Fly in, fly out

The first asparagus is up.  The greenflies are sucking the life out of the few broad beans plants that survived the gnashers of the garden’s winter visitors.  The bowerbirds are brutalising the new growth on the liquidambar, in a jaunty colourised style that makes me think we have a flock of Calamity Janes in the canopy.  Spring is here!

But what about the spring birds?  I haven’t heard the first koel of the season, but the channel billed cuckoos have squawked their way into our dreams.  And in the last week, a new rolling trill in the trees: the olive backed orioles have returned.  We rarely see them around here, but according to Michael Moorcroft’s “Birds of Australia” as “common”.  The emergent twitcher in me sighs.

I met a charming French skin specialist once, and asked her why she moved to Sydney.  “We have melanoma in France of course” she said “But really, if you are interested in skin cancer, Australia is the place to be”.

On the other hand, if you long for the sight of that first feathered visitor arriving from a epic transcontinental journey, you’re better off in the Northern hemisphere.  All the ocean in the southern half of the globe, moderating seasonal temperatures; barriers of forest and ocean; a less icy past; uncertain rainfall and an often arid climate; and (somewhat unconvincingly) weirdly, lots of  “V” shaped continents; all reasons I’ve come across to explain why we have so few migrating birds around here (Someille et al 2013; Dingle 2008).

Back home, two thirds of my French oncologist’s local birdlife would be part time residents.  But in Sydney, it’s maybe one in five.  In the outback there are nomads, roaming around trying to find things to eat in an arid landscape, but there are hardly any regular migrants at all.

silver-eye-chestnut-4-crop-larger

Tasmanian silvereye mid-migration, Zosterops lateralis lateralis

What we do have lots of in Australia are “partial migrants”.  Somewhere between a third and a half of bird species have some sedentary individuals while others take off in the colder weather (Chan, 2001).  Most silvereyes, for instance, stay put, but many Tassie birds – chunky numbers with chestnut sides, like the one above – fly across the Bass Strait in winter, possibly island-hopping as they make their way to Victoria, NSW and Queensland.  On my way to work the other day, I was was befuddled by the strange appearance of a crew of migrants – on their way home, perhaps – milling around happily in the company a bunch of plain-brand silvereyes.

Hard working bird lovers have been tagging silvereyes for 30 years (Chan, 2001), so we know what these guys are up to.  But in general, partial migrants are tricky customers – figuring which of the identical birds you see are interstate visitor and which are locals is mostly pretty hard to do.

After reading a bit about research on bird internal navigation systems, I’m starting to think this kind of deviousness may be payback.

One set of experiments involved keeping captive birds and observing what corner of their cage they batter themselves against, driven by migration-restlessness or Zugunruhe (one of those cool German words for which there is no English equivalent).  Researchers messed with the heads of these captive birds, using mirrors to shift the apparent direction of the sun so they could see what new quadrant of their cage they try to escape through.  Other experiments placed caged birds inside a magnetic coil to warp their sense of direction – a research activity truly worth of evil genius from X-Men. Although I do find the thought of a bunch of 1940s songbirds flooding into a planetarium – another early experiment – quite charming (Burton 1992).

 

dawn-moon-best-tight-crop

If you do see a trans-continental migrant in Australia, it will probably be a shorebird.  About 35 beach loving species migrate here (Dingle, 2008).  On a paddle up Mooney Mooney Creek last weekend, I was really happy to see one of them: an eastern curlew, its absurdly long beak mucky after joyously feasting on the mud-flat crabs off Spectacle Island.  Flying from Siberia will take it out of you. Between the bloody photographers, the houseboats and the jet skiiers, it’s not hard to see why these guys are classed as critically endangered around here.

 

 

References

Burton, Robert (1992) Bird Migration, London: Aurum Press

Chan, Ken (2001) “Partial migration in Australian landbirds: a review” Emu, 2001, 101, 281–292

Dingle, Hugh (2008) “Bird migration in the southern hemisphere:
a review comparing continents” Emu  (108), 341-59

Somveille M, Manica A, Butchart SHM, Rodrigues ASL (2013) Mapping Global Diversity Patterns for Migratory Birds. PLoS ONE 8(8): e70907. doi:10.1371/
journal.pone.0070907

Gymnastic bees, virgin fruit and the birds that ate spring

It’s the vernal equinox and out in the garden, the spring flowers are blooming.

It pleases me no end me to think that these little figlets are made up of hundreds of the most secretive of flowers, snuggled inside a hollow-ended stem.

As you can imagine, pollinating figs is an extreme sport.  It’s undertaken by the fig-wasp, which spends much of its 48 hours of life on a suicide mission for fig fertility.  The male wasps hatch, blind and wingless, gnaw their way to one of the as-yet-unborn females, mate with them (eww), chew them an escape tunnel (still not redeeming yourselves, guys) and then die without ever having experienced life outside their flowery prison.  The females emerge and flee, spreading pollen as they go, only to find and squeeze into a second syncope (the fig “fruit” to you and me) through a hole so tiny she rips her wings off in the process.  If she’s lucky she gets to lay her fertilised eggs amongst the miniscule flowers inside and promptly, you guessed it, dies.

It’s really quite a disturbing life-cycle.  It’s with some relief that I can say that my three fig trees – a White Adriatic, a White Genoa and a Brown Turkey – are, like most cultivated figs, sterile mutants.  That sounds bad, but it’s a walk in the park compared to the Gothic splatterfest of the caprifig’s lifecycle.

Figs are one of the very first plants to be cultivated by humans: they have been propagated by us since the Neolithic era, over eleven thousand years ago.  And the outcome of our long association with ficus carica is virgin birth.  Yep, that’s the meaning of parthenocarpy – the way that common cultivated figs produce fruit from female flowers unsullied by any male influence. Since their fruits are sterile, they rely on us to do the hard work of allowing them to reproduce. Bloody skivers.

Actually, humans are quite fond of producing such feckless fruits.  Bananas are a good example.  They’re sterile, thanks to their three sets of chromosones – just like those fast growing “triploid” Pacific Oysters I wrote about in my last post, reproducing thanks to genetically identical “daughters” and “granddaughters” that spring from the plant’s base.  Fig wasps and caprifigs have co-evolved – maybe in some weird cultural way, modern humans with their taste for large, fast growing and seedless fruit and our virgin orchards have done the same.

One way or another, people, myself included, seem to get a perverse kind of pleasure in frustrating plants’ attempts to have babies.

My broccoli, encircled by landcress that deals death to invading insects and safe inside the kids’ superannuated, net-enshrouded trampoline frame – has done really well this year.  Now the weather is warming up, however, it’s taking a real effort to thwart the reproductive desires of my brassicas.  Those tasty flower buds really really want to go the full distance and burst into bloom and it’s taking a serious commitment to broccoli-eating to cut them off at the pass.

I tried, but it’s too late for that for the rocket, the mizuna and the tatsoi – these spring flowers are in bloom, like it or not.

I’m happier about these vernal blooms: magnificently monochrome broad beans in all their line-print glory.

I was a bit worried about my broadies this year, incarcerated as they are beneath the chook dome, my first line of defence against the brush turkeys.  Would the pollinators be able to make it through the 1 cm square lattice of the dome’s aviary wire?  As I noodled around in the garden the other day I had my answer. A European bee hovered indecisively, making careful mental calculations or perhaps looking for a door handle.  Eventually, it seem to sigh and alighted briefly on a wire, adopting what can only be described as a pike position and plunging through for a perfect 10 entry.

It’s a bit early to say, but I think I can see a few tiny bean pods forming so I’m hoping that while I’ve been otherwise occupied we’ve been visited by other elite insect athletes up for the gymnastic challenge.

The local birds seem to be almost as ambivalent about the signs of spring as I am about my brassicas going to seed. The bowerbirds are doing their valiant best to rip all the buds off the liquidambar and the little wattlebirds have been paying excessive attention to the flowers on the chinese lantern.  They’re either defending them from insect attack or eating them – I’m not quite sure which.

I don’t think these red wattlebirds would be capable of doing any damage to the heavy duty flower of a gymea lily, even mob handed.  These monster blossoms are bird pollinated – the red colour scheme is a dead giveaway apparently.  I guess this is the honey eater equivalent of an all-you-can-eat buffet.  Since you can roast and eat the roots and the young flower spikes it could even be supersized bush tucker for us humans too.

Enjoy the equinox: may all your spring flowers be excellent eating!

Going cuckoo

You’re suddenly awake.  It’s very very early in the morning.  There’s an loud, insistent two-note call right outside your bedroom window.  It goes on and on and on, each time inching up in pitch, getting more and more desperate until it’s pretty much a hysterical squeak.  Just when you think the bird’s going to start outright screaming or explode, abruptly it stops.  You settle down in bed.  And then it starts again.

Or it’s the middle of the night.  Somewhere in the darkness, there seems to be a huge, angry and deeply confused seagull, belligerently squawking in disgruntlement and disgust: “Where the hell’s the beach??! And where are my chips!!!?”

It’s spring and they’re back.  Koels with their plaintively annoying round-the-clock cries, and channel billed cuckoos, raging at midnight (and during the day as well).

I heard my first koel, bang on time, the day after the vernal equinox; a raucous channel billed cuckoo interrupted one of my classes a few days before.  They’ve flown in from the north in time for the breeding season.  Sydney: it’s officially spring.

Despite their loud voices I have only ever eyeballed koels a couple of times.  On both occasions it was a whining juvenile that got my attention.  Down the bottom of the garden a year or two, I watched a great galumphing teenager begging for takeaway from a  motherly if diminutive wattlebird. We’re still working on installing LBB (little brown bird) habitat around here.  In the meantime wattlebirds rule the roost, along with magpies, kookaburras, rainbow lorikeets, cockies, brush turkeys – the usual self-confident generalists and anthropophiles (is that even a word?).  Which suits the koels fine, since red wattlebirds seem to make great parents.

Channel billed cuckoos prefer currawongs and occasionally magpies as babysitters, and since a mob of maggies has been hanging out at our place over the winter, I wonder if we might get an in-situ “fig hawks” or two as well.  My dad spotted a mega-cuckoo at the top of the drive last weekend, so it just might happen. Surprisingly, considering its deafening cries and outlandish hornbird-esque appearance,  no-one knows much about what the channel billed cuckoos get up to in their spare time.   So, go, backyard birdwatchers, go! Do that citizen science thing!

For all the mystery, it seems these guys, like the brown cuckoo doves, cooing outside the kitchen window in a more decorous and paradigmatically cuckooish way, are some of the winners of the anthropocene.  They like us and our tasty fruit-bearing trees.  And they favour the parenting style of the other birds that enjoy the buffet. Currawongs have come down from the mountains in the last forty years to snack on Sydney’s privet and lantana, and the visiting cuckoos are pretty happy about it.

Reflecting on how much these birds seem to enjoy our company, I’m tempted by a “humans-as-brood-parasites” line of thinking.  Begging for food from our animal compatriots, all the while chucking their babies out of the nest. Terminating the blood lines of the things that came before us in a flash and replacing them with more and more of our own offspring.  Bigger, noisier and more devious than the critters that feed us and house us.

But let’s not go there.  It’s a nasty thought, and whatever we might say about humans, cuckoos just aren’t that bad.

Bowerbirds: snacking for solar gain

Before the fall

Before the fall: it’s always sunnier on the other side of the fence

The gang’s back.  Loads of satin bowerbirds in the garden at the moment.  I’ve seen a couple of mature males, with their glossy blue-black feathers and gorgeous indigo eyes, but most of the robotic whistles, clicks, churrs and cracks in the trees seem to be the “greens” – juvenile males and females, hanging out in a pack.

I’ve heard grim stories about the antics of bowerbirds in the veggie garden.  Apparently they like to lull the backyard grower into a false sense of security and then swoop in and devastate your greens.  But I’m feeling kind of relaxed on that front.  After the brush turkeys exhumed my long awaited Hass avocado treelet, and my big girls, the young-bloods, the prodigious egg-layers, started lounging around under the baby banana trees, making eyes at my kale and chomping on every “poisonous” rhubarb leaf the moment it unfurled, I’ve decided to go totally Christo.  Every seed, every seedling, every newly planted tuber has its own little  blanket of horticultural fleece.  Anything growing that’s remotely likely to appeal to the poultry palate is swathed in netting.

The one upside of the chooks’ blithe disregard of the garden fence is the complete and total elimination of trad from the veggie patch.  Three months ago our spindly raspberry canes and brave little Nightingale persimmon were drowning in a lush wash of juicy stems and emerald leaves, even as the ground slowly dehydrated around them. But now – nada.  A few stems scattered around, waiting to reroot after the rain but not a leaf to be seen.  It’s all very satisfying.

So it’s not all bad when your flock take to the greenery.  The bowerbirds haven’t got a chance of getting my broadbeans.  But with their leaf-picking ways, they are doing sterling work for the environment.

Brushturkey in liquidambar

Brush turkey roosting in our poor denuded liquidambar

Their latest hang-out is the neighbour’s liquidambar tree – gorgeous and looming, throwing a great long shadow across our ice-box house all autumn. Basking in the sunshine on the other side of the fence, it steadfastly refuses to shed its leaves, months and months after our poor overhung specimen has shivered and shaken off its own.  And then, when the last ruby shreds are about to be blown from its branches, and the winter sun finally promises to warm our August days, the bloody thing starts growing leaves again!

But never fear, Super Satin Bowerbird is here!  I can’t prove definitively that their main objective was improving our passive solar gain but after closely studying these photographs for insights into bowerbird psychology and culinary habits, it certainly looks like it.