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January 21, 2015

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Australian natives, Backyard birds, national parks, natural history, predation

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Backyard bounty

Okay, only metaphorically our backyard… but we got there on foot in less than ninety minutes, and that’s at child pace. In my own garden, the cut the critters take makes me want to weep. It’s a lot more fun watching the surplus of Waratah Bay feeding the locals.

The light blue soldier crab, Mictyris longicarpus

Soldier crabs being rounded up by the kids. Sorry guys.

Light blue soldier crab, coming to get me

A crab-eating goanna was a first for me.

Crab eating goanna looking pretty happy

Goanna digging for crabs

A decent mouthful

Even a bunch of yelling kids couldn’t drive this white-faced heron from a great seafood buffet.

White faced heron hunting at low tide

Heron eating a crab

And this time a squid.

No pics of the circling white-bellied sea eagle, but you’ll be pleased to know, it too caught a fish.

One of Sydney’s “lungs” – Kuring-gai National Park

Mangroves

Epacris longifolia flowering a metre or two from the tideline

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January 6, 2015

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Backyard birds, Geology, national parks, Native animals, natural history, Soil, Weather

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In other sandstone country

Ganguddy – a less misleading name than Dunn’s Swamp

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 by. Layers 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.

Ganguddy

Rock formations

Pagoda

Pagoda lookout

When even sandstone soils can’t absorb the rain

Lakeside sandstone rock formations

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.

Purple swamp hen posing

Purple swamp hen unperturbed by a flotilla of canoes

Purple swamp hen justifying its name by hanging out in a swamp

Purple swamp hens enjoying the puddles after rain

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.

The “house bird”: a male superb blue wren

Crimson rosella waiting impatiently for the drop dunny

The invisible but ubiquitous clamorous reed warbler

Crimson rosella doing unlikely things in the reeds

Little black cormorants watching cricket.

A whiptail wallaby (or “pretty faced” wallaby as fellow kangaroo mafioso prefer to refer to it)

A musk duck. No, it doesn’t have a goitre. It’s meant to look that way.

Eastern water dragon enjoying the attentions of the papperazzi.

Paper daisies.

Thysanotus tuberosus. Another one that’s all over the place.

A teenaged darter hanging out in the local equivalent of a bus stop.

Not just charismatic megafauna. A Botany Bay Weevil.

Lace monitor. Okay, we see these at home too.

Eurasian coots in the mist. Not a good movie title.

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 water dragon – is it a grotty eastern or is it something exotic?

Gambezi fish – mosquito killers or just killers?

Welcome swallows making do with a natural rock outcrop rather than the eves of a railway station or public toilet

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.

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December 31, 2014

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Backyard chickens, compost, Gardening, Geology, History, natural history, Soil

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Happy International Year of Soils!

1967 photo of the cuttings for the freeway at Brooklyn on the Hawkesbury. http://www.ozroads.com.au/NSW/Freeways/F3/ConstructionInfo.htm

I’m not kidding. The UN has declared 2015 the International Year of Soils. And not before time. Everyone should be preoccupied with dirt. I know I am. What is going in down there, under the ground? Are my veggies growing in podzol or mycelium? Hang on, that’s soil profiles in Minecraft, not in Berowra.

The CSIRO’s recently released Soil and Landscape Grid with its 3 dimensional digital soil attribute maps could resolve most Australian gardeners’ soil questions. In case you were wondering how these maps were developed, let me put you out of your misery:

“The spatial modeling was performed using decision trees with piecewise linear models and kriging of residuals. Fifty environmental covariates that represent climate, biota, terrain, and soil and parent material were used in the modeling. Uncertainty was derived using a bootstrap (Monte Carlo-type) approach to derive for each pixel a probability density function (pdf), from which we derived 90% confidence limits”

More kriging of residuals, I say!

Gags aside, this free online resource shows why Australia needs publicly funded science and why sacking researchers in the CSIRO to bankroll Gina Rinehart’s tax breaks is a major error (if you need more persuading, CSIRO scientists also invented WiFi, Aerogard, the permanent pleat, and the word petrichor, which describes the lovely smell of damp earth after rain).

After reading about the rocks in our neck of the woods, however, I’m not sure we are best placed to fully exploit the sophisticated visualising technologies of the Soil and Landscape Grid. The geology around here is pretty danged boring. Other than the odd lens of shale, mostly on the ridge-tops (that is, under roads and houses) it’s Hawkesbury sandstone all the way down, 40 million years and 270 metres of it. Or at least, all the way down to Berowra Creek where there’s an outcrop of more fertile Narrabeen Group of shales, sandstone and clays here and there.

Cutting through sandstone at Mooney Mooney

The humungous cuttings between Berowra and the freeway, showing millions of years of sandstone deposition

More ridiculously huge cuttings on the freeway

Of course, we’re not alone in our preposterously deep beds of sandstone. They’re on display in the Blue Mountains too, though with a few more layers clay and basalt intrusions to break up the tedium.

Huge sandstone cliffs at Wentworth Falls

Layers of clay amidst the sandstone near Wentworth Falls in the Blue Mountains

The humungous quantities of sandstone across a swathe of the Sydney Basin makes my sentimentality about the disappearing rock faces along the new railway cuttings of the Northern Line even more absurd. After reading about the good exposures of Ashfield Shale between Hornsbury and Beecroft, I’ve become a tiny bit obsessed with capturing the freshly exposed slices of Sydney Basin geology as they are revealed by the diggers and before they’re covered with nasty grey concrete. Wordsworth was mortified by the ugliness of railway cuttings slashing their way through the nineteenth century British countryside. Here am I mourning for disappearing railway cuttings, a slice of geological time revealed and then lost again.

Sandstone profile

A slice of sandstone

The sadness of disappearing sandstone

Busy workers covering it all up

Perhaps I should stop grieving the lost glories of the Pennant Hills trackwork and spend more time worrying about what my garden might be doing to the “quartz rich, nutrient poor” soils of Berowra.

My snake beans are kinda sallow – I reckon they need a side serve of well-rotted chicken manure. But even as I contemplate emptying the compost tumbler, I can’t help but fret about where my vegetable garden sits, perched above the national park with its “rich and distinctive assemblage of species that thrive on poor soils” , “60-80 different plant species growing together on an area half the size of an average house block” (Benson, Howell, McDougall, 1996, 24-5). Benson and Howell in their fascinating Taken for Granted: the bushland of Sydney and its suburbs (Kangaroo Press/Royal Botanic Gardens, 1990) mourn:

“much of Hornsby’s rugged sandstone terrain remained undisturbed until after World War III when the increasing availability of the car and improved building technology made steeper, more remote sites available for housing. As a result, bushland on ridge-tops and upper slopes has been totally destroyed, the bush remaining only where it is virtually impossible to built, and along steep gullies which have become drainage lines. Virtually very catchment system includes some suburban development, stormwater run-off from which contains silt and nutrients. These promote weed invasion of sandstone gullies… in newer areas such at Mt Colah and Berowra [the] invasion is beginning, and the consequences appear inevitable” (108)

And that’s us, in our mid-century twentieth century house, teetering on a steep slope in a fold of the hillside you might otherwise call a creek bed. My painstakingly-made hot compost, my organic sugarcane mulch, the poo from my beloved chickens, all building nitrogen, carbon, phosphorus rich earth – garden alchemy. I’m creating an anthroposol – a human made soil – and I’m not entirely sure that’s a good thing.

Yellow podzol? or anthroposol?

Run-off from the garden… sorry, creekbed.

As a homage to the UN’s declaration, I’ve stared in a incomprehending way at a schematic cross-section of Hawkesbury soils, I’ve thought long and hard about our B horizon (by staring even longer at this quite marvellous online introduction to soil classification – thanks again, CSIRO) and I’ve double-checked Minecraft’s definition of “podzolic” with the kids but I’m not sure how far it’s got me.

Maybe this is the chthonic thinking – thinking about the soil and the communities, plant and animal that grow from it – that my friend Kate urges us all to do in her fab blog about the Armidale Community Garden, but it’s not so much grounded me as taken me directly to Hades via the Field of Punishment. This is a special special place of suffering for people who long to understand rocks and dirt but can never remember whether the Devonian comes before or after the Carboniferous, no matter how many times they read David Johnson’s splendid Geology of Australia. And that’s without wrestling with the geopolitics of topsoil loss or the impact of international agribusiness on pesticide residues or the links between soil, country and indigenous chlthonic law…

The only solution to this torment, I feel, is another variant of subterranean thinking: that sense of mindfulness I get sitting in a darkened vehicle with a swag of empty shopping bags, gazing tranquilly at the carefully preserved, sandstone rock exposures in the underground car park of Berowra Coles.

Happy International Year of Soils everyone!

One of Berowra’s USPs – the sandstone rock face in the Berowra Village underground carpark

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November 16, 2014

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anthropocene, Backyard birds, Backyard chickens, History, natural history

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Dinosaurs in the backyard

I’ve been thinking a lot about chickens’ feet lately. Not as as a convenient snack, like the vacuum-packed ones left on a hotel pillow (alongside a packet of condoms) for my parents to enjoy on a recent trip to China. But as a little reminder that chickens are actually dinosaurs.

Abbey’s dinosaur feet

Shyla’s dinosaur foot (do you think she needs moisturiser?)

Treasure’s goth inspired ready-pierced dinosaur feet

The whole avian dinosaur thing has crept up on us over the years, hasn’t it? Children’s encyclopedia facts shifting under middle aged feet, kooky science factoids becoming simple commonsense. The plastic dinosaurs in the kids’ toy basket, made in the 70s, are discredited heritage items now, with not a feather in sight.

When I was a fledgling, Archeopteryx was the only bird-like dinosaur around. But now, it’s just one of many, and not even the earliest (a title currently held by Aurornis xui, which was covered with fine proto-feathers most likely used for insulation and probably couldn’t fly. Naturally, Aurornis is described as “chicken sized“)

I’ve been reading John Pickrell’s Flying Dinosaurs (University of New South Wales, 2014), and he notes that “there is now good evidence that many carnivorous theropod dinosaurs, even fearsome and well known species – such as Allosaurus and Tyrannosaurus – had feathers” (Pickrell, 2014, 84).

Wow! You could knock me over with one of those proto-feathers.

Monitor skin

Snowball’s flightless protofeathers

Dinosaurs did all kinds of bird-like things. Mei Long tucked her head under her elbow to roost for the night (Pickrell, 2014, 48). Fossils show Citipati osmolskae crouching over its eggs like a broody hen (Pickrell, 2014, 179). T.rex seems to have suffered from trichomonosis, a potentially lethal parasite that which rots away the jawbone. Contemporary birds of prey catch it from eating pigeons; T.rex might have got it from gnawing at each others’ faces. (Pickrell, 2014, 60)

I discovered some crazy facts about birds reading this book. For instance, birds have smallest genome of the vertebrates – and bats’ genome is pretty small too. Smaller cells with large relative surface area means better gas exchange and greater efficiency, enabling the high metabolic rate required for flying. Apparently hummingbirds, with the fastest metabolism amongst birds, also have the smallest genome (Pickrell, 2014, 58).

Hard to believe that such tiny tiny changes could make a macro difference, but I guess if you’ve given up teeth and a jawbone to save weight, economising on your genome seems like a mere bagatelle. Inferring genome size from the space of lacunae in bones, researchers have proposed that between 230 and 250 million years ago saurischian dinosaurs – ancestors of the birds – also started to have smaller genomes, while the bones of your triceratops or hadrosaur soldiered on unchanged (Pickrell, 2014, 59).

I was amazed to read that birds don’t breathe like mammals: they have a one-way respiratory system with multiple air sacs that, when inflated, help make them light enough to fly. When birds breathe, the air flows into their their bones! And some dinosaur skeletons reveal the same spongy, pneumatised bones (Pickrell, 2014, 49-50)

“Dinosaurs and birds unquestionably have very very similar ankles. In fact, nobody has an ankle like a dinosaur or a bird” (Phil Currie cited in Pickrell, 2014, 27)

It’s perhaps ironic that chickens’ scaly feet scream “dinosaur” to me, because one of the earliest feathered dinosaurs was Anchiornis huxleii which actually had feathers on its hind legs as well as its forelimbs. In fact, there were loads of early feathered dinosaurs that looked like this. Paleontologists are still trying to work out quite how it could have used these rear legs in flight without dislocating its hips – they were probably for used to enhance aerodynmics or to create drag (Pickrell, 2014, 114).

The startlingly speedy progression of our chicks from tiny bundles of fluff to whopping great layers, made sense of the notion of paedomorphosis, a process in which animals reach sexual maturity at an earlier stage of development

In the brooder

A fledgeling at 2 months old

Four month old Shyla learning new tricks

Shyla fully grown

In comparison to the slow maturing reptiles, birds, like mammals, grow quickly in early on. Interestingly, as they mature, birds’ heads don’t change much in shape; in comparison most dinosaurs’ skulls morphed dramatically, the comparatively large, spherical noggins of babies elongating into the snouts and jaws of adults (Pickrell, 2014, 54). US researchers Bhart-Anjan Bullar, Mark Norell and Timothy Rowe noticed Archeopteryx’s adult skull is rounded just like the babies of other dinosaur species, and concluded that the ancestors of birds maintained juvenile characteristics later in life. This process of paedomorphosis (or neoteny) often goes along with smaller body size. It seems to allow the emergence of a new and unexpected set of features in an organism. Harvard’s Bhart Anjan-Buller observes “These unique characters may allow the exploitation of radically different ecological niches from other similarly sized organisms” (Pickrell, 2014, 56).

And birds have surely filled those ecological niches. There are aroundabout 10,000 living species of birds, far more types of avian dinosaurs than all the non-avian kind that ever lived. “Dinosaurs are now more successful than they’ve ever been, but they all look the same” says Paul Barrett of the Natural History Museum, “With the exception of a few aberrations, they are all bipedal flyers” (Pickrell, 2014, 28).

And let’s not beat around the bush, a really really big percentage of those living dinosaurs are chickens. There’s a global chicken population explosion: there are now about three times as many chickens as there are humans – in the 1960s we were about eekies. And that’s not even considering the ratio of domesticated to wild animals. According to the RSPB, there are maybe 30 times as many domestic chickens as there are the most numerous kind of wild bird, the African dwelling red-billed quelea.

In fact, best not to dwell on this to prevent yourself being plunged into depression about the forthcoming Age of Loneliness, when we humans will mostly likely have few non-human companions. Better get used to the company of rats, cockroaches, and jellyfish. Maybe we’ll have a few bats – to my surprise, there are more species of bats than any other type of mammal except rodents (Pickrell, 2014, 107). And, of course, chickens. Lucky I love my avian dinosaurs.

Andy Ninja the ISA Brown’s knock knees

Treasure the Light Sussex’s dino-feet

(You wouldn’t believe the confused and irritated looks the chickens have given me as I’ve been taking these pictures of their feet. Sorry guys.)

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September 16, 2014

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Death, Garden trees, Gardening, History, natural history, Ornamental gardens, Plants and what I know about them, Seasons

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A fossil in the garden

Gardens are time-capsules. I don’t just mean the odd, poignant occasion when you dig up a bone carefully buried, long ago, by a dog you never met. I mean the fashions in plants that date gardens just as surely as winklepickers, blue eyeshadow or shoulderpads date photographs. As you walk round the suburbs you’ll see jacarandas arching over Californian bungalows, rows of red cordylines hemming eaveless McMansions, 70s brick veneer hidden behind shaggy bottlebrushes and rambling grevilleas. Social history has roots in the backyard.

Our place was built in the late 1950s, and I reckon a few of the bigger trees date from about that time. The largest hibiscus I’ve ever seen, entwined with an ancient honeysuckle as weighty as a strangler fig, reaching up above the roof of our neighbour’s two-story house to catch the light, speaks to me of post-war dreams of expansive America, a Hawaiian fantasy. The liquidambar and the Japanese maple – a yearning for colour in the fall.

A fossil in the garden

Until today, I put the tallest tree in the yard in the same category – I figured it was a swamp cypress, native of the Everglades, happy knee-deep in water (and, with enough water, they do grow knees!). Like a larch, it’s a deciduous conifer, needles turning copper in the autumn, then returning, fresh and feathery green in the spring.

But I was wrong. It’s not an imposing American, though it is a cousin of the great sequoias. It’s Metasequoia glyptostroboides, a dawn redwood: living fossil from the “dawn of time”. It’s the Wollemi Pine of the 1940s. An expedition to a remote village in Szechuan province in 1946 discovered a giant living Metasequoia, a species known from fossil evidence to have existed for 100 million years, thought to have been extinct for at least two million more.

Late autumn sequoia with bird enlarged 2

Metasequoia (“sort of Sequoia”, “Sequoia-ish”) was something of a sensation in the late 1940s. In 1948 Sydney’s Royal Botanical Gardens, along with arboreta all over the world, received seeds and commercial nurseries in Australia began growing them for sale the same year. With seeds both easy to collect and propagate, the dawn redwood, George Seddon says, was a big money spinner and the trees are are now common in parks and gardens all over the world, from the subtropics to Alaska. It’s proudly grown as a street tree in China, though it is critically endangered in its only location in the wild, Metasequoia Valley, not far from the staggeringly huge Three Gorges Dam, a hydro scheme so big filling it slowed the rotation of the earth.

Now of course, I want more lazarus taxa – more trees returned from the dead. Gingko with its maiden-hair leaves, a clear yellow in the fall. Okay, it has fruits that smell of vomit and its edible nut is toxic. Who cares! It’s a dinosaur tree, over a hundred million years old! As is the Wollemi Pine – three clumps of genetically identical trees discovered in a deep, remote canyon in 1994 – weird looking, self-coppicing, lusted over by others in possession of dawn redwood, it seems. Although John Benson of the Royal Botanical Gardens in Sydney advises against hoarding this fossil: “people who put them in their backyard will soon have no backyard” (Seddon, 2005, 100).

A fossil in the garden

My neighbours say every winter they look out their window and think, hearts sinking, that the redwood tree we share has gone and died. Perhaps I should reassure them that it will live for more than a hundred years; that it is Lazarus, come back from the dead; that it has been around for a hundred million years.

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September 13, 2014

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Australian natives, national parks, natural history, Plants and what I know about them, Seasons

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Sprinter (not yet Sprummer)

Clematis aristata (I think!). Or is it clematis glycinoides?

Grevillea sericea

Grevillea buxifolia

Eutaxia obovata and boronia microphyllia (I think!)

Clueless.

Gompholobium virgatum ?

Isopogon anethefolia?

Hakea salicifolia

Glossodia… minor? major? Some kind of

Lysinemas? Is that even a flower?

No idea

Pretty.

Sprinter (not yet sprummer)

Phlebalium? Or something?

Eriostemon australasia (probably)

Tim Entwhistle from the Royal Botanical Gardens suggests we add two seasons to the European standards: starting out with the clunkingly named Sprinter, to describe late winter and early spring when most things seem to burst into flower. He reckons non-Indigenous Australians can’t handle the complexity of the diverse seasons observed by Kooris, Murris, Nunga, Noongar and all the first people of this place.

He’s probably right. The D’harawal calendar – from people south of Port Jackson – says roundabout now is the time of Wiritjiribin – cold and windy. I think I saw Acacia floribunda blooming today, so that fits. But maybe, since its getting warmer, it’s closer to the time of Ngoonungi, the time of the gathering of the flying foxes? “They come in from the north-east, the north, the north-west and the west, and swirl over the Sydney area in a wonderful, sky-dancing display just after sunset”, says the D’harawal calendar on the BOM. No signs here at least, in Dharug and Guringai country, of flying foxes yet.

Let’s face it: I’m clueless. I’ve got no idea about the local wildlife, know nothing of how you might live off the land, can’t even figure out half the Latin names of the flowers in our neck of the woods – Muogamarra, Berowra National Park, Lane Cove.

Ok, I’m cheating. Lane Cove is miles away, but I took some nice pictures there yesterday. And it is (mostly) on Hawkesbury sandstone. And they have a great website for the local flora. Which is important because this is what our plant identification book looks like:

All in all, I think I’m only up to Sprinter.

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September 7, 2014

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Brassicas, Climate change, Edible flowers, Fruit, Greens, natural history, Seasons, Vegetables

Flowers of the Frozen North

Something new in the garden today: hazelnut flowers. Our filberts have been in for about three years, and have produced a few catkins, but I’ve never seen these before. They are very very tiny, though, so maybe they were there last year and I never noticed.

Autumn catkins

Today’s red blossoms

The miniscule red blooms are all on one tree – Ennis, “preferred variety for all markets”, Daleys boldly asserts. Lucky Ennis. “Hall’s Giant” sounds so much more magically productive but it’s mainly a pollinator, dangling those catkins.

Will we get some nuts this year? It seems unlikely. The raspberries, our little Stella cherry, three neglected high-chill apples, the Hayward kiwis, and the hazelnuts, all planted with foolish optimism. Okay, Sydney is subtropical and all these plants require a hundred plus chilling hours … that’s a hundred or maybe a hundred and fifty hours below 7 degrees C while in Sydney’s chilliest month, July, the average minimum is 8.1 degrees…. but we are at 200 metres elevation! maybe we’re in a frost pocket! What about those chilly south-westerlies?

Our mighty leader, Anthony Abbott MP, confidently claims that “climate change is crap” so perhaps we are, as my hirsute medallion-wearing neighbour asserts, heading towards a Snowball Earth scenario: the Pacific Highway to Hornsby will be lined with snowpoles and we will be skating, not taking the ferry, across Berowra Creek. All my eccentric plant selections will be vindicated.

While I’m waiting for a glacier to form in the Sydney Basin, or at the very least for a small crop of hazelnuts, at the bottom of the garden the winter veggies are flowering.

Daikon radish flowers

Daikon

Flowers from above

The daikon is too tough to eat now, but the flowers are lovely and I’m planning to save the seeds. The winter’s chinese greens are also in bloom. The leaves are getting smaller, stringier and slightly bitter though I’ve still been picking them. I’ve got a feeling these may be the mutant offspring of my favourite – red bok choi, an F1 hybrid.

The process of creating the F1s is like something from “Game of Thrones” – ten generations of in-breeding to produce a pure-blooded weaking, that is then matched with an inbred of a different tribe, to produce children with renewed vigour, sharing little with their spindly parents. These muscular cross-breeds are frustratingly incapable of passing on their all-conquering qualities to the next generation (an appropriately Machiavellian outcome that keeps gardeners in the thrall of the Plant Wizards of Monsanto). It’s kind of cool to save the seeds of the F1 hybrids not just to give the multinationals a crinkly mouth but also to see what sport comes up in the next generation. And the next. Who knows, perhaps eventually some robust throwback will thrive in the endless Winter?

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June 19, 2014

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Animal communication, Animal senses, Anthropomorphism, Backyard birds, Backyard chickens, chicken communication, natural history, Predators

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Reflections of a ground predator

What noise does a chicken make?

Some people might go for the classic “cockadoodle dooo!” of an rooster at the crack of dawn.

But many people probably come up with something like this: “Buck buck buck buck” (here’s a video example). That’s what chickens sound like to most of us.

In fact, this is a specific type of chicken alarm call. It means “Ground predator! Watch out!“. In this video, there’s a cat on the prowl. However, this call sounds so familiar to us humans, even those of us who are not chicken obsessives, because we are ground predators. So what we think of as “normal chicken sounds” say less about what chickens normally do, and more about the fact that we’re there, and they’re keeping an eye on us.

Chickens make at more than twenty four different calls (check out some of them on this very interesting video), which are not only referential (“aerial predator” “food” and so on) but are uttered differently depending on who’s listening and what’s going on. In fact, they can be quite machiavellian, deliberately “lying” (for instance, some males make a food call to attract females when there’s no food to be had – though since chickens can recognise and remember up to 100 individuals, this is not a good long term strategy!) They are pretty cunning too. In a recent article in Scientific American K-Lynn Smith and Sarah Zielinski explain how researchers resolved a problem: why do roosters frequently call out a warning about a passing hawk even when this might attract the hawk’s attention and put the rooster himself at risk. They found that roosters are very strategic. For instance, they observe that “a male calls more often if he is safe under a bush and his rival is out in the open, at risk of being picked off by a swooping predator. If the rooster is lucky, he will protect his girl, and another guy will suffer the consequences”.

To sum up, chickens are smarter than humans usually think (if not always nice), and humans… well, humans are ground predators.

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June 14, 2014

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Australian natives, Backyard birds, Climate change, Garden trees, Natives for shade, natural history, Plants and what I know about them, Weeds

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Sweetness and light

On our shady south-west facing hillside (who went house hunting without a compass, then?) there’s just one spot that gets plenty of light year round: not a bad place for some solar panels on the top of a pole. But right in that spot there’s a native tree, sweet pittosporum or pittosporum undulatum. And there’s a healthy specimen of the same species dead to the north of our kitchen windows, right where the winter sun might otherwise beam through.

Hornsby Council is pretty proud of its status as a leafy north shore suburb – “The Bushland Shire” – and dissuades its rate-payers in the strongest of terms from cutting down trees. But not this one. Until 2011, despite its status as a native, gardeners had a licence to kill sweet pittosporum, along with a select few imported nasties – cotoneaster, camphor laurel, privet and coral trees. But now it’s a different story. You can chop down quite a lot in Hornsby these days – pretty much any non-native tree. You can even gaily hack down Australian natives that don’t hail from this part of the Hawkesbury. But put that saw down! Pittosporum is now right there on that not very lengthy list of protected local trees, shrubs, grasses and vines. It’s a dramatic turnaround, from big-league environmental weed to local hero, all in the space of a single year.

A bird snack

Pittosporum is probably the least of our problems here!

The undulating, light blocking leaves of the pittosposum

So what’s going on here? Tim Low’s immensely readable book, “The New Nature: Winners and Losers in Wild Australia” (Viking, 2002), a fat but fascinating volume filled with stories about birds and trees, insects and frogs and their complex inter-relationships with human beings, has a lot to say about weeds and natives, and in fact quite a bit to say about sweet pittosporum. The essential argument of the book is that any quest to preserve untouched wilderness or to maintain nature free from human interference is not just doomed, but essentially ill-conceived.

Human influence has been making plant and animal winners and losers in Australia for many thousands of years, and Low documents not only the way some pragmatic species capitalise on urban environments (think peregrine falcons nesting in high rise buildings) but the way many others rely on continuing human intervention (like firestick farming or stock grazing) to survive. Sydney’s green and golden bell-frog survives at the Brickpits in Homebush, a location described as “one of the most industrially polluted in the Southern Hemisphere” (24) because these frogs are tolerant of high levels of heavy metals, while the frog-killing chytrid fungus is not. Low points out the limitations of the distinction between “native” and “exotic” as a way of gauging the impact of animals and plants on biodiversity, and argues that decisions about what to conserve and how to do it, are in short, very very complicated. Koalas can be forest killers and cows can step into the gap left by extinct megafauna in maintaining diverse grassland. As a greenie and a gardener, I found the anecdotes and ideas in “The New Nature” provoking and intriguing, making me take a good hard look at my weed anxieties and my fantasies of a bird-friendly, local provenance garden.

Hornsby Council’s change of heart about sweet pittosporum illustrates Tim Low’s arguments beautifully. Don Burke, the Australian Native Plants Society of Australia, Grow Me Instead (The Nursery and Garden Industry Association) and the Queensland Government all agree that it’s an invasive weed. “The New Nature” with its ambivalence about such terms calls pittosporum “our worst native weed” (250), “replacing diverse systems with monoculture” (201). While a canopy of eucalypts allows a rich understory, pittosporum shades out nearly everything else (although that nasty garden escape, privet, apparently copes well). Birds enjoy the pittosporum’s orange fruits and disperse its sticky seeds. Not needing fire or light to germinate, and tolerant of richer soils than many other natives, pittosporum is a native to this neck of the woods, flourishing on the shale ridgetops on Hawkesbury sandstone – most of which are now built on. Run off from houses and gardens has enriched the sandstone soils on the slopes and pittosporum has moved on in. According to Low, “If you take eucalypt forest, add fertiliser and water and take out fire, you have a recipe for rainforest. The pittosporum invasion is really a takeover by rainforest” (248).

Pittosporum undulatum has its defenders. Jocelyn Howell from the Royal Botanical Gardens suggests that pittosporum can shade out and outcompete other more troubling weeds (although Tim Low would argue that even invasive weeds like lantana can play their own role as a habitat). Others argue for it in terms of the food supplies it offers and the fact that it *is* a local really. Obviously, Hornsby Council has plumped for this point of view. Most of the advisories suggest that it’s a weed only outside its home range, using provenance to distinguish true locals from native invaders.

But according to Low’s arguments, its home range isn’t the home it once was. His book gives poignant examples of Sydneysiders talking about the impact of pittosporum (“pittos”) in terms of solastalgia, the sense of homesickness you have when you haven’t left home, but your home has changed forever. Orchids and grasses gone, along with the smell of eucalyptus (248). There are no easy answers here: it’s “a hard one”, “one of the most sensitive issues around” (249). Are the eucalypt forests of the Hawkesbury slowly morphing into (monocultural) rainforest? Will the catastrophic fires I expect and dread drive it back?

From a more selfish point of view, it seems like my kitchen windows will remain gloomy and my solar panels a dream, even as my fantasy as a kid growing up in the arid lands of the South Australian mallee, of coming home to a rainforest seems to be coming true…

Posted by

mccnmatt

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May 15, 2014

Posted under

Animal senses, Backyard chickens, natural history, Possums, Recycling

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Twilight of the Chickens

Jeez, chickens go to bed early. I’m outside getting the washing, and ok, it’s heading towards dusk, but not only can I see the location of my smalls, visibility’s so good I can even spot and dodge the brush turkey doings as I go. But the chooks are already tucked up in their palatial quarters, or in the case of Snowball (pictured above), having a nap in an elevated position while waiting to be eaten.

So, twilight is more complicated than you might think, and I’m not talking about the teen vampire series. Apparently it comes in three types. As the sun first sinks, there’s civil twilight. Technically, that’s when the centre of the sun is 6 degrees below the horizon – in good weather you can still see the things around you (say, your knickers on the line, or an inconvenient pile of guano). Then, after about 20 minutes, more (as you get closer to the poles) or less (closer to the equator), you have nautical twilight. The sun is 12 degrees below the horizon now, and if you’re a sailor, you can take a bearing on the stars with the horizon still visible. If you forgot to pick sweet potato greens before sundown, you’re rummaging around in the cupboard for a torch.

After nautical twilight comes astronomical twilight, with the sun 18 degrees below the horizon. To an untutored eye it might appear as if night has finally arrived, but impatient astronomers wanting to check out nebulae will be still pacing up and down waiting for full dark. Of course, you won’t get the full sequence come the summer in Trondheim (civil twilight from sunset to sunrise), Glasgow (nautical twilight for most of the darker hours) or even London (astronomical twilight all night long, even without throwing in the orange glow of light pollution).

I find this orderly taxonomy of darkening moments curiously soothing, an effect only slightly diminished on reading that nerdy acronyms like EENT (end evening nautical twilight) aren’t just used by meteorologists and astronomers to document the passing days and track the movements of the stars, but also in military campaigns to synchronise watches.

But all this is from a human point of view. For chickens, it’s different.

If possums have got pretty dud typical mammalian dichromate vision, chickens are rocking their cones. Not just three sets of cones like us, but five, including one that enables them to see ultraviolet light and a double cone for detecting motion. And “cellular sunglasses”: an oil-drop to filter particular wavelengths of light.

But wait! There’s more! Chickens also have, in essence, a third eye. Okay, not as visible as parietal eyes of Tuataras and other less famous reptiles (and related organs in the eyes of other tetrapods – like the receptor that looks like a little blue pimple between this critter’s eyes).

But still, a pineal gland perched up just under skull that receives enough light to regulate sleep and trigger annual reproductive cycles. Extremely cool. Perhaps too cool for some. While researching this post, I noticed, right underneath a webpage spelling out the multidimensional excellence of chicken vision, an advertisement for eye surgery.”Replace tired and baggy eyes with a younger look!”. Presumably the reader, ruminating dolefully on the superiority of the avian retina and the failings of human sight, is primed for this kind of thing.

But perhaps we humans shouldn’t be so grim about our drab colour vision, our tediously symmetrical pair of eyes. At the very least the time our mammalian ancestors spent cowering in a burrow while the dinosaurs strode the earth gave us respectable night vision. We can revel in our fine array of twilights while the shutters come down with a clang at the end of the day for our long time companions.

Okay, The Twilight of the Chickens may not have the apocalyptic ending of the Ragnarøkkr, the Twilight of the Gods. The rivalry between Treasure and Shyla over who gets the highest perch in the upcycled coop doesn’t have the same Wagnerian grandeur as Odin’s battle to the death with the wolf Fenrir. But pleasingly, even the Norse myths have a place for chooks: the end of days is heralded by the crowing of a crimson rooster, a golden rooster, and a rust red rooster. I must tell Andy Ninja.