Death & sibling rivalry

Both birds eyes crop better again

The sibling sparrowhawks in their favourite tree… in my backyard!

It’s happened. Our babies, only three weeks or so out of the nest, are now out there in the big wide world, killing for themselves.  It brings a tear to your eye.

Distant with second bird flying crop

Keeping an eye on little brother or sister

But it’s not all cheery dismemberment:  there’s trouble in the nest.  The siblings to have an uneasy relationship.  I often see them perched on adjacent branches, and when they’re further apart they call out to each other every now and then.  And when one takes off to hunt, the other often falls into line, disappearing suddenly in a simultaneous dive.

But there’s also a certain amount of what might be described in human siblings as petty jealousy.

Yesterday I stood on a chair on the deck for an hour watching one of the sibs engage in  a comprehensive preening session / extended tai chi practice.  I wonder whether this serious self-care might have been the consequence of getting tangled up in one of the humungous org spiders webs stretched out between the trees to catch dragonflies, cicadas and, for the really ambitious arachnid, a passing sparrowhawk.

Preening headless profile tail out crop b&w

… and the headless sparrowhawk

I found the “revenge of the headless raptor” impressive, but his nestmate, looking on from a high branch, seemed rather unimpressed.

Distant top brother looking down b&w

Jeering at silly sibling

But both martial arts and sneering were set aside when the fledgling in the upper branches spotted something tasty beyond the neighbour’s yard.

Juvenile sparrowhawk wings raised square

I’m off…

There was a simultaneous stoop, and then a fracas in the jungle at the bottom of the garden.

White cheeked honeyeater crop

Dinner… a white cheeked honeyeater I prepared earlier

I don’t think the squawking was the work of dinner – an unfortunate white-cheeked honeyeater (rarely seen in our yard.  I wonder why…).  I reckon the ring-ding battle was between the sibs.

The winner landed, very conveniently for me, right next to my washing line, showing the total indifference to human proximity that seems to characterize most young raptors.

 

Sparrowhawk profile left with untouched prey

The lucky sibling with significantly less lucky white cheeked honeyeater

This diffidence did not extend to the presence of little brother or sister though.

Juvenile looking behind for rival

Keeping an eye out

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Juvenile with head turned mouth open amended

 

Just a few moments after the winner landed with their prize, there was another skirmish.  Luck favours the prepared, and this youngster was in position, with wings spread out protectively around the prey like a sort of meat umbrella. Ew, what a nasty image.

The hungry one had another go, and to be honest, I’m not really sure who was successful, since neither juvenile has any distinctive marks (like a scar over one eye or a dragon tattoo or anything) I am completely unable to tell them apart.

Juvenile plucking the prey

Settling in for a good plucking

Anyway, someone had a lovely meal of raw songbird and someone sat nearby looking on and feeling sorry for themselves.

Sibling watching

Luckless sibling looking on at the feast

Nevermind, buddy.  I’m sure there’s be some tiny, tasty, rather slow birds on the menu for you sometime soon.

The backstory of the serial killers in our backyard…

The new generation of sparrowhawks emerges from the nest…

Baby brush turkeys versus nestling sparrowhawks… the battle of the backyard baby birds

The collared sparrowhawks return to our backyard… or are they brown goshawks?

A first glimpse of the sparrowhawks… and a beautiful white goshawk visits the washing line

Things to do with termite nests

lizard in kingfisher nest better crop

Lace monitor in an arboreal termite nest

Happy New Year!

I don’t know about yours, but one of my resolutions for 2018 is to pay a lot more more attention to bugs.  Or rather, insects in general, and how they interact with all the other critters around them.

So the year was off to a good insect-oriented start when I took this photo  just down the hill from the spectacular lookout at West Head in Kuring-gai Chase National Park.

What’s this little monitor doing as she peeps out of this termites’ nest, a few metres up a gum tree?

What’s her story? And what’s she up to with those termites?

Lion island from west head

View north from West Head

 

At first, I thought she might have been after kingfisher eggs or nestlings.

A couple of years ago my bird watching brother told me to keep an eye out for termites nests in trees, pointing out that kingfishers often made the hollows in these “termitaria” to nest in.  Since then, I’ve seen plenty of arboreal burrows on my paddles around the Hawkesbury, and occasionally a sacred kingfisher lurking suspiciously nearby.

Many species of kingfishers, including (to my great surprise – I’m not sure why), kookaburras, often nest in termite mounds.  I had assumed that birds would choose abandoned arboreal termitaria, but in most cases where animals reuse mounds, it seems, the original builders are still in situ when the new residents move in.

Matching kookaburras

Synchronised kookaburras

Unlike other birds, such as the hooded parrots of Arnhem Land, kingfishers don’t wait to build until the mud of the mound is softened by rain.  They do construction the hard way, through sometimes lethal collision flights into outer wall of the nest.  Both members of the pair participate in this headbanging activity until a 25 cm tunnel is dug.  As you can see in the picture of the burrow above, the tunnel slopes downward a little, to help with keeping the it clear of the young’s faeces.  If only dealing with human children’s ordure was a simple as a gently sloping bedroom and hallway, eh?  Once the initial tunnel is dug, the kingfisher sometimes leaves the excavation for the termites to tidy up inside, sealing the interior walls of the nest.

Kingfisher lit profile sharp bigger crop better

New Zealand Sacred Kingfisher

But kingfishers aren’t alone in using termite mounds as a handy place to breed.  I’m not quite sure what was using this big nest near Port Stephens.  I suspect it’s not kingfishers.  Like many Australian birds, they are cooperative breeders, with their youngsters from previous broods helping raise the new babies, but they don’t seem to nest colonially.  As these burrowholes or just access points for some insect-eating predator to have a crunchy snack?

But back to our termite loving monitor lizard.  As a bird-savvy informant pointed out, had my lizard been munching baby kingfisher eggs, the parents would have had something to say about it.  In fact, what I saw wasn’t a nest-raid but most likely the aftermath of a hatching.

Monitor lizard face closeup

Another lace monitor in Kuring-gai National Park

Because, as it turns out, lace monitors  also lay their eggs in termite mounds, using the warmth generated by the insects to incubate their young.  Once the eggs are laid, the lizards lets the termites seal them in, safe from predators in their incubation chamber in the treetops. Or perhaps slightly safer.

No-one seems to research lace monitors – too damn common it seems.  But, researchers studying the related Rosenberg Monitors found that females defended the nests for a few weeks after the eggs were deposited.  Some hard core conflict was observed:

“The most aggressive fighting observed was between a defending female and a marauder, with females fighting males more than twice their body mass. Both attacker and defender sustained injuries, including dislocated or broken limbs; broken ribs; spinal injuries; and severe bites to head, throat, and abdomen” (Rismiller, McKelvey, Green, 2010).

Baby rosenberg monitors dig their own way out of their natal termite heap, but everyone’s a bit vague about how the baby lace monitors escape their birthplace/prison.  Despite the female’s willingness to break a spine or limbs to ensure the safety of their young at the point eggs are laid, herpetologists don’t give goanna mothers a lot of credit for subsequent interest in their offspring.  Some researchers think that the mothers come back to dig their babies out of captivity when the right time comes.  Others seem to think they just happen to be digging randomly in likely-looking termite mounds when they accidentally happen upon their young (Kirshner, 2007).  This sounds all rather implausible to me .

Goanna whole against lichen

Lace monitor in Wollemi National Park

I’m still not 100% clear about what I saw up a tree at West Head.  Was the lizard I spotted was one of the little ones, lolling around in its birthplace after its mysterious liberation.  Or a female spending some time hanging out in the nest, having helped her young to freedom?  I’m just not sure.

One way or another, one of our common-as-muck goannas was doing its thing in its ordinary, fascinating way.  With the help of a multitude of insect Mary Poppinses.

lizard in kingfisher nest distant

The termetarium from a distance

Further references

Kirshner, D. (2007) Multiclutching in captive Lace Monitors, Varanus varius. Mertensiella (16): 403-421

Rismiller, P.D., McKelvey, M.W., Green, B. (2010) “Breeding phenology and behavior of Rosenberg’s Goanna (Varanus rosenbergi) on Kangaroo Island, South Australia” Journal of Herpetology 44(3):399-408. 2010

 

 

 

 

 

 

The river that knew

Mist and sky above Mooney Mooney Creek better

Looking upriver from the junction with Floods Creek

If I want a quiet morning on the Hawkesbury, my best bet is a paddle up Mooney Mooney Creek.  It’s a jet ski free zone, and that’s a very fine thing. In maybe ten jaunts on various reaches of Mooney Mooney, I’ve seen a handful of kayaks, a few fishermen and one very slow moving yacht.  Unlike Cowan Creek or Patonga, there’s no sandy beaches for frisking about on, and the oysterfarms can be navigational hazard at low tide. But if you prefer hanging out with eagles and herons to spending time with humans in charge of powerboats, Mooney Mooney Creek’s the go.

Azure kingfisher profile crop

An uncharacteristically still azure kingfisher

There are really three Mooney Mooneys, for my purposes anyway.  There’s the upper reaches, a pleasant morning’s paddle if you throw in tranquil tributary Flood Creek, lined with casuarinas and decorated with the blue and green streaks of kingfishers hunting (more on the scenes and ecosystems there in a future post).  The put-in for that trip is where the switchbacking Pacific Highway crosses the river, though if you paddle upstream you pass under the highest bridge in Australia, a symphony in soaring concrete.

Or you can go downstream, towards Lemon Tree Bay and maybe on a low-ish tide, see, on every bend and mudflat herons feasting, and if you’re lucky, spot a wedge-tailed eagle soaring overhead.

Herons in parallel back in focus

White faced herons hunting at low tide

Up there in the headwaters, you’ll often see other kayakers – there are sometimes guided tours to the area – and occasionally people camping, rather naughtily, by the side of the river.  The Great North Walk, that links Sydney and Newcastle, via most of the lovely places along the way including Berowra (of course), flanks the upper reaches of the river and once or twice I’ve heard voices of hikers walking along the track or crossing the suspension bridge that spans the top of Piles Creek.

Snake island backlit 3

Snake Island and Brisbane Water National Park

But I’d prefer to be paddling than driving and I’m a little bit lazy, so I usually put in my boat in closer to home, at Deerubbin, where the freeway crosses the Hawkesbury.  From there I paddle under the freeway and past Spectacle Island, stopping off to check out the Mooney Mooney spoonbill colony, and then upstream.  Once you get past Snake Island and Sailor’s Chest Point, there’s not much sign of human activity, apart from oyster poles.

But there’s plenty going on, even without too many of us humans around.  Last week’s outing was particularly rich in feathery encounters.  A masked lapwing family enjoying a day out by the water by the Mooney Mooney public wharf.

Comedy silver gulls ducking for crabs in the shallows near Spectacle Island.

Silver gull with crab square amend

A sacred kingfisher  in the morning sun near her burrow in an abandoned arborial termite nest.  She got so bored with me clicking away she had a nap.

A striated heron, one of the river side regulars, pretending to be a particularly striking bit of sandstone.

And further up the creek, the predictable but still wonderful sight of a pair of young sea eagles perched amongst the mangroves in the shallow waters of Fox Bay.

The young ones seem to be easier to get close to.  A bit curious and a bit clueless, perhaps, about strange legless creatures that float downstream with the tide.

Even in the peace and quiet, there’s a feeling that all the inhabitants of Mooney Mooney Creek know about us.  They know we’re there – mostly out of sight, maybe, but not entirely out of mind.  The freeway passes just behind the ridge much of the way up the valley. You see it as you pass Snake Island, the trucks and cars  appear briefly, lifted above the rocky escarpment.  Sometimes, further up the creek,  the wind shifts and you can hear the sound of the traffic.

I recently found out that the freeway’s original route went right through my tranquil paddling territory – along Pile Creek, to cross the river south of where the Pacific Highway runs.  Right through kingfisher country.

But someone in the National Parks and Wildlife Service in the late 60s or 70s stood up to the road builders and just said “No”.  No, you can’t build a bloody great big road right through the (then recently established) Brisbane Water National Park.  We’re not having it.  In the words of the surprisingly fascinating “OzRoads” website

This new route had a more expensive bridge and steeper grades than the preferred route but there was nothing the DMR could do about it.

And it’s not often you hear freeway builders say that.  I’d love to  know the full story of who in Parks fought the good fight with the Roads folk.  Everytime I paddle up Mooney Mooney Creek now, I’ll be thinking about them and saying a little thank you.

Sea eagle facing away profile crop

Other paddles from Deerubbin Reserve

Up the Hawkesbury to Bar Island

For the ambitious, further in the same direction to Marramarra Creek

Into the heart of Muogamarra National Park up the winding Kimmerikong Creek

Downriver under the gorgeous if structurally challenged Hawkesbury River Bridge

 

Further references

Boon, Paul (2017) The Hawkesbury River: a social and natural history CSIRO Publishing

 

 

Welcome back, beautiful stranger

Sparrowhawk square crop old

It shows a certain lack of character and imagination to be keen on raptors, but I can’t help it.  I love them anyway.  Even the whistling kites and white-bellied sea eagles I clock every single weekend out in my boat on the Hawkesbury give me enough of a thrill to  clog up my computer’s hard drive with a thousand pictures of them in every conceivable posture and mood.

So two years ago, when I caught this beauty in my backyard, I was beside myself with excitement.  It’s a collared sparrowhawk, one of three species of Acciper found in Australia, along with the very similar brown goshawk and the hauntingly beautiful grey goshawk.  So beautiful that on my one and only encounter with one (whilst pegging out the washing) my camera fainted and so in its barely conscious state was only capable of producing a groggy quasi-mystical image of the world’s only pure white raptor.

I know our beautiful visitor in 2015 was a sparrowhawk and not the very similar looking brown goshawk, having been schooled on the key differences.  Brown goshawks are slightly grumpier and more threatening looking, with a beetle brow and chunkier legs.  Both species, it is said, waggle their tail on landing, but the sparrowhawk does it a tiny bit more rapidly.  As my brother, a much more expert bird watcher than I am, points out, this has to be the most arcane and pointless advice for distinguishing two very similar looking birds.  “Sorry lads, the video of your tail waggling was slightly out of focus.  Can you just circle round and land side by side on that branch again?”

Collared sparrowhawks also have another feature – the absurdly long middle toe of the collared sparrowhawk, used to grip its prey while it systematically plucks them (starting at the vent) and then devours them.  It’s moments like these you’re grateful not to be a sparrow or a silvereye, isn’t it?

But is that enough to tell the difference between a goshawk and a sparrowhawk?  Both apparently have these long middle toes – the sparrowhawks’ toes are just longer and more delicate.

There are other differences too.  Goshawks have a rounded tail, and a smaller eye.  So is it welcome back stranger… or good to see you, lifer?

Both the collared sparrowhawk and the brown goshawk are widespread through their range in Australia and New Guinea – they can be found in arid areas as well as woodlands and suburbia.  They are one of the few raptors that will perch and hunt in gardens, as I saw today.  The fact that they’re partial to a snack on introduced birds like sparrows, starlings and newly hatched chickens (gulp!) may be one reason why they’re considered “of least concern” to people who worry about the current mass extinction event.

But still, they’re not exactly common. Numbers declined from the 1940s through to the 1980s thanks to DDT, although the effect of this insecticide – thinning the shells of eggs – seems to have been less dramatic for them than peregrines and some other raptors.  Loss of habitat for the small birds that sparrowhawks like to eat and competition from pied currawongs that will (somewhat implausibly to my mind) attack both adults and chicks are other threats.

It’s been a long couple of years since that last wonderful visit.

But over the last few days there’s been a new sound from the decrepit pine trees that stand (or should I say lean) between our place and our neighbours’.  At first I thought it was a whiny juvenile wattlebird begging for a feed – the call was a kind of feeble high pitched kik-kik-kik-kik.  And then I saw a creamy coloured bird with wide striped wings and a blunt head, superficially like the “green” satin bowerbirds that hang around here all year round scrounging off my chilli bushes and demolishing my bean plants.

But there’s something distinct and decisive about the way raptors fly.  I eventually got a good look as the bird chilled out in the trees, waiting to ambush passing little passerines, which they catch on the wing.  I’m really hoping they have a taste for noisy miners.

good sideways distant crop wide

These really are very low-key birds.  “Often lives unnoticed in mature-treed suburban parks and gardens” one ornithology site comments about sparrowhawks… “easily overlooked”.  Having spent quite a bit of today staring slightly hopelessly into the naked branches for an immobile, unconcerned and well camoflaged bird of prey I can confirm this.   “Trusting and approachable“, the Peregrine Trust’s turn of phrase for a collared sparrowhawk, seems like a slightly embarrassing description for a predator.

Sparrowhawk profile crop tighter still

A gorgeous profile on display.  One very chilled out bird.

The grumpy reputation of Brown Goshawk is apparently not just a consequence of their Resting Bitch Face.  They’re also apparently quite aggro around the nest.  True to form, sparrowhawks are said to be calmer.

Perhaps this parental behaviour will be the solution to my ID problem.  There’s a nest made of sticks high in the neighbour’s pine tree, a spot I saw the sparrowhawk returning to several times today.  If there’s anything better than grown up raptors in your backyard, it’s a clutch of baby raptors.

nest rop

Could this be a sparrowhawk nest?

Join the war effort: grow your own luffa!

Given my history of coldly executing generations of zucchinis in babyhood, it was a high risk endeavour to attempt to grow luffa.  But the charmingly named “dish-rag gourd” is described on-line as a “large aggressive climber“, and apparently is an invasive weed in Uganda.  So I thought I would give it a go.  In fact, maybe I should only attempt to grow plants that sound like they should be banged up for burglary and GBH.

Luffa is a dual utility crop, a bit like our big boofy chickens Shima and Apricot.  We don’t like to mention it when they’re around, but as well as being pretty good at layers, Barred Rocks (like Shima) and Light Sussexes (ie Apricot) make pretty good eating.  Allegedly.  We won’t do it, girls, we really won’t!

I’m not sure how toothsome baby luffa really are but there’s not many vegetables that can be used as a backscratcher, a pillow, a sound-proof liner for steel helmets, a device for cleaning car wind-shields or a filtration system for ship’s boilers, so perhaps we are asking too much for it to be haute cuisine.

Pearl Harbour was obviously a tragic event, but one little known casualty of the bombing of the US Navy was the sudden disappearance of luffas from bathrooms throughout America.  Japan had been the main commercial producer since the 1890s, and so when America entered the war, the luffa supply was suddenly cut off.  In the words of economic botanist W.M.Porterfield: “the same catastrophe that stopped their importation enormously increased the need for them” (1955, 212-3)  and the US War Production Board forbad their delivery, sale or use for anything except filtration systems for ship’s boilers.

I am quite grateful that I’ve not been required to turn over my luffa crop to the authorities for some kind of military emergency.  While I consider it to have been a success, that is relative to my usual abject failure on the gourd growing front.  I managed to grow four mature fruits from three plants.

Dried luffa closeup

Luffa are tropical plants and need a long growing season.  Given that my whole garden is plunged into shade around about the equinox, it was nip and tuck whether the fruits would get big enough to make a decent sized back scratcher. As with zucchini, you have to be patient.  The first rather lovely yellow flowers, appearing in mid-summer, were male and only very late in the season, just as I was about to give up on it as yet another curcurbit failure, did female flowers and tiny perky fruits emerge.

On the positive side, the little luffa plants proved very easy to move around the garden so they could follow the sun – from  little pots on the windowsill in spring, to hefty tubs on the sunniest spot on our patio.  Since they’re actually a pretty vigorous plants for growing in a pot, I ended up moving one plant yet again, to the base of my “black widow” trellis.  This spot had previously been the kiss of death for any vine I attempted to grow there.

Innumerable generations of passion fruit and even a choko plant have turned up their toes on that higgledy-piggledy bamboo lattice (what can I say: I’m a slow learner).  By some kind of miracle, the luffa survived despite the fact I violated innumerable transplanting by-laws by moving a metre long vine covered in leaves in the middle of summer.  It survived the chooks (more evidence that luffa are probably not worth eating), and produced a haul of three fruits.  Okay, Porterfield reckons 20 fruits per vine is “to be expected”, but I find it’s best to cultivate low expectations.

There are lots of videos on YouTube sharing advice on getting the fibrous “skeleton” out of the luffa gourd.  Which would have been more helpful if they weren’t a sequence of mutually contradictory tips.  The smart money seems to be on leaving your luffas to dry as long as possible.  Some of mine dried out a bit while hanging on the vine, but I left the rest on a sunny windowsill for a couple of months.  In theory that skin should go hard, brown and leathery and then you can just peel it off, shake out the seeds and voila, there’s your luffa.

The alternative suggestion for those who were too impatient to wait for dry skin or, whose luffa (like mine) seemed likely to rot away in the meantime, involved cracking and carefully peeling off the skin and then squeezing and massaging out the remaining flesh and seeds in a bowl of water.  Whacking the flaccid luffa a few times on the sink to help shift the flesh was also recommended by one YouTuber.  The whole thing had a faintly sordid feel, like some sort of low rent vegetable s&m club, but did seem to work reasonably well in the end.  After a few days of drying out on the windowsill, I now have a suite of firm, fibrous and faintly grubby looking luffa that my children will no doubt refuse to have anything to do with.

So what’s new?  The vision of excited children running into the verdant backyard to pluck ripe organic snowpeas and strawberries has never really gelled with the scorched earth look of our chicken-denuded yard and proliferation of high-security possum-proof vegetable beds made of wire sock drawers found by the side of the road.  So I’ll let yet another self-sufficiency fantasy go.  The kids will remain (un-ex?)foliated but I’m still a seed saver – I’ll give “the dishrag gourd” another go.

 

References
Porterfield, W.M. (1955) “Loofah: The Sponge Gourd” Economic Botany, Vol. 9, No. 3 (Jul. – Sep., 1955), pp. 211-223

 

The shortest days and how to use them

The chickens let us know when midwinter’s come.  The fortnight after the winter solstice, no matter how bloody cold it is, the girls start serious egg-laying.  So even as you’re trying desperately to stash four different kinds of hot lemon pickle and a hundredweight of lemon marmalade, as you open the fridge, a dozen eggs roll out.

Lemon preserves cool closeup skinny

I went AWOL from the blog for the last six months, as the observant amongst you might have noticed.  The days just got shorter and shorter.  My garden kept growing and the Hawkesbury streamed uninterrupted to the sea, but time to write about these things just seemed impossible to find.  But now the days are lengthening (and I’ve finished my night classes), all that is going to change!

Eagle flyby long crop

White bellied sea eagle doing a fly-by of Gunyah Beach

The shortest day may have passed but it’s still pretty nippy at 5.30 in the morning when I get out of my lovely warm bed and drive off through the nautical twilight to put my kayak in the water.  When it’s 3 degrees and you have wet feet, the exact moment when the sun touches your frozen toes comes to be of critical importance.

I have a nifty little app on my phone, SunCalc, that shows just where the sun will appear over the horizon on any day of the year.  So I check the tide, and the wind, and then, on a winter morning, figure out where I’ll catch the very first light.  Putting in at Brooklyn and heading for open water is not a bad choice.

I’ve had some lovely paddles from Parsley Bay in the last year.  Quiet jaunts into Porto Bay, a shallow backwater frequented mostly by raptors and oyster fishermen…

Juv sea eagle long

Juvenile white bellied sea eagle

And, on a day with hardly any wind, I braved it across to West Head, stopping off at four beaches – Gunyah on the way and Eleanor on the way back; and on the other side of Cowan Creek, Little Pittwater with its tumbling stream and littoral rainforest and Hungry Beach and its a pair of sunbaking sea eagles.

Terns in front of Lion Island cropped closer small

Terns fishing off Gunyah Beach

I was almost bold enough that time to cross the invisible line – “limit of flatwater sailing” – that passes between Juno Point and Flint and Steel Beach, but bottled it in the end, just peeking round the corner towards Pittwater and the open Pacific beyond.

Clouds over the sea long and skinny

And last weekend, coldest it’s been on a Sydney morning in a couple of decades, I set out for Refuge Bay, where the pleasure craft rocked quietly, their skippers sleeping.  But not the kids, slipping away in their dinghies to fish and play under the waterfall on the beach.

And on journey there, what magic scenes!  The open waters of Broken Bay skimmed, concealed, curtained, framed, illuminated, by the fog.

Fishing boat and lion island

Fishermen and Lion Island

If there’s something to be said for the shortest days, it’s the long nights.  You can almost have a sleep-in and still get up before dawn.

Juno head mist dark sky

Too hot to handle?

floppy-claw-small

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.

echidna-great-face-for-crop-2-small

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