Too hot to handle?

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Although echidnas are pretty common, I’ve rarely seen seen them in Berowra.  So when I saw this one flopped out in the neighbours’ front yard on my sweaty walk home from work yesterday – ambient temperature in the mid 20s even at 7pm – I was worried.  Were echidnas, like fruit bats and stingless bees, troubled by temperature extremes?  Had this one been driven from its usual secluded haunts by this horrid heat wave?  Should I be on the blower to WIRES?

A cursory google did not inspire confidence.  Wikipedia notes that echidnas don’t sweat (in fact, they don’t pant, lick, or even wee on themselves and flap their wings to cool off either) and suggests that they “cannot deal with heat well“.  WIRES agrees that echidnas “cannot tolerate temperatures above 30 degrees“.

Notwithstanding, this seemed to be a very sprightly monotreme.  Most of the echidnas I’ve met have more or less fixed this position:

This beastie, however, was very busy, ignoring me and rummaging around in the flowerbeds.  Could it really be in trouble?  I decided, for the moment, that human intervention wasn’t necessary and then went home to check whether I’d just made a stupid decision.  Should I trust Wikipedia or my instincts?

I hit pay dirt when I found “Thermoregulation by Monotremes” by Queensland’s “Mr Hot Echidna”, Peter Brice.  As a researcher who has devoted time to  inserting “calibrated temperature sensitive radio-transmitters … coated with a smooth layer of inert wax… into the abdominal cavities of echidnas” (Brice et al 2002), he’s your go-to guy on this topic.

Niche subject as it might seem, the way echidnas and platypuses manage their body temperature has played an interesting role in propping up a hierarchical, human-centred view of evolution.  You’ve heard the story before, I’m sure. From this viewpoint, animals whose bodies are set up differently to us fancy-pants “classic mammals” are viewed as “primitive”.  Early twentieth century researchers decided that, for instance, that playpus had “an inadequate regulating mechanism” when after only 17 minutes at 35 degree temperatures, their research subject  “turned onto its back and fainted” (Brice, 2009, 260).  A poignant tale and the sort of thing that led one early twentieth century researcher to conclude that monotremes were “‘the lowest in the scale of warm-blooded animals’” (Brice, 2009, 256)

Don’t get me wrong, echidnas are very weird animals.  And that’s leaving aside the egg laying mammal business and the once-venomous spurs in their backwards facing hind legs.

Echidnas are cool. 31 degrees counts as a “normal” body temperature for them, though only females incubating eggs really keep their temperatures steady for long.  They seem to occupy a half-way house between warm blooded and “cold blooded” animals.  Echidnas don’t entirely rely on their surrounding environment to warm themselves as reptiles – ectotherms – do.  But unlike us humans – homeothermic endotherms – with our tedious need for a stable and predictable body temperature – echidnas can run hot or cold.

Just when you thought we were all “thermed”-out, you find that echidnas are also constitutional eurytherms – they can handle wide range of temperatures – and facultative endotherms – they warm their bodies up, in part, by doing stuff.

Echidnas also hibernate – well, some of them do, if they’ve eaten enough by the time the cold weather rolls in. But their hibernation, or its timing at least is, according to Brice (2009, 257) “distinctly odd”.  They often kip out during the late summer and then wake up to mate at coldest part of the year.  And they can deal with fluctuating temperatures in a way I can only envy – for instance, after a chilly night, they can dig their way out of shelter with their blood temperature of only twenty degrees.  With no bedsocks.

And they can also deal with a day spent in a hollow log at 40 degrees C without expiring from the heat, though no one knows exactly how.

We shouldn’t seeing echidnas and their wildly fluctuating temperatures as primitive, I reckon. Instead we should admire the way these critters harbour resources with their furry but weirdly chilly bodies, helping them live above the snowline in the Alps, in the desert and even on the sizzling streets of deepest surburbia.

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Echidna, close up and personal

References

Brice, Peter H. (2009) “Thermoregulation in monotremes: riddles in a mosaic” Australian Journal of Zoology, 2009, 57, 255–263

Brice, Peter H., Gordon C. Grigg, Lyn A. Beard, Janette A. Donovan (2002) “Heat tolerance of short-beaked echidnas (Tachyglossus aculeatus) in the field” Journal of Thermal Biology 27(6), 449-57

A flash of gold and a stash of blue

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Season of mists and mellow tinnies: the Hawkesbury in fall

Autumn lasted for aroundabout a fortnight this year.  The endless summer of an apocalyptic El Nino wrapped up in mid-May, giving the deciduous trees an extremely tight schedule to dispense with their leaves before this weekend’s torrential rain.

We’ve had autumnal glory in the kitchen as well.  When Keats talked about the “season of mists and mellow fruitfulness”, I’m not sure he was thinking about bananas.  In theory our crop of tiny fragrant fruits should have been perfect for lunchboxes, but I made the mistake of describing the first-ripened one as “Geoffrey”.   After this, not only Geoffrey but all his brothers were deemed “too cute” to be eaten.

As well as the gold in the fruitbowl, there’s been plenty of gold in the trees.  The yellow-tailed black cockatoos are back in force, mewling and crunching in the radiata pines.

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Fly by from a yellow tailed black cockatoo

And for the first time this year, I’ve noticed the migrating yellow-faced honeyeaters.  Thousands of them pass through the Blue Mountains most autumns, it seems, but this year they’ve been funnelled between the mountains and the coast, through the Hunter Valley.  I first spotted them darting through the riverside casuarinas at Karuah National Park, on our trip north, but since we’ve been back, I’ve seen flocks of them with their travelling companions, the noisy friarbirds, pouring up the Hawkesbury.  I’ve even seen them on the way to work, taking a moment out on their journey to watch the commuters boarding the morning train at Berowra Station.

But not all the autumnal excitement has been touched with gold.  Last weekend, halfway through detaining my broad beans (fencing, netting and a mulch of lavender and liquidambar – doubtless all in vain) I spotted a little collation of royal blue underneath the pomegranate tree. Nerf gun ammunition, the lid of a milk container, a peg.  Signs that we need to tidy up the yard, and a hint that randy bowerbirds might just do it for us.

 

More autumnal reflections from our backyard:

Let them eat light!

Autumn in terminal decline?

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Backyard gold

The silver river

Deerubbin – the Hawkesbury proper- doesn’t normally look like this: not when I’m there, anyway.  I’m used to the view out our back window: the valley full of fog, the hilltops islands in a foamy sea.

Hazy foggy view from deck

Mist over Sam’s Creek

You know the fog will be spilling across the highway as you swoop down from the ridgeline before dawn.  But when you reach the freeway bridge that stretches half a mile across the  Hawkesbury, the wind picks up and the mist is gone.

But not this Sunday.  The cloud was down and the river was silver.

Pixillated tinnie in distance

Fisherman in the mist

I’ve wrestled with this mist before.

I can say with confidence it’s not freezing fog, hail fog or upslope fog.  For all the salt in the air, it’s not coastal fog – moisture condensing over cool water – not with sea temps a balmy 24 degrees.  And is it valley fog? Damp cool air might slide down the hills in the night… but Sunday’s haze followed midnight downpours not clear skies.

Having thought about it rationally and analytically, I can only conclude that this was magical fog, sent to stop me paddling all way to the secret heart of this part of the Hawkesbury, Marramarra Creek.

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Big Bay

I’ve nearly made it there before, as far as Big Bay, with its great lagoon full of mangroves and the riverbed chocabloc with critters. No houses on the ridgelines, no way in except by water.  In the 1830s a surveyor’s wife didn’t think much of it: “these dreary solitudes might serve for the abode of a misanthrope so utterly are they secluded from all approach and so entirely destitute of all comfort”.  But I’m longing to paddle all the way to the source of the creek, through country with an indigenous past even I can read.

But this time it wasn’t just the fog and the march of time that stopped me.  The birds were in on it too, perching photogenically on the wayside oyster poles, feathery sirens luring me away from my upriver odyssey.

So I’ll have to come back to Marramarra.  Maybe next time I’ll bring our full flotilla of mismatched craft and camping gear and stay overnight halfway up the creek in the old orange orchard.  The noisy kids should to  scare away the temptations of the sirens… and, of course, the silvery silence.   So perhaps I’ll follow Odysseus and bring some ear plugs too!

Related posts – other paddles on the Hawkesbury from Deerubbin Reserve

Two sad islands, three whistling kites: a paddle from Deerubbin to Bar Island

Of gods and mapreaders: a trip up Kimmerikong Creek in Muogamarra National Park

A bridge fetishist paddles to Brooklyn: paddles up Mullet Creek and around Dangar Island

Broken Bay at low ebb: a short jaunt around the oyster beds near Spectacle Island at the end of Mooney Mooney Creek.

In other sandstone country

Wiradjuri country that is, or Dabee country to be precise: Ganguddy, on the Cudgegong River, that flows west off the Great Dividing Range, not into the Pacific but into the Murray-Darling.  Not far from Berowra as the Australian Raven flies – straight across the Wollemi National Park – but a fair trek in the excessively laden ancient vehicle.

Still sandstone though – the older, niftier sandstone of the Narrabeen Group, as it resurfaces at the very edge of the Sydney Basin, with the even older coal measures being mined perilously close byLayers of ironstone make for fabulous rock formations (if slightly less way out than the famous pagodas of the nearby Gardens of Stone National Park).  And of course exceedingly soggy tent groundsheets when big rain sluices off the rocks faster than even sandy soil can soak it up.

Same old sandstone geology, plenty of still water, just like the Hawkesbury estuary down our way, but the critters are different.  The feathered food thief at Ganguddy isn’t a brush turkey, it’s the purple swamp hen.

The “house bird” is a cheeky superb blue wren, not a wattlebird.  Rainbow lorikeets – not a one.  And none of those aggressive urban generalists, the noisy minors or the magpies, either.  Instead crimson rosellas – a rarity in the northern suburbs of Sydney – lurk in implausible locations like the queue for the drop dunny for instance, or the reeds by the river bank.

The ubiquitous but largely invisible bird here isn’t a koel or a channel billed cuckoo but the aptly named clamorous reed warbler.  I was at times tempted to nip to the Rylstone Guns and Ammo for a small flame thrower so I could finally get that photograph, but then I reflected that a perfectly focussed snap of a tiny blackened corpse clinging in its rictus to a reed probably wasn’t in the spirit of the thing.

A fabulous place.  It’s tempting, what with proximity to World Heritage listed Wollemi National Park and all, to think of it as a wilderness.  But no.  Its gorgeous waterways are the product of a 1920s dam built to to supply a cement works, its teeming fish the introduced gambusia affinis – the “plague minnow” – that outcompetes the locals, though it does seems to keep the mosquito population down.  As a camper it’s hard to argue with that, although we didn’t see a single bat, micro, macro or meso, during our five day stay.

There’s something to be said for human intervention, as Tim Low says.  In the absence of railway station eves or even a well put together shed, the welcome swallows in desperation had to resort to nesting on the natural stone outcrops.  But the local water dragons and turtles seemed to relish the fetid smelling pond downstream from the dam.

A tranquil place with a violent past.  A “natural” place shaped for a very long time by people in ways that you see and ways that you (or at least I) don’t know enough to notice.  A familiar story, on sandstone and otherwise.

Cloud inversions and sunsets: a year of backyard skies

Of snakes and snakebeans

This sight out the window as I stumbled into the kitchen for the first cup of tea of a Monday morning made the caffeine hit mostly redundant.   Snakey the diamond python’s back in town.

Last time we saw her was early spring a year ago. I looked up from the computer, wondering about the din the little wattlebirds were making, and there she was, stretching up for a sunny rooftop.

I’m worried about the timing of Snakey’s visit.  After a good five years of prevaricating, we finally decided to use rat poison near the house. You can predict and even understand when the vermin demolish your nearly ripe corn-on-the-cob – it’s almost obligatory for your quasi-rural pest population.  But when they won’t leave your broccolini alone it’s all gone too far.

Leaving the house on a late-night mid-winter drive, I saw a tawny frogmouth flash out of the dark.  Another evening a surprised visitor landed on the balustrade of the back deck, only to realise three humans, stock still with beers half-raised to their lips, were unexpected keeping the rodents away.  And we’ve seen Snakey wait, poised for hours, then suddenly strike a rat on a twilight mission for chookhouse grain.  A glorious sight.  But pythons might only eat one a fortnight – it’s that low energy lifestyle.  Sadly there’s no sign of such dietary modesty in the case of the sweet potato munching rattus rattus.

We tried humane traps too.  But what do you do with the terrified beasts, usually the littler, stupider ones, after their night in a cage?  Counsel them?  Release them in the nearest industrial estate?  Figure out some new, psychologically gruelling way of killing them, all the while deluding yourself that it might be somehow be painless?

So not so long ago we reluctantly, guiltily, laid down baits in inaccessible places and endured our penance, the smell of death.

So over my cup of Earl Grey, I anxiously inspected Snakey’s features for signs of toxicity.  She’d chosen her spot judiciously, beside our neighbour’s chicken shed and right above the rat run down to ours.   She looked torpid: had she taken a poisoned rat, one dying slowly and easier to catch than the others?  Wasn’t her jaw somehow slack and asymmetrical, her pose ungainly…?  All I can say is, don’t try phrenology or poker with snakes.  They are danged hard to read.

By the time I got home from work she was gone.  I must confess, in the subsequent days, I have become slightly more cautious with my footing as I head down to peg the washing on the line.

Snakey seems to have brought the subtropical summer with its run-to-the-washing-line storms.  I was that nervous commuter, glancing up at the looming alien mother-ship and hoping I’d get home before all hell broke loose.  Then, same thing, same time, next day. And the next. A regular 4 o’clock Apocalyse.

It’s like the Nile River Delta out back.  As you can see from the flood-art-installation above, every item a child or lazy BBQ tender has carelessly discarded in the backyard now has its own rich pile of alluvium.

The subtropical plants are glowing.  The tumeric has reappeared in the understory as just suddenly as the snake has in the vines.  It dies right down over the winter, and come early December, just when you think it’s a goner, the leaves start nudging through the soil.  Given my dodgy record with propagation, I’m specially pleased to see the this year’s young ‘uns.  Instead of wimping out and buying plants from the ever reliable Daleys, I buried some fresh rhizomes from my weekly organic veggie box and crossed my fingers.

Inspired the marvellous Sri Lankan cooking of my clever sister in law and her mum, I’m trying to grow the ingredients for my favourite mid-week meal of 2014, snake bean curry.  I probably don’t have the stamina to harvest and process my own tumeric powder, but thanks to the big rain, the “Red Dragon” yard long beans are leaping out of the ground, and my baby curry leaf plant – in a pot near the house where I can nip off its weedy berries and quash any suckers – seems to be doing well so far, despite attentions from a nearby lebanese cucumber.  Now, if only I could keep my coriander from bolting for more than 15 minutes I’d be ready to hit the kitchen.  With luck, I’ll still be under the steady supervising eye of Snakey.