The one-eyed butcherbird

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We had an unusual visitor this weekend – a cocky grey butcherbird, turning up first in the branches of the Japanese maple that reaches up to our back deck, and then hopping boldly onto the balustrade.

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Our butcherbird showing off his hooked beak

Butcherbirds are just the kind of generalists – like fellow “corvoids”, magpies and currawongs – that do really well in urban areas.  But we’re rarely had them turn up at our place before.

And this lovely lad (or lass – they look too similar for an amateur like me to distinguish) was notable in another way, too – it had only one fully functioning eye.

Looking side on you could see a glimmer of a right eyeball, but it was sunk back into the feathers of the head – on a front view only his inquiring left eye was visible.

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Our one-eyed butcherbird

The wounded eye seemed to have healed long ago – this guy was distinctly perky and healthy looking, if a little edgy.  And this was an adult bird – no sign of the brown and buff colours of a juvenile (like this one spotted at Narrabeen Lake a few years ago).  So whether it had been injured as a chick or as an adult, it seems to have been getting along okay for quite some time.

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Juvenile grey butcherbird

In the past, animal rescue organisations assumed that birds with serious injuries to an eye wouldn’t make it if they were released from captivity.  Usually birds found wounded in this way were euthanised.  But in Germany and the US, researchers and birdwatchers have reported hunting birds like owls and eagles surviving for years in the wild – and even successfully breeding and raising chicks – with only one functional eye.

On a first glance, it seems obvious that binocular vision would be important for judging distances when flying.  An early twentieth century ornithologist proposed that “a bird is a wing guided by an eye” but it seems there’s a lot more to eyesight in birds than navigating through the air.

Researchers think that binocular vision is more about being able to see what you’re doing with your beak than getting around on the wing. Birds that have to do tricky things with their bills – cormorants making sure the fins of the fish they’ve just caught are in the right position to slide nicely down their throats, for instance – need to see what they’re doing.  Having your eyes at the front of your head means you’re less likely to spot a predator from behind, but it’s worth it for the tucker.

It was interesting to watch our visitor managing life with a limited visual field.  He could certainly fly, and RB saw him successfully catch something that was scuttling around on the deck.  That said, when we (naughtily) fed him a few pieces of meat, he seemed to struggle a little to get a handle on it.

He was also pretty twitchy, reacting to every sound, looking regularly over his shoulder so he could keep tabs on his surroundings with his good left eye.  Butcherbirds usually dive down on prey from above, and as he looked out for tasty treats below, he kept his head cocked to maximise his vision.  As a someone with only one “good” ear, I recognise the advantages of that head tilt!

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Our one-eyed bird keeping an tabs on surroundings with his one good eye

Our visitor also seemed to understand the possibilities of humans as a resource.  At one point he flew right up to where I was sitting by the balustrade, looked me in the face and “spoke” to me in a mildly demanding way familiar to me from my teenaged childen.  Later on, I went inside, leaving the sliding door was open, just a bit. The butcherbird hopped up to the door,  and after a few moments of hesitation, continued straight through into the house.

Butcherbirds are smart and excellent problem solvers.  They’re also creative, as my colleague, the violinist and composer Hollis Taylor found, when she started analysing their marvellous improvisational music making.  Was our butcherbird visitor just curious, and yearning to see our interior decor?  No matter how clever these guys are, that seems unlikely.

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I suspect that this guy was looking for friends.  Perhaps some local folks who regularly fed him – maybe in a room with a sliding door, just off a deck?  Did his human buddies take care of him after his eye was injured?  I don’t know but I can say for sure he expected good things from us, and our kind.

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Grey butcherbird expecting good things from humans

References

Brown, Matthews (2016) Clever crows: Investigating behaviour and learning in wild
Torresian crows (Corvus orru) and related Cracticids in a suburban environment, Doctoral thesis, Griffith University.

Hegemann, A, Hegemann, ED, Krone, O. (2007) “Successful rehabilitation and release with subsequently brood of a one-eyed Eagle Owl (Bubo bubo)” Berliner und Münchener tierärztliche Wochenschrift 120(5-6):1

Martin, Graham (2017) “What drives bird vision? Bill control and predator detection overshadow flight” Frontiers in Neuroscience 11

Tyrrell,Luke and Fernandez-Jericic, Esteban (2017) “Avian binocular vision: It’s not just about what birds can see, its also about what they can’t” PLOS One, Mar 29.

Thinking like a bird

One of the things I love about my regular walk to the the train station is the chance to check out the critters’ daily routines while I’m in the midst of mine.  I’m an everyday intruder, just passing through.  Through the carpark behind the panel beaters’ shed where the glossy black cockatoos do their acrobatics.   Over the slimy patch on the footpath that used to lure eastern waterdragons out to play chicken in the traffic (I stress “used to”. Sad face). Past the carefully tended brush turkey mound in the scrub by the library and round the the blind corner where butcherbirds find their roadkill.  So far I’ve never seen them pecking at the flattened remains of kids on skateboards but I worry.

I was trudging home a few months ago, when there was a kerfuffle in the shrubbery that even the most self-absorbed commuter couldn’t ignore. An aggravated bird was repeatedly hurling herself at an invisible enemy, and making a tremendous din.  I spotted a tail sliding behind the trunk of a halfway up a tree – was it a goanna? a snake?  No, a brush-tailed possum, having a late afternoon snack in a grey butcherbird’s nest. Mum was willing to fight for her eggs to her last breath.  I don’t have any pictures of the stramash, unfortunately, despite roaming around Berowra most days like some bumbling stalker, a chunky camera swinging around my neck.

However, I feel a bit less sheepish about my amateur-hour suburban birdwatching – and a little less clueless about butcherbirds – after  reading Gisela Kaplan’s fascinating book Bird Minds (CSIRO, 2015) this week.

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Grey butcherbird makes a rare appearance in the backyard

Bird Minds considers most aspects of avian cognition – social learning, mimicry, tool use, play, abstract thought and emotion  – with a particular focus on the locals.  This, as Kaplan points out, is no mean feat.  Aussie natives are under-discussed in the world of scholarly ornithology, it seems.  She tells (with secret delight, I reckon) how the international community were forced to reluctantly accept that songbirds evolved in the part of Gondwanaland that came to be Australia, overturning 200 years of northern hemisphere prejudice.  The oldest songbird fossil ever found came from here, and recently the discovery of heron footprints from the Cretaceous Era in southern Victoria showed that birds and those other, non-avian dinosaurs cohabited this part of the world, at least, for millions of years.

So, as well as summarising the work of researchers from around the globe, to fill the gap in the published research on Australian natives, Kaplan draws on anecdotes from bird watchers (like the amazing tales of fire-starting black kites that have done the rounds in the papers lately) and her own experience of studying, observing and hand-rearing birds over the decades.  My particular favourite is her story of the adopted 75 year old galah who liked to summon all four household dogs by name in a passable impression of Kaplan’s voice just for the fun of bossing them around.  Every week.  It’s this kind of jolly jape that keeps a bird young.

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Pair of galahs

Butcherbirds are just the type of birds that Kaplan is interested in, although her own research for the last 25 years has been on another member of the Artamidae family, the Australian magpie.  Currawongs, butcherbirds and magpies, like many other Australian natives, don’t fit a northern hemisphere perspective on avian lives.  Grey butcherbirds are wonderful mellifluous singers, for example (though their tunes are less feted than the improvisational outpourings of the pied butcherbird).  But their carolling doesn’t fit the familiar songbird story.

Kaplan points out, for instance, that while northern hemisphere songbirds are most vocal during the breeding season, the Australian bush is often quietest at that time.  Amongst the much studied birds of high latitudes, males sing as part of a courting display.  In comparison, she observes, “Australian species often seem rather ‘egalitarian’ “.  For many Aussie birds, including butcherbirds “there is often no difference in the song between male and female, no marked difference in plumage or size, brooding and feeding of youngsters and defence” (Kaplan 2015 114).  I have to confess, this whole line of argument really appeals to me.

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Magpie in spring

I also get sneaky pleasure at Kaplan’s observations about the cleverness of Australian birds.  Smarts, she suggests, are one strategy for coping with harsh environments and unreliable climatic conditions.  The humble budgie, a desert dweller, for instance, has one of the largest bird brains for its size, along with Cape York’s palm cockatoo, a formidable tool user.  These clever cockies select, shape and stash particularly excellent sticks, some to use as percussion instruments and others to improve nest-hole drainage.  Behavioural flexibility is a sign of sophisticated thinking: I guess musician cum plumber fits that bill quite nicely.  Birds like this, Kaplan thinks, playful, inquisitive and social, fill the ecological niche of monkeys in an Antipodean environment.

Australian birds often live much longer lives than their northern hemisphere equivalents. Permanent pair bonding means that galahs, for instance, or sulphur crested cockatoos may end up in a 60 year partnership.  Kaplan suggests that these long-term pairings require social nous and a sophisticated communication repertoire.  Forget relationship counselling, it could be time to take advice from the local cockies!

Young Australian birds are also likely to spend a long time hanging around with their parents learning the ropes – an extra year for grey butcherbirds, as much as four for white-winged choughs. Which explains the whiny teenagers I’ve been hearing everywhere lately.

It’s hilarious watching great hulking juvenile wattlebirds, indistinguishable from adults to my untrained eye, sitting in the Japanese maple tree out back, calling plaintively and endlessly for parental attention until someone hops up and gives them a lerp.  And last week on the way home, as I passed Butcherbird Corner, I heard the sounds of a youngster calling out that all-too-familiar refrain: “Mum! Mum! Mum! Mum! Mum! Mum!”.  It drives me mad when my kids do it, but on this occasion, pester-power put a smile on my face.  The lumbering youngster was a survivor of the Possum Bloodbath of 2015, demanding quality time (and a take-away) from its weary parent.

The youngbloods may hang around with mum and dad for ages, but they do get off the couch and help with the housework.  Raising your chicks with the help of older siblings and even unrelated adults – “cooperative breeding” – is surprisingly common in Australia, in comparison to elsewhere. If refraining from tearing your life-partner limb from limb with your own beak during the course of 60 years together is a challenge to a bird’s emotional control, how much more so is long-term living with the extended family?

This is an idea that Kaplan toys with throughout the book – that “negotiated living” might  “require… changes in powers of perception: a watchful eye, powers of observation and careful scrutiny of others… watching others means awareness of others and such habits can change from behaviour reading into mind reading” (Kaplan 2015 122).  Complex social lives go along with complex minds.

I rather enjoyed the sly dig at northern hemisphere birds (they sound nice, but could well be dim) that runs alongside Kaplan’s argument for the evolutionary value of cooperation.

in the competitive mode, learning (in males) is for a well-rehearsed performance: an Eistedfodd of dance or song. In the cooperative model, learning is for communication (Kaplan 2015 119)

Old leftie that I am, I can’t help liking the idea that cooperation, “egalitarianism” of the sexes and general smarts go along together.

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Long billed corellas giving me a funny look

I can’t vouch for the rigor of Kaplan’s science, but I loved reading her stories of the cleverness of Australian birds – their “versatility, resourcefulness, complex social and individual problem solving abilities” (Kaplan, 2015, 193).  Reading Bird Minds has given me plenty to look out for as I make my workaday way through the suburban territory we share.