Wildlife reboot: birds 2.0

Another January, and another trip to Ganguddy, on the western site of Wollemi National Park.  Same marvellous geology, same refreshing dam water, same hot weather.

But some things were different this year.  After the stupendously dry winter, the eucalypt forest was parched, the undergrowth sparse and the leptospermum flowers of last year’s visit few and far between.  We found a patch of sphagnum moss perched in a bowl of sandstone boulders so dry it crunched underfoot.

A “green” satin bowerbird panting in the heat

We spotted plenty of lizards, and the diggers were out in force – lyrebirds wandering through the camp as they tried to scratching their way down to moisture and a wombat turning up to twerk on a picnic bench.  But up in “kingfisher alley”, just before the Cudgegong River disappears into the reed beds, there were fewer blue and green flashes by the water.

Around the camp site, the bowerbirds and treecreepers panted in the heat.  Apart from the ubiquitous reed warblers, there seemed fewer birds altogether.  No sign of the friarbird teenagers of last year, and even the baby swamp hens seemed thin on the ground.

You have to wonder what it takes to change ecosystems irrevocably.  How many dry winters before the old inhabitants decide living and breeding here is just too tricky?  And who would move in to fill their place?

Back at Berowra after the trip, there are changes in the garden too… surprising ones.

We knew we’d be losing the sparrowhawks soon enough, but the family has dispersed in an unexpected orderThe adults disappeared off the scene weeks ago, and by the time we made it home with our ridiculously overloaded vehicle and small and ancient fleet of boats, the siblings had parted too.  There’s just one young’un now.  He seems lonely.

There’s a constant plaintive calling from the trees out back, that seems to intensify when he has prey on hand.  I’m not quite sure if he’s warning his imaginary sibling off or calling him to come and share a meal.

And that’s not the only shift in the soundscape around here.  The sparrowhawks have cut a swathe through the bird population on the premises.  Baby brushturkey numbers have fallen from previous plague proportions, noisy miners are few and far between and the “house” birds of yesteryear – red and little wattlebirds – are now just occasional visitors.

But as the numbers of resident raptors has dropped, a new set of critters have settled in.  Lewin’s honeyeaters which we’ve only seen once or twice in the backyard over the last seven years, have made our backyard their new home.  And we also appear to have acquired some brown thornbills, a raptor snack food if ever there was one.  And the local eastern spinebills, another tasty morsel for a sparrowhawk, are spending more time around here too.

The only explanation I have for the change of personnel is that the hawks have bumped the notoriously territorial wattlebirds, leaving the field open for new arrivals.

I’m pretty happy to have a new set of birds in the garden.  My dream scenario, I have to admit, would be to order up some songbirds that are a bit easier on the eye.  My birdwatching brother puts Lewin’s in a honeyeater “bin taxon” of pretty similar and drab looking birds it’s hardly worth distinguishing between.  Cruel, perhaps, but fairly accurate.

So, why not some new holland honeyeaters, for instance – gorgeous looking locals.  Or (still, my beating heart!) what about some pardelotes?  Just one or two?

On the other hand, it’s possible that all the vibrantly coloured small birds in the neighbourhood have been made into multicoloured meals over the past three months by our family of raptors.  After all, there’s got to be some evolutionary reason for all those SBBs*.

*note: this is a throwaway remark absolutely unsupported by any science.

 

Previous posts about Ganguddy

A bit about Ganguddy’s history and geology – and a little Tim Low on the side

Snakes versus whining teenagers – last year at Ganguddy

 

More on our sparrowhawk summer

Death and sibling rivalry

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

 

Further reading

Stephen Garnett, Donald Franklin, Glenn Ehmke, Jeremy VanDerWal, Lauren Hodgson, Chris Pavey, April Reside, Justin Welbergen, Stuart Butchart, Genevieve Perkins and Stephen Williams (2013) Climate change adaptation strategies for Australian birds: Final Report, National Climate Change Adaptation Research Facility

Office of Environment and Heritage, Premier’s Department (2011) New South Wales Climate Impact Profile Technical Report: Potential impacts of climate change on biodiversity

Black princes, redeyes and floury bakers

My brother the twitcher has taught me the secret of finding birds.  Tune into sound: let your mind move out from the place where you are standing, into the space above you and all around you and listen.

All this summer, I’ve been listening out for the sparrowhawks.  Even lying in bed or sitting on the sofa, we could hear them begging for food or squabbling with the local cockatoos.

But come mid December, white noise and static started interfering with Radio Sparrowhawk.  The cicadas had arrived.

This year’s a biggie for cicadas in Australia.  Over 350 species of cicada have been described here, though there could be many more – we’re a diversity hotspot for these charismatic insects.  And this summer, some of the biggest and noisiest species – the cherrynoses, the double drummers and the razorgrinders – have appeared en masse around Sydney.  After maybe five or six years of living metres underground sucking on the tree-sap, the cicada instars crawl out of the earth and shed their exoskeletons for a short and noisy month or so as adults.   It doesn’t happen every year.  2013 was a big year for cicadas in Sydney, and before that 2010.  And now it’s on again.

Black prince 1 closeup nice background

Black Prince on a casuarina tree by the edge of Berowra Creek

No-one knows quite what triggers the horde of insects.  In fact, no-one knows much about cicadas at all, despite their presence on every continent except Antarctica and their impossible to ignore, earsplitting calls.  That long and decidedly boring youth, and the uncertainty about when they’ll re-emerge, makes researching them tricky.  Imagine deciding to study the periodic cicadas of North America and then realising your three years as a PhD student would be over long before the seventeen years the critters spend underground was up?

An ex cicada thanks to the local orb spiders

One theory is that by appearing so infrequently and irregularly cicadas could avoid the predators – bird, bats, all sorts of mammals – keen to feast on the insect bounty.  Very weird recent work from the US suggests that numbers of predating bird species start to drop around twelve years after the last cicada boom.  Could it be that these devious insects are manipulating the beasts far higher up the food chain?

In some ways, despite its wealth of cicadas, Berowra is less interesting for researchers than bits of Sydney not surrounded by national parks.  Australia cities are unusual, it seems, in that they still have cicada species in the heart of suburbia.  Silver princesses and green grocers survive in quite urban areas on the east coast. A local researcher (plants by day, cicadas by night) Dr Nathan Emery has been trying to work out how these species have survived, and whether there are others that can cope with city life. He’s set up the Great Cicada Blitz, a citizen science project crowd-sourcing information about when and where various species of cicadas can be found.

I’ve had a great time over the last month wandering around recording the din in our neighbourhood and trying without a lot of success to spot the earbleedingly loud cicadas to add to the Blitz database.  The male cicadas’ strategy to collectively produce a chorus so loud it hurts the ears of birds works on humans too, even those with the advantage of being partially deaf already. Apparently even the males cicadas “switch off” the equivalent of their ears (their tympana) to save their own hearing.

Thanks to helpful tips from the experts as they confirm my dodgy IDs, I’m slowly learning how to identify the common species around these parts.  Nathan Emery’s nifty little book A Photo Guide to the Common Cicadas of the Sydney Region has been really handy too. It has a lovely introduction from (and is dedicated to) Dr Emery’s scientist dad who took him and his siblings out cicada spotting as kids – inspiration to continue tormenting my offspring with my nerdy passions.  And who wouldn’t be nerdy about cicadas – an animal whose wings has in-built nanostructures that literally rip bacteria apart…

Graphical abstract

Graphical abstract for Aaron Elbourne, Russell Crawford and Elena Ivanova’s 2017 article “Nano-structured antimicrobial surfaces: From nature to synthetic
analogues” Journal of Colloid and Interface Science 508 603-616.
Shouldn’t EVERYTHING have a graphical abstract?

I should also thank the popularity of the big liquidambar in our front yard with the local insects for the chance to improve my cicada identification skills.  Adult cicadas like to latch onto thin-barked natives, but if push comes to shove they will feed on introduced trees, and liquidambars seem to be a favourite, of our local population of redeyes at least, although I think I’ve also heard calls from local tibouchina and robinia trees, as well as the local Sydney red and blue gums.

Though some cicadas don’t seem to be too fussy about the trees they sup from, you have to worry for the next generation.  In the last year, 15,000 trees – 3% of the tree cover on private land in Hornsby Shire – disappeared, thanks to a rash of tower buildings replacing the old fibros with rambling jungly backyards that used to hug the railway line.  Next gen cicadas popping out about 2023 may find nothing taller than a cordyline to sing from and property developers taking over their traditional role local bloodsucker.

Rough barked tree with cicada shell bettersquare

An exoskeleton clinging to the bark of a tall tree in a local school

I’ve not seen any green grocers or yellow mondays or silver princesses around here.  There are double-drummers in the national parks down the road – they don’t do so well in back gardens, needing an expanse of acreage or bushland to survive.  And so far we’ve heard at least four species around our yard: razorgrinders, black princes, floury bakers and the locally ubiquitous redeyes.

One of a whole bunch of redeyes high up in a Sydney red gum raining down excess tree sap on me

How do I know the red eyes are one of the most common cicadas around these parts, even before I started collecting photos and audio?  Well, that’s the gossip from the local kids.

Cicadas weren’t a feature of my childhood, growing up by the River Murray in South Australia.  But they’re a big part of children’s lives around here.  Even the common names of the local species are courtesy of kids, which explains why they are named after colours or days of the week and not dead white European men as per normal service!

My younger daughter (Anonymous Bob as she wants to be known) gave me the low down on what Berowra kids know about cicadas:

“At school in the cicada season, when the teachers aren’t looking, people climb the trees to try to catch cicadas. They climb the big thick trees because that’s where you find them. The main cicada zone is the little mossy grove next to the library. We treat them like exotic pets and look after them, until they want to be free or they die.

Once, there was a little boy. An older boy gave him a cicada to look after – it was sort of like an adoption. But the little boy decided to let him go so he could be free.

Another time, a bunch of kindies robbed a guy of his cicada. It was freshly caught and it had one leg missing, so he was desperate to protect it. They wanted to call it Princess and he wanted to call it Jeffie. They threw a ball at it while it was clinging to his shirt. It nearly fell off and died. And then the kindies started chasing the guy saying “Princess! Princess!” and then they had an attempted robbery but then a teacher came.”

Jeffrey Princess

“It’s fun to look after the cicadas. They’re kinda cute. Most cicada collectors try to find other species because in our school the redeyes are the most common. We find what they eat and take care of them. The cicadas cling onto your clothes which makes them pretty portable pets.”

Red eye cicada

Red eye at our place

“A while ago we did a thing where we would prank the teacher with cicada shells.   At first it was just a joke and then it became a whole fiesta. It became a game and a compulsory activity. Not that the teacher said it was a compulsory activity, we just made it one.

Originally it was just seven cicada shells a day but it ended up with many many many shells from each person. We gathered cicada shells, and every day we would leave cicada shells around the classroom and she would have to find them.”

Many cicada shells

A very popular grapefruit tree in my neighbour’s garden

“We found the cicada shells everywhere – on plants, on trees, on everything. A few boys were the main gatherers. They did it at school, home, everywhere. They came in with huge plastic bags full: they were the main source of our cicada shells. Sometimes we used white out and sharpies to paint war paint onto the cicada shell to make them unique.

Cicada on key ring

Graphical abstract of cicada exoskeleton on teacher’s key ri

You know how cicada shells have a slit? We slipped that onto the teacher’s key ring and when she found it, she was like “Not again!”. We started making a joke that she was cursed by the demon of cicadas.

At the very end of the year a few of the boys laid the cicada shells in a big love heart on the carpet and put a huge pile of chocolates in the middle and wrote their names on a card with love to the teacher.”

 

Cicada love heart

The love for a teacher expressed in the language of cicadas

Maybe there’s another project to be done on cicadas – a children’s natural history of these rowdy, charismatic insects…

Do you have any stories of childhood exploits with cicadas, in Australia or further afield?  I’d love to hear them!

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

 

Mother-of-millions takes to the waves

Mother of millions cabin close up crop small

You know a weed is a baddie when it will grow without dirt and entirely surrounded by salt water.  The Mother of Dragons inspires GoT fans and baby names but Mother-of-Millions – the stowaway on this attractively decrepit boat moored off Dangar Island in the Hawkesbury – inspires a deep and abiding hatred in bush regenerators, whose job is to try to get rid of weedy garden escapes like this one.

Mother-of-millions – a native of Madagascar – was imported to Australia in the 1950s as a drought tolerant garden plant.  It’s now a restricted invasive plant in Queensland, and can’t be given away, sold or released into the environment.  Here in coastal NSW and the northwest slopes and plains, it’s a declared noxious weed which means landowners (or in this case boat-owners) have a legal requirement to control it.  Like two-thirds of Australia’s noxious weeds, it’s a garden plant that got away.

To add to its charm, mother-of-millions (aka bryophyllum delagoense) is also toxic to humans, pets and livestock.  If animals eat enough of it (5 kilos for an adult cow) they quickly die with heart failure.  If they just have a snack, they’ll get bloody diahorrea, drool saliva, dribble urine and then die of heart failure.  Fortunately cattle are probably safe from this particular crop of bryophyllum.  Unless they are bovines with boats, or like a good swim.

You can pull mother-of-millions out by hand but it is, apparently, a soul destroying job.  The plant can reproduce from tiny seeds, dispersed both by wind and water – I’ve certainly seen colonies in bushland by Berowra Creek.  I hate to think how far and wide the seeds from this estuarine Typhoid Mary have spread.  The seeds remain dormant in the soil for ages, so getting rid of mother-of-millions is not a one-time-only job.  Like its toxic relative bryophyllum pinnate – the evocatively named resurrection plant – little plantlets growing on the leaves can also detach as you’re weeding.   Any tiny fragment of leaf can generate a new infestation.  You can spray it with herbicide, leave it in a black plastic bag to die, or hope for a visit from the (also introduced) South African Citrus Thrip which burrows through the leaves’ waxy coating to lay eggs on its flesh.  But none of this horticultural horror show works as well as setting it on fire.

We all have a biosecurity duty, of course: “any person… who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable”.  And as a responsible gardener and card-carrying greenie, I take those duties seriously.  However I’m not sure the owner of this rickety vessel would embrace the idea of a passing kayaker with a molotov cocktail torching his boat, for all its mother of infestations.

Mother of millions side and rope better cropped small

Flying lawnmowers

There’s aren’t too many workplaces that have their own bird list.  Or offices that you can use as a hide for stalking coy marshbirds.

Buff banded rail with raised leg long and skinny

The elusive Buff Banded Rail of Mars Creek

On the 5 k walk that bookends my train commute from Berowra to Epping, I might see a tree creeper or a figbird, a scrubwren or a fairy wren, a flock of silver-eyes or gerygones or red-browed finches, a eastern rosella or a crew of glossy black-cockatoos.  But the twitching doesn’t end when I arrive, because Macquarie University, where I work, is no mean place for bird watching either.

On occasion I’m asked to explain to prospective “customers” why they should study with us, rather than one of the other fine educational institutions in Sydney.  This kind of sales-pitch is not really my strong point – I’m a teacher, not a real-estate agent.  I find myself fatally drawn to talk, not so much about the passionate lecturers, the interdisciplinary subjects, the fancy technical facilities or even the light-drenched underground train station with tranquil majesty of a church, but mostly about the parrots.  Which, unfortunately, seems to be a niche interest from a teenaged point of view.

Upside down coot horizontal small lighter

So when I found myself surrounded by maybe a hundred birds – magpies, swamp hens and miners mixing it with the galahs and cockies – on my walk home, I wasn’t too surprised.  But the long-billed corellas – their red slashed throats and preposterously dangerous looking beaks – were a new one on me.  For a start they aren’t meant to be in Sydney at all.

According to my bird book and the Michael Morecombe app on my phone, corellas are birds of the inland and the south. But for all that, there are plenty of of them around the cities of the eastern seaboard these days.  So very many in fact that in fact, a corella poisoner has been at work in the Central Coast, killing scores of birds from the flocks that roost in parks on the shores of Lake Macquarie.

Mob of corellas crop smaller

A flock of little corellas at Speers Point on the Central Coast

So how did the corellas get to Sydney and Brisbane anyway?  One idea, as put about by Martyn Robinson from the Australian Museum, is that corellas moved east from the plains during the drought.  But even he agrees that flock numbers have swelled  – along with the wild birds’ English vocabulary – thanks to escapees from cages.  Long-billed corellas in particular are apparently wonderful talkers.

On the face of it, looking at the huge flocks creaking and wheeling over ovals and golfcourses, this sounds like an unlikely idea.  But tracking back through Trove, the wonderful searchable archive of Australian newspapers digitised by the National Library of Australia , it seems that corellas have been going rogue for a long time.

The first reference I find about these birds as pets in New South Wales is a story in 1878 in the Australia Town and Country Journal in about Mr D.E.Dargin bringing them 500 miles overland to join “collected goods of every sort” at the Bathurst Show.  And by 1879 we have the first Sydney corella reported missing:

Lost corella jpeg

It’s a fine thought – these long-lived, clever and social birds breaking out of their cages and joining their wild confederates.  My friend Rose has a beautiful story about a tame galah passed on to her after its previous human died.  She kept it in an aviary outside and most days a flock of wild galahs would land and spend some time on the grass nearby.  One bird in particular would always linger by the caged bird after the rest of the flock departed.

Eventually Rose decided to open the aviary door and let the two love birds fly off together into the sunset.  Galahs can live for up to eighty years, and while they form permanent pair bonds, they will find a new mate if their partner dies.  I like to think of the two of them out there somewhere, enjoying a late-life romance with a side serve of onion weed.

Galahs two heads together corellas background crop

Some people – especially farmers – see corellas as pests. Apparently the long-billed species are a particular blight on ovals and golf courses, thanks to the six inch deep holes they can dig for roots and corms with their spectacular beak.  To be honest this habit endears them to me – there’s a fine radical history to the defacing of golf courses.

Dandelion at MQ extreme closeup

There was obviously good eating to be had last week on Macquarie’s sweeping lawns. I wonder, though, if the very oldest parrots that visit the campus still remember the finer pickings from the time, in the sixties, when it was all market gardens, orchards and chicken farms.

Long beaked corella with grass in front of sign long and skinny amend

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