings over the years along the lines of "OK, they're old, but not quite that old!". The mutterers had some good points - for instance Africa broke free of Gondwana by at least 110 million years ago. Madagascar was isolated by 88 million years ago – but from India rather than Africa! But still, how else could we explain what we see? Then in 2010 a paper was published by a group of Australian and New Zealand scientists which turned this particular comfortable understanding of the world inside out. They had available to them techniques denied to earlier researchers, including the ability to do a complete mitochondrial DNA analysis (mitochondria contain far less DNA than do cell nuclei, and this DNA seems to evolve more quickly than does that of the nucleus so tells good stories) and to look at such material from fossils.

The technique has rapidly become widely used to study a range of animal groups, comparing species to determine when their Most Recent Common Ancestor walked the earth ('MRCA' appears all over the place now). Phillips et al shocked us all by announcing that far from being associates of the ratites, tinamous are slap bang in the middle of them - they are ratites for any practical purposes. One existing hint (isn't hindsight wonderful?!) might have been that tinamous, like most other ratites, breed most unconventionally - a male waits to be visited by groups of roaming females who mate with him and lay their eggs into his nest, then move on and find another obliging dad for their eggs. (There are a few tinamou variations, but this is the norm.) It is generally regarded as a very efficient way of rapidly increasing populations.
Darwin's Rhea father and chicks - who between them have many mums - Torres del Paine NP, Chilean Patagonia.
From the conventional viewpoint however it gets worse - the closest relative of tinamous are not the obvious rheas, but the New Zealand moas! Moreover the same study showed that Ostriches and the recently extinct Madagascan elephant birds are not each other's closest relations, as logic would insist, but the elephant birds and kiwis are closer to each other than they are to anyone else... Ostriches are way out on the ratite fringes - and may have even arisen in Eurasia, arriving in Africa only some 23 million years ago.

The only way to make any kind of sense out of all this is to accept the seemingly preposterous idea that the ancestral ratites flew to their current continents, then all (except for the tinamous) subsequently lost the power of flight. Kiwis and emus/cassowaries parted ways only 60 million years ago - but by then New Zealand had been isolated for 20 million years. Moas and tinamous separated at about the same time.

It's a difficult concept to absorb. I've always been a firm believer in the parsimony principle – ie that the simplest evidence-based explanation is always likely to be the correct one. The more evolutionary steps that are required to explain something, the less likely it is that it happened that way. But once we accept, however reluctantly, all this explosive material, how on earth are we - or at least the researchers - supposed to explain such a bizarrely unlikely set of circumstances? What could possibly have happened right across the Southern Hemisphere to have triggered a series of wildly unlikely parallel events at about the same time?

Well, of course something did. Around 65 million years ago, already a time of colossal volcanic activity, a massive meteorite, an asteroid some 10km across, smashed into what is now the Yucat√°n Peninsula of Mexico, hurling vast quantities of dust and smoke into the atmosphere and dropping temperatures cataclysmically. Sulphates hurled into the air formed nucleation sites for brutal acid rain storms. Once the dust particles settled the huge quantities of carbon dioxide released raised worldwide temperatures for centuries. By the time things had started to settle down again, three quarters of all plant and animal species on earth had vanished, including all the dinosaurs (other than some of the birds of course). 
Southern Cassowaries, Etty Bay, North Queensland.
Their small flying ancestors survived the great meteorite strike.
It was an empty landscape, full of menace and opportunities. Among the now-empty niches was that formerly occupied by the birds' immediate ancestors, the erect running dromaeosours. We know that birds, especially on islands, are prone to give up the enormously energy-demanding flight habit when there is no longer a pressing need for it. So, it is not at all hard to conceive that members of a particular group of bird survivors, with the genes of the dromaeosaurs still within them, should have responded to landscapes suddenly largely devoid of predators and full of options, by giving up flight that had carried their ancestors across the oceans. Later they also grew larger in response to such predators that did eventually arise.
Darwin's Rhea chicks, Patagonia.
Their ancestors flew to South America, arriving quite separately from the (apparently later) tinamous.
An unlikely story, but the only one that fits the facts - and the job of science, and indeed of common sense, is to find theories to fit the facts, rather than deny the facts to fit a theory.

And doesn't it make a good story?!

PLEASE REMEMBER THAT I ALWAYS VALUE YOUR COMMENTS!
THEY CAN BE ANONYMOUS (THOUGH OF COURSE I'D PREFER TO BE
ABLE TO THANK YOU BY NAME) AND YOU DON'T NEED A GOOGLE OR ANY OTHER ACCOUNT.

BACK ON THURSDAY
 (And remember that you can get a reminder when the next post appears by putting your email address in the Follow by Email box in the top right of this screen.)

Thursday, 9 March 2017

Ratites; the ancients of the bird world. #1 Who are they?

Across the southern lands are (and in some cases were) scattered a series of mostly giant, flightless birds, whose significance we often overlook. We call them the ratites, from Latin for a raft, a reference to the flat breastbone - if you no longer fly, you no longer need either the great flight muscles (some 15% of your bodyweight) or the keel on your breastbone to anchor them. 
Emus Dromaius novaehollandiae near Esperance, Western Australia.
Their significance in the world of birds is their undisputed role as The Elders. The most fundamental subdivision of the world of birds is not, as one might expect, into Passerines and Non-passerines, but into the Palaeognaths (the 'ancient palates') and the Neognaths ('new palates'). The details of the palates needn't concern us here, but the elemental subdivision thus created certainly does, because the Palaeognaths comprise just the ratites and their associated 'sister group' the South American tinamous (but more on them later). It's just them versus every other living bird!

Since we've started this introduction to them in Australia, we might as well continue here. When Europeans arrived here there were probably three species of emus. The small emus on Kangaroo Island (off the coast of South Australia) and King Island (in Bass Strait between the mainland and Tasmania) are generally regarded as separate species (D. baudinianus and D. ater respectively), but the evidence is tragically limited, with only one and three skins respectively surviving. Some authorities take a more cautious approach and regard them as sub-species. There were also Tasmanian Emus which were almost certainly the same species as the mainland birds; they were gone by the 1860s, while the other two were exterminated horrifically soon after the arrival of Europeans in the early decades of the century.
Kangaroo Island Emus, by French self-taught natural history artist Charles-Alexandre Lesueur, who
sailed with the Baudin expedition of 1800-1803. While visiting Kangaroo Island they captured two
unfortunate emus and took them back to France.
On the mainland they're still doing well, though they retreat from settlement and are now very rare in the south-eastern highlands. I'll talk more about Emus than the others, both because I know them best, and because much of the information about them can be used to compare the others.

Emus on the Hay Plain, south-western New South Wales.
They are found across all of inland Australia, where they are nomadic, following the rains and feeding on seeds or fruits or caterpillars or grasshoppers as conditions dictate. This nomadism and their disdain for fences has led to many of their problems with European settlement. In Western Australia the 'Great Emu War' of 1932 was fought between migrating mobs of over 20,000 emus, and the Australian army with machine guns and grenades, called in by the WA government. Jock Marshall in his pioneering conservation work The Great Extermination (published in 1966, just before he died, far too young) reports "History does not record the name of the CO emus, but he must have been a good chap". It seems that perhaps only a dozen emus were killed, and the government had to withdraw the military to save them from further embarrassment.

Like most ratites, Emus are polyandrous, though they start off the breeding cycle as a pair in mid-summer, and dally for about five months. In late May and June she lays up to 20 large dark green eggs in a scrape on the ground, totalling up to 15kg. Not surprisingly, she reckons by now that enough is enough, and she plays no further part in the process, though if she’s still feeling frisky she can go off and do it all again with someone else! Each time she leaves the father in sole charge. He broods for eight weeks, and during the whole time he lives off his body reserves without eating, drinking or defecating, rousing only to turn the eggs several times daily. In this part of the world eggs were apparently laid in about July, which meant that the male was incubating in the snow.

Emu eggs, north-western New South Wales.
In South America rheas are even more Bohemian (from a very anthropomorphic perspective!). The texts tell us that “males are simultaneously polygynous, females are serially polyandrous”, which means that males become territorial, while females form small mobile groups which roam around seeking collective dalliance with likely-liking blokes. He mates with the group of females who all lay eggs in his nest, then go off to look for another bloke to do it all again.  

Darwin's Rhea Rhea pennata and chicks, Torres del Paine NP, Chilean Patagonia.
Kiwis on the other hand are always monogamous, while ostriches can be monogamous in harsh desert situations, though their usual approach is much more complex. A dominant male and female share brooding duties, while in the same territories subordinate females mate with multiple subordinate males and leave them to get on with, as with the emus. At the same time roaming males pass through and mate with the females, but it's not clear who ends up holding the baby in that situation.

The striped Emu chicks can walk within hours, and run and swim within a week. As they get older, they are distinguished from older birds by a dark neck and head. Dad cares for them for 18 months, so he only breeds every other year.
Emu with young chicks near Cue, inland Western Australia.

Father and older chicks, northern Flinders Ranges, South Australia.
All more modern birds have feathers which 'zip together' by tiny hooks on the barbules along the edge of each barb, hundred of which branch from the central vane, or rachis. In ratites these hooks are missing, so the plumage is much looser and more hair-like than we're accustomed to seeing in a bird. An Emu can be somewhat reminiscent of a haystack in fact.
Shaggy Emu plumage.
Something else is happening here too though. Some birds, especially more primitive ones, have an aftershaft, like a small second feather, branching from the base of their feathers; passerines mostly lack them. They tend to be woolly and it seems as though their purpose is primarily insulation. In Emus however this aftershaft is the same length as the main shaft, and in fact it is generally not clear which is which. You may get a sense of it in the photo above, but here's a single Emu feather. They share this oddity with cassowaries, which are in the same family.
Emu feather; the aftershaft is as long as the main shaft.
In kiwis and cassowaries, the plumage is much coarser and hairlike, probably for waterproofing, at least on the exterior; the underfeathers tend to be woolly.
Southern Cassowary Casuarius casuarius, Etty Bay, north Queensland.
One more thing on Emu plumage; they have a somewhat curious 'part' down the back, with the feathers falling away on either side of it.
Emu drinking near Esperance, Western Australia; note the conspicuous part along the spine.
All ratites have three toes, except for ostriches, which have reduced that to two. All except the forest-dwelling kiwis and cassowaries are birds of the open plains, and all except kiwis are runners. All of these can easily maintain speeds of 50kph, and the smaller rheas up to 60kph; an ostrich when pressed however can reach 70kph. 

Emus and cassowaries are in the same family, but the other groups each form their own family. There are three species of cassowary, all found in New Guinea, while the Southern Cassowary is also found in the rainforests of north Queensland, to where it doubtless walked during a glacial period when Torres Strait was dry - this last happened only 10,000 years ago. Their most obvious characteristic is the tough flexible casque on their head, whose purpose is still debated. It was supposed that it helped in running through dense vegetation, but there is no evidence for that. Captive birds have been observed using it to shovel litter aside, and it probably also has a display purpose, along with the colourful neck wattles.
Southern Cassowary, Mount Hypipamee NP, north Queensland.
Cassowaries are primarily fruit-eaters and are important vectors of rainforest fruit seeds. It has very recently been shown that the seeds of the Javan Ash Ryparosa javanica, a rainforest tree from north Queensland, germinate far better if fed first to a cassowary. In fact, over 90% of seeds taken from cassowary droppings germinated, compared with only 4% of uneaten seeds. Javan Ash seeds incidentally have one of the highest levels of cyanogens ever recorded in a plant, but presumably the birds pass them through quickly enough and without breaking the surface of the seed, so that they are unaffected.

In Africa there are two ostrich species, as the result of a recent recognition that the Somali Ostrich of far north-east Africa is a separate species, Struthio molybdophanes, from the much more widespread Common Ostrich S. camelus.  They are the world's largest birds, males standing up to 2.75 metres tall and weighing close to 150kg. Unlike other ratites males and females are very different; males are far larger, but are also black and white, compared with the females' duller grey-brown tones. 
Male Common Ostrich, West Cape NP, South Africa.
There are five species of New Zealand kiwis, relatively small forest-dwellers with characteristic long down-curved bills and highly developed senses of smell for finding worms and arthropods in soil. They are primarily nocturnal, though this may be only since the advent of humans and associated predators. They form a life-long pair bond; a kiwi's egg may be 25% of its body weight, making it the largest of any bird.

North Island Brown Kiwi Apteryx mantelli;
photo courtesy Wikipedia.
In South America there are three species of rheas, though until recently only two were recognised. Rhea was the mother of the classical Greek gods and goddesses, but we have no idea why Paul Mohring, the German biologist, applied the name as a genus in about 1750. While brooding, the male is very aggressive, to the point that once he’s started brooding further females laying eggs must leave them outside the nest, and leave him to pull them in. Their food focus is on broad-leafed plants, but they also eat seeds, roots, fruit, insects, and small vertebrates. As ratites go they are relatively small, only a metre tall and with relatively long wings; this enables their very impressive turn of speed.
Darwin's Rhea Rhea pennata and chick with Guanaco (which gives an idea of how relatively small the bird is)
Torres del Paine NP, southern Chile.

Darwin's Rheas near Punta Arenas, on the Strait of Magellan, above and below.

There were apparently seven or eight of the mighty elephant birds of Madagascar, in two genera; the largest of them stood three metres tall and weighed up to half a tonne. They survived until recent times, until the arrival of humans, who presumably hunted them and their eggs to extinction. They were certainly present within the last 1000 years, and there are accounts attributable to them much more recently than that. 

The same sad tale could be told of the nine New Zealand moa species, the largest of them standing a colossal 3.6 metres high and weighing close to 250kg. Unlike all other ratites they had lost even their vestigial wings; presumably as forest-dwellers they were not runners and had no need of them for balance. They disappeared only some 600 years, overhunted by the newly arrived humans.

The conventional story of ratites is that they are a classic example of old Gondwanans, scattered across the southern lands as the continents took them on their journeys. That is the story I want to examine next week - be prepared for surprises if you've not hitherto heard this one!

BACK ON THURSDAY
 (And remember that you can get a reminder when the next post appears by putting your email address in the Follow by Email box in the top right of this screen.)