Bearded Mountaineer: BACK WEDNESDAY 3 OCTOBER

This bearded mountaineer is not what or who you may have expected. It is an uncommon hummingbird found only in the high Andes of southern Peru. This one surprised me by feeding on Tree Tobacco, Nicotiana glauca, which is a common weed in inland Australia, but native to that area. (Surprised only because of its Australian associations for me.)

Note the purplish 'beard' standing out from the breast.

As my other heading suggests, I'll be away now until next Wednesday. (We're driving up to Armidale, about 800km north on the New England plateau, to attend a wedding. While willingly fulfilling my responsibilities, I'll make a bit of time en route, and in Armidale pre-wedding, to do a bit of natural historising - I'm sure you'll hear about it.)

Spring Wildflowers (3)

Unexpectedly I had an hour to spare yesterday between engagements near Black Mountain (dry eucalypt forest near the centre of Canberra) so I did a short walk near the summit. In particular I wanted to see if the spectacular Golden Pomaderris were flowering, and I was duly rewarded. Most Pomaderris have relatively inconspicuous flowers, white or greenish; moreover they tend to live (around here at least) in wet mountain gullies. This one, Pomaderris intermedia, defies both those generalisations. In fact I strongly suspect that many people, understandably, mistake it for wattle from a distance.

Another welcome addition to the spring celebrations is Nodding Blue Lily, Stypandra glauca, one of the first of the forest lilies to appear here.

The last two I want to share are both much less conspicuous, as is the wont of the family Euphorbiaceae, known here best for weeds such as Castor Oil Bush and the spurges. (An exception is the coastal Wedding Bush, in being both native and spectacular, which I featured recently under Nowra Flowering.) The flowers of both these following species are tiny, only millimetres across. 

Thyme Spurge, Phyllanthus hirtellus, above and below.

 

Small Poranthera, Poranthera microphylla.

I think there can be as much satisfaction - and beauty - in these tiny and oft overlooked species, as in their flashier neighbours.

Plenty more to come in this series, as October looms!

Bored? Ah Frigate, Let's Catch a Bird...

It would be fair to say my flabber was gasted by this story this week. Briefly, it laments the apparently imminent passing of the 'hobby' of frigatebird catching on the Pacific Island of Nauru. The closest it comes to explaining why it happens is when the subject of the story, a Mr Gioura, one of the last practitioners, tells us that the captured and tamed birds are sent out to sea - to bring more frigatebirds back... It's not for me to question others' cultural practices, but it does sound like a symptom of too much spare time and no internet connection.

I have read elsewhere however that some Pacific islanders have traditionally used tame frigatebirds to carry messages between islands (though having reported that, I'm not too sure about the status of written languages in pre-European Polynesia). Even without such drastic measures as those advocated by Mr Gioura, frigatebirds have become accustomed to humans and their scraps around ports.

male Magnificent Frigatebird perched on the fish market roof, Puerto Ayora, Galapagos

As for the birds themselves, they are close to being the world's ultimate aerialists, far more at home on the wing than on land or water. The Magnificent Frigatebird of the American tropics may have a wingspan of close to 2.5 metres, to carry a weight of just 1.5kg; this gives them probably the lowest wing-loading (weight carried per area of wing) of any birds. All flying birds shed as much weight as possible, with hollow bones, but a frigatebirds has carried this to a wonderful extreme - its entire skeleton provides just 5% of its entire body weight! By contrast the great flight muscles make up a quarter of its overall weight.

Magnificent Frigatebird silhouette, Galapagos.
The long forked tail and the very long slender wings are the keys to its aerial virtuosity.

Frigatebirds are famous - or infamous - for their piracy, when they use their extraordinary aerial power and agility to harass terns and boobies coming back to the breeding colony to disgorge their load of fish. They are indeed very good at it, but really they work for an honest living most of the time, seizing fish and squid from the sea surface. Perhaps appropriately, they are especially partial to flying fish.

Some places in tropical and near-tropical Australia are particularly good places to enjoy them (if you're not a tern). One is Lady Elliott Island, north-east of Fraser Island, where they roost in trees around the shore near the sole resort.

Greater Frigatebirds (male above, female below), Lady Elliott Island.

Another is Weipa, a bauxite mining town on the west side of Cape York Peninsula, in far north Queensland. Here the birds swoop down thrillingly to drink from the flooded tailings dams at the edge of town. I reckon this is one of the most exciting bird experiences in Australia, but it isn't widely known.

Frigatebirds, both Greater and Lesser, drinking at evening, Weipa.

Males of all five species inflate their remarkable throat pouch, which is an adapted air sac, normally a key part of a bird's breathing system, in courtship displays. Sadly this one wasn't interested in impressing me.

male Magnificent Frigatebird, Puerto Ayora, Galapagos.

To finish, I have an abiding memory of the frigatebirds at Weipa, scores of them hanging nearly motionless high above the mangroves, drifting on the air until darkness took them. And I've never had the least inclination to catch one...

Idyllic Idalia

I have many favourite parks, in Australia and elsewhere, and for no good reason I want to introduce you to one today - assuming of course that you've not already had the pleasure. Idalia National Park, in central Queensland, is south-west of Blackall just south of the Tropic of Capricorn. For those not familiar with Australian or Queensland geography, here's where it is. (Look for the red arrow!)

We were last there in April a couple of years ago, when things were still pretty dry (but read on!), so not many flowers to share this time. It is close to the eastern edge of the Mulga lands; a quarter of the whole of Australia is dominated by communities associated with this species, Acacia aneura.

Mulga plains from Emmet Pocket Lookout, Idalia NP.

Mulga, Idalia NP.

Mulga flowers.

We spent time walking and driving slowly, but also just sitting quietly at water holes, especially Murphy's Rockhole, in the rocky ranges.

Bar-shouldered Doves

White-plumed Honeyeater.

Spiny-cheeked Honeyeater.

Euro (Macropus robustus). This is a large, rugged, shaggy kangaroo of the rocky ranges, found over much of Australia.

The Euros are common in the park, and always appreciated by us.

Young Euro, Idalia. The shaggy fur and big ears are obvious.

However, as well as this common kangaroo, Idalia features one of the rarest and, in our opinion, perhaps the most beautiful of kangaroos. The rock-wallabies are a specialised group of small kangaroos which specialise in living in boulder piles and sheer cliff faces; where Euros power up a cliff, rock-wallabies flow, like running water. All rock-wallabies have suffered from isolation, from 19th century hunting, and especially from introduced Red Fox predation. Yellow-footed Rock-wallabies survive only in the Flinders and Gawler Ranges of South Australia, near Broken Hill in New South Wales, and in the Idalia region. Here they are relatively easy to see.

Yellow-footed Rock-Wallaby, Idalia NP.

This phasmid, or stick insect, was huge - at least 15cm long - but I can't identify it.

In camp, Hall's Babbler, another much sought-after species by bird-watchers (it was only described in 1964), is a regular visitor.

Hall's Babblers, Idalia camp ground.

It was in camp that things went wrong for us, after a rather nice camp-oven roast dinner.

At 3am we were woken by several centimetres of water rushing through the tent (so much for drought); to cut a long soggy story short, we 'slept' the rest of the night in the car, and by early afternoon when the rain eased off, made a break for it - we were the only ones in the park, including staff, and all our bedding was sodden. It took some five hours in low ratio four wheel drive to do the 80km to the bitumen. I can't offer you any pictures of it, partly because I didn't dare stop, and partly because my camera was a victim of the deluge. Nontheless, we'll certainly be back, and I'd recommend you visit if you're in the area. Four wheel drive is preferable, but as long as it's dry you'll get in and around with a two wheel drive in reasonable condition. Check the forecast though...

Moon over the Coolabahs; I didn't want to end on even a slightly negative note!

Spring Wildflowers (2)

This is the second in an occasional series of posts in which I celebrate, and share with you, the spring flowering in what we like to think of as the Bush Capital. If people associate Canberra and flowers at all, it's likely to be in the context of Floriade, an annual display of mostly European plants, or perhaps the magnificent National Botanic Gardens. However the forested hills and flatter woodland reserves that lie throughout the city have superb floral displays in spring.

As spring progresses and I post more in this series, I'll limit myself to flowers which have emerged since I was last out, so I won't be repeating species. The last couple of weeks have been dry, and it's only starting to warm up now, so progress is still a bit slow.

Mountain Grevillea, Grevillea alpina. A small-flowered Grevillea, this was until recently
considered to be a separate but related species to G. alpina, but is now generally
regarded as the same. However in the Australian Capital Territory it mostly only grows on Black Mountain,
and the main population is well to the south in Victoria.

Like the first posting in the series, these photos were taken on Black Mountain in central Canberra, on a short walk yesterday as we zipped between other engagements. For the rest, the flowers are quite capable of talking for themselves.

Waxlip Orchid, Glossodia major. A handsome fairly large orchid,
widespread in south-eastern Australia. I'm always delighted by the first one of the year!

Rhytidosporum procumbens, an elegant little shrub in the Pittosporum family, which is so modest it
hasn't even attracted a generally-used common name! Ants are notorious
nectar thieves, and you can well see that these tiny miscreants aren't going to
touch the pollen on the pink-tipped stamens. The whole flower is probably only 10mm across.

Dillwynia retorta, one of the parrot-peas, so named for no evident reason.

Finally, another firm favourite of mine, the beautiful Twining Fringe-Lily,
Thysanotus patersonii. Just love those fringed petals!

Another instalment in a week or so, as things start to pick up - October is the peak flowering month around here.

Shell Be Right; an eggciting history

Today I have eggs on my mind. (Some might say that this is because my mind is scrambled, but fortunately they're not writing this.) It started when we went out for breakfast in the sun at the cafe at the National Botanic Gardens, long a favourite of ours. Unfortunately the new management seems to be still finding its way and, after an hour, during which we reluctantly sent back stone cold (but cooked!) eggs twice, we gave up and went home to cook our own. 

However it was not all a disaster, as it did get me thinking about how wonderful is the too often taken-for-granted egg, in its original state.

Emu eggs, south-west Queensland.
(For some reason all these pictures are old, scanned from slides -
my apologies and I must make an effort to take some nice digital egg pics!)

Essentially all female animals lay eggs, and have done so for hundreds of millions of years. Generally when we talk about eggs however, we're referring to amniotic eggs - the amniotes, put simply, are the group of vertebrates that include reptiles, birds and mammals. One of the most amazing inventions of  reptiles was the enclosing of the embryo in a protective shell. By cutting off the embryo from the world, and supplying it with a larder comprising a built-in food and water supply, these pioneering reptiles could move away from water and begin to take over the earth. The amniotic egg seems to have arisen some 320 million years ago.

Southern Angle-headed Dragon (Hypsilurus spinipes) laying eggs,
Lamington National Park.

A fabulous series of fossilised dinosaur eggs from six different species which between them lived from 146 to 65 million years ago reveals the developing sophistication of eggs, with increasing numbers of air cells and additional layers being added to the shell. In other words they were becoming more bird-like - hardly surprising given that birds are, for all practical purposes, living dinosaurs. 

The actual process of forming a bird's egg is remarkably complex and detailed; it's worth considering, albeit briefly. The yolk comes first; this is not, as sometimes supposed, the embryo, but it is the embryo's packed lunch; the embryo itself starts life as a small collection of tissues on the yolk surface. If the egg is not fertilised in the first 20 minutes of its life, too late! The subsequent inexorable addition of layers prevents it from happening. (Though except for domestic chooks - 'hens' for my non-Australian readers - this rarely occurs.) As the eggs slowly rotates, four layers of albumen - the white - come next during the next couple of hours; these provide both a stabilising cushion and a water supply. During the next hour the egg moves down a narrow passage where two layers of supporting membrane are added. They can be revealed by carefully peeling an egg.

White-naped Honeyeater nest and eggs, Tidbinbilla Nature Reserve.

Finally, the most labour-intensive and time consuming stage, the addition of the shell itself, takes some 16 hours. Crystalline calcium carbonate (which also makes up chalk, coral, snail shells etc) is deposited, along with a protein matrix to glue it together. Thousands of pores must also be provided, precisely sized to allow gas exchange between the embryo and the outside world, but to exclude micro-organisms. Pigments, both in the crystal structure itself, and as surface dyes, are also provided at this stage. If the egg is to be laid in a dark place, such as a tree hollow or a burrow, it will be white; if it is to be in the open it requires camouflage and the pigmentation can be quite complex.

Rufous Songlark nest and eggs on the ground, Goulburn River National Park.

Most eggs are oval - ie egg-shaped! - so that they roll back to the middle of the nest. Eggs laid in hollows or burrows can't roll away anywhere and can thus afford to be round - this is the most efficient shape in terms of least surface, and hence least shell material. Eggs laid on flat ground or on ledges tend to the most conical in shape to stop them rolling away.

Red-capped Plover egg and 'nest', Comerong Island.

The whole process takes about 20 hours. Only one egg is laid per day, to minimise excess weight in the mother who still needs to fly, unless she's an emu or a penguin, though a string of small yolks await the signal to start. She generally lays first thing in the morning, to reduce baggage for the crucial early morning food gathering, and to allow the fragile shell to develop while she's resting and still.

There is much more to be said of course, on both eggs and nests, and in time we'll say it. Meantime, if you're in the Southern Hemisphere there is likely to be a clutch of eggs not far from you at the moment; spare a thought for what's involved.

Black Caiman

Black Caiman, Manu River, Peruvian Amazonia

Back tomorrow! Happy weekend all.

'Tis a Tangled Web They Weave

One of the most extraordinary structures in nature (or out of it) is a spider's web. Spider silk is inconceivably fantastic; to say that it's a protein produced by a gland (spinneret) at the rear of the animal's abdomen really falls a long way short of conveying it. It is said that a strand the thickness of a pencil could stop an aeroplane in flight - and it's flexible! What chance does a moth have? Moreover there are seven types of silk, each produced by a separate gland in the spinneret; while no spider can produce all seven, some, including the orb weavers such as Argiope and Eriophora species, can produce five. Further these different types can be combined to form a huge array of threads of different appearance and function. Much more to be said on this in future postings!

However today I'm just going to comment on one type, prompted by a story about Korean researchers who appear to have resolved the function of  the wonderful ribbons of oddly conspicuous silk in the webs of some Argiope species, the most familiar of which in eastern Australia is known as the St Andrew's Cross Spider A. keyserlingi. I say 'oddly conspicuous' because it would hardly seem to be of benefit to the spider to make its food trap too visible.

St Andrew's Cross Spider in web, Nowra.
Some on-line sources report that this species occurs over much of Australia, but I trust the
Atlas of Living Australia which says that it is restricted to the east coast.

The ribbons are known as stabilimenta; at least eight other spider groups appear to have independently 'invented' stabilimenta. Their purpose has been debated, with the original suggestion involving strengthening and stablising - hence the name. Others include making the web visible to avoid accidental damage by large animals, breaking up the outline of the spider in the web for camouflage and reflecting ultraviolet to attract prey to the nest. This last suggestion is the one the researchers pursued, and indeed it appears to explain at least part of the purpose of the structure. This is based on their observation that the twenty families of large pollinating insects - including butterflies, moths, wasps, flies and beetles - caught in the decorated webs of a related Argiope species were twice as likely to be caught by these as by undecorated webs.

The key points here are that 1) the ribbons in the web reflect much more ultraviolet light than the rest of it does, and 2) we know that such insects are attracted to ultraviolet patterns reflected by their preferred flowers. The strong suggestion is that the spider is using this behaviour to lure the insects to their doom, and the spider's dinner table. Quite properly the researchers point out that this isn't necessarily the only purpose of the decoration, and may not even have been the original one, but this is how evolution works, adapting structures and behaviours for purposes as the need arises.

A closely related and similar Argiope species from Litchfield National Park, Northern Territory.
Note the characteristic posture, with the legs held in four pairs.

As Louis and Sir David - among others - have commented, is it not a wonderful world?

(The original article is here, but unless you have 35 euros to spend you can't have access to it! However it has been reported on elsewhere - just search for the title.)

On This Day 20 September - the national capital's lake started to fill!

The Molonglo River, once known as the Fish River for its richness, was in the early 1960s a stream flowing across the grasslands of the frosty Limestone Plains, still polluted by unmanaged heavy metal mining dumps at its headwaters at Captains Flat 50km away. The fish had virtually disappeared long ago. When Chicago architects Walter Burley Griffin and Marion Mahony Griffin designed the national capital 50 years earlier a major lake was always a crucial focal point, an essential element of their carefully designed landscape axes. Unfortunately politics and economics interfered and the Griffins never saw this part of their plan come to fruition, though Marion, who outlived Walter by 24 years, died only two years before it happened. 

It was on this day, on 20 September 1963, that the gates of the Scivener Dam finally closed and Lake Burley Griffin began to fill. (No one is sure, incidentally, why it is 'Burley Griffin' rather than just Lake Griffin, or Lake Walter Griffin - not to mention why Marion missed out either.) The lake is 11km long, but the focus of many Canberra naturalists, and especially bird watchers, is a wetland complex that formed at the eastern end, furthest from the dam. The Jerrabomberra Wetlands were not new, but their permanence was; previously they had been ephemeral, based around the paleaochannels of the Molonglo, which filled in times of high flow, and dried out during droughts. It is this aspect of the national capital's lake, rather than the national institutions which line it - library, museum, galleries, high court - that I want to celebrate today.

Kelly's Swamp, the focal point of Jerrabomberra Wetlands for birders, in evening light.

Jerrabomberra, a reserve managed as part of Canberra Nature Park, is included on a national Directory of Important Wetlands of Australia, as it is a crucial refuge for waterbirds in particular during droughts. Over 80 waterbird species have been recorded there, but the plantings which have been undertaken for screening and habitat make it important for many terrestrial birds too - my own list for the wetlands over the years stands at 135 species, which is more than half the birds I've seen in the entire Australian Capital Territory.

Undoubtedly the birding highlight in recent years was the advent of two Australian Painted Snipe late last year - this is one of the rarest birds in Australia and I'd never seen one anywhere. (One had turned up here a few years ago - I got the call when I was out of town but couldn't get back before dark. I was there at 5.30 the next morning, but it wasn't seen again... I actually almost missed these too - I arrived back from South America and was driven straight there from the airport!)

Other specials are the migrants which fly some 12,000km from the Arctic Circle to spend the southern summer here; among these, most celebrated is Latham's Snipe. It is a surreal and wonderful experience to sit in the hides and watch the snipe with the national parliament building in the background. 

The hides are well-placed and well-designed, to allow comfortable contemplation of the passing waterbirds. When my life wasn't going as I'd planned it (that was a while ago now) I spent many meditative and recuperative hours in the Jerra hides; they're a good place to go when life is good too though!

Great Egret

Royal Spoonbill in breeding plumage.

Glossy Ibis; one of many species not normally seen in our part of the world,
but which turn up at Jerrabomberra during drought times.

The hides shelter other mammals than bird watchers at times too.

Brush-tailed Possum and joey.

I mentioned land birds too, and one threatened species is often seen here. The Little Eagle is listed as threatened in both the Australian Capital Territory and New South Wales; a pair, one of the very few left here, includes Jerrabomberra in its territory.

Little Eagle at the sewage ponds just across the road;
these are ecologically an integral part of the wetland system.

If you live near here and haven't been out to Jerra recently - why not?! If you don't, make sure you put a couple of hours at least aside to visit next time you come to Canberra.

Happy Birthday, Jerrabomberra!