R2D2 in black and white

I’ve been spending a lot of time with magpies lately.  “Model magpies” as my nine year old aptly described these two who spent the day  posing in the Japanese maple and prancing around the back deck.  Oddly enough, the companionship steps up in intensity whenever I stop typing for a snack.

This gang of youngbloods don’t spend all their time begging for food and doing catalogue shoots, though.  There’s also the occasional training session for the Olympic synchronised vogueing competition.

And, of course, plenty of carolling.  The juveniles spent a lot of time last week singing for their supper, until one of the grown-ups got jack of the whole thing and flew down to show them how it was done.

But not before the youngsters did their party trick.  In amongst all the mellifluous warbling, my ear caught some distinct moments of robotic squeaking and clacking. The magpies were doing a bowerbird impression.

Apparently Australian birds are uncommonly good at mimicry.  Lyrebirds are famous for it, but all sorts of implausible suspects have a line in impressions as well: magpies, mistletoe birds, silver eyes. Apparently the minute brown thornbill has been recorded mimicking a pied currawong – a bird forty times its size.

Why do birds mimics the songs of others?  Pretending to be something bigger and tougher for self defense purposes seems to be one motive.  Bowerbirds have been observed doing raven impressions while being mobbed by a colony of those rather nasty bell-miners, for instance.

Another seems to be showing off to make yourself look good to potential mates.  Researchers have found that male bowerbirds that can only manage a one or two rubbish impressions (singing “like a kookaburra with bronchitis”, as the researcher cruelly remarked) have less mating success than those who can effortlessly produce a good five.

The most hilarious explanation I’ve read for bird mimicry is to chill out sexual partners.  Researchers reckon that R2D2 style squeaks and clicks that satin bowerbirds make while courting can freak out their mates:

“by interspersing melodic mimetic laughing kookaburra and Lewin’s honeyeater calls between episodes of harsh mechanical calls, males may calm females and improve the likelihood of that females will stay for additional courtship and copulation” (Borgia and Keaghy, 2015)

The idea that a sudden explosion of kookaburra calls would mellow you out and get you in the mood gives me a good picture of why certain male bowerbirds (and possibly particular male ornithologists) might be unlucky in love.

While not as famous as lyrebirds, bowerbirds do some pretty amazing impressions, not just of individual sounds but of whole acoustic scenes.  How’s this, observed from a toothed bowerbird?

A male started with the sounds of a group of people talking as they moved through the forest with their machetes cutting bushes and dogs barking, and continued with the sounds of machetes being used to fell a tree, complete with the rattle of shaking leaves after each blow and eventually the sound of the tree falling and hitting the ground with a crash (Borgia and Keaghy, 2015, 97)

The humble magpie doesn’t do badly either.  They’ve been recorded copying 21 different species of bird, as well as the sound of horses, dogs, cats and humans.  Magpies, it appears, only imitate critters that share their territory, not just the blow-ins and passers by, so it makes sense that our youngsters copy the satin bowerbirds that seem so spend much of the year in the garden, eviscerating my beans and kiwifruit vines and making free with my broken pegs.

I’ve got a whole new agenda in the backyard now.  There’s those in-flagrante males doing kookaburra impressions to listen out for.  As yet, I haven’t found any references to magpie calls appearing in the satin bowerbird repertoire.  Maybe this will be my contribution to science.  Better still, maybe I’ll catch a bowerbird in the act of ripping off a magpie doing a remix of another bowerbird.  Or the other way round.

Additional references

Borgia, G. and Keaghy, J. (2015) “Cognitively driven cooption and the evolution of sexual displays in bowerbirds”in Irschick, D., Briffa, M and Podos, J. (eds) Animal Signalling and Function: an integrative approach, Wiley Blackwell

Kaplan, Gisela (2015) Bird Minds, CSIRO Publishing

 

A flash of gold and a stash of blue

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Season of mists and mellow tinnies: the Hawkesbury in fall

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

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

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

Yellow tail and autumn leaves horizontal

Fly by from a yellow tailed black cockatoo

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

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

 

More autumnal reflections from our backyard:

Let them eat light!

Autumn in terminal decline?

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Backyard gold

Blood on the mulberries

This means war!  Or at least a humanitarian mission with military elements.

Just when you’ve been lulled into a false sense of security by their generous assistance with your passive solar, suddenly the bowerbirds turn against you.   One minute they’re giving the liquidambar a light trim, the next they’ve descended on your mulberry tree and stripped it bare.

Mulberries are perfect backyard trees.  They’re easy to grow, fruit without chilly weather, and produce berries in spring before the fruitfly really get into gear.  Kids love to eat them: the Halloween themed blood-stained hands afterwards are a bonus.  You can feed them to silkworms which sorts out any number of school projects (and if you’re that kind of person you can weave your own scarves or caftans).  Chooks happily clean up the spoil.  And you never ever see mulberries in the shops – when they’re ripe they’re so soft and juicy they’re unshippable.  You have to eat them warm, straight off the tree.

And if that’s not enough, they also make a great spot for a diamond python’s mid-morning nap.

mulberry bush and snakey

There’s not much you can do wrong with mulberries, or so they say.  You’ve gotta love trees about which it can honestly be said: “you cannot kill them”.  You have to prune them for new growth and berries, but hacking randomly does seem to more or less work, though the outcome might be described less as “a classic open-centred vase shape” and more as “an ugly mess”.

The only bit of advice that people regularly give about mulberry trees is to avoid planting them near paths “to avoid stains”.  Given the chaotic state of our garden, I smiled smugly at this.  And then planted mine right next to the washing line.  Oops.

I know, I know, my Hick’s Fancy should have been netted against the birds (given that they can be weedy, this is probably a good idea for ecological as well as harvest-maximising reasons).  But the bowerbirds haven’t stopped at the mulberry.  They’ve also had a good go at the grapes up the granny flat wall and the kiwifruit vines on the “solar pergola”.  Exclusion netting is all very well but short of getting a great big net dropped from a helicopter to drape over the whole house and yard, there’s only so much you can do.  Thinking about it, that actually sounds like a lot of fun.  All I need is some air support.