Welcome back, beautiful stranger

Sparrowhawk square crop old

It shows a certain lack of character and imagination to be keen on raptors, but I can’t help it.  I love them anyway.  Even the whistling kites and white-bellied sea eagles I clock every single weekend out in my boat on the Hawkesbury give me enough of a thrill to  clog up my computer’s hard drive with a thousand pictures of them in every conceivable posture and mood.

So two years ago, when I caught this beauty in my backyard, I was beside myself with excitement.  It’s a collared sparrowhawk, one of three species of Acciper found in Australia, along with the very similar brown goshawk and the hauntingly beautiful grey goshawk.  So beautiful that on my one and only encounter with one (whilst pegging out the washing) my camera fainted and so in its barely conscious state was only capable of producing a groggy quasi-mystical image of the world’s only pure white raptor.

I know our beautiful visitor in 2015 was a sparrowhawk and not the very similar looking brown goshawk, having been schooled on the key differences.  Brown goshawks are slightly grumpier and more threatening looking, with a beetle brow and chunkier legs.  Both species, it is said, waggle their tail on landing, but the sparrowhawk does it a tiny bit more rapidly.  As my brother, a much more expert bird watcher than I am, points out, this has to be the most arcane and pointless advice for distinguishing two very similar looking birds.  “Sorry lads, the video of your tail waggling was slightly out of focus.  Can you just circle round and land side by side on that branch again?”

Collared sparrowhawks also have another feature – the absurdly long middle toe of the collared sparrowhawk, used to grip its prey while it systematically plucks them (starting at the vent) and then devours them.  It’s moments like these you’re grateful not to be a sparrow or a silvereye, isn’t it?

But is that enough to tell the difference between a goshawk and a sparrowhawk?  Both apparently have these long middle toes – the sparrowhawks’ toes are just longer and more delicate.

There are other differences too.  Goshawks have a rounded tail, and a smaller eye.  So is it welcome back stranger… or good to see you, lifer?

Both the collared sparrowhawk and the brown goshawk are widespread through their range in Australia and New Guinea – they can be found in arid areas as well as woodlands and suburbia.  They are one of the few raptors that will perch and hunt in gardens, as I saw today.  The fact that they’re partial to a snack on introduced birds like sparrows, starlings and newly hatched chickens (gulp!) may be one reason why they’re considered “of least concern” to people who worry about the current mass extinction event.

But still, they’re not exactly common. Numbers declined from the 1940s through to the 1980s thanks to DDT, although the effect of this insecticide – thinning the shells of eggs – seems to have been less dramatic for them than peregrines and some other raptors.  Loss of habitat for the small birds that sparrowhawks like to eat and competition from pied currawongs that will (somewhat implausibly to my mind) attack both adults and chicks are other threats.

It’s been a long couple of years since that last wonderful visit.

But over the last few days there’s been a new sound from the decrepit pine trees that stand (or should I say lean) between our place and our neighbours’.  At first I thought it was a whiny juvenile wattlebird begging for a feed – the call was a kind of feeble high pitched kik-kik-kik-kik.  And then I saw a creamy coloured bird with wide striped wings and a blunt head, superficially like the “green” satin bowerbirds that hang around here all year round scrounging off my chilli bushes and demolishing my bean plants.

But there’s something distinct and decisive about the way raptors fly.  I eventually got a good look as the bird chilled out in the trees, waiting to ambush passing little passerines, which they catch on the wing.  I’m really hoping they have a taste for noisy miners.

good sideways distant crop wide

These really are very low-key birds.  “Often lives unnoticed in mature-treed suburban parks and gardens” one ornithology site comments about sparrowhawks… “easily overlooked”.  Having spent quite a bit of today staring slightly hopelessly into the naked branches for an immobile, unconcerned and well camoflaged bird of prey I can confirm this.   “Trusting and approachable“, the Peregrine Trust’s turn of phrase for a collared sparrowhawk, seems like a slightly embarrassing description for a predator.

Sparrowhawk profile crop tighter still

A gorgeous profile on display.  One very chilled out bird.

The grumpy reputation of Brown Goshawk is apparently not just a consequence of their Resting Bitch Face.  They’re also apparently quite aggro around the nest.  True to form, sparrowhawks are said to be calmer.

Perhaps this parental behaviour will be the solution to my ID problem.  There’s a nest made of sticks high in the neighbour’s pine tree, a spot I saw the sparrowhawk returning to several times today.  If there’s anything better than grown up raptors in your backyard, it’s a clutch of baby raptors.

nest rop

Could this be a sparrowhawk nest?

Blood feud in the dawn redwood

male-koel-neck-arched-square

Every year for the last seven years, I’ve heard koels calling, loudly and desperately, right outside my window, day and night, for the three months from the equinox to Christmas.  And for the whole of that time I’ve been trying to get a decent photograph.  A while back, I caught sight of a whopping great juvenile sitting around on a branch of the pine tree, whining for more food from his adoptive mum, a harassed looking red wattlebird. But that’s it.

I know they’re there, skulking in the trees, the males advertising their availability in an increasingly high pitched, eventually hysterical squeak from the cover of the leaves.  And there’s that duet that koel couples, both equally well concealed and well amplified, produce – the male exclaiming “wurru-wurru!” while the female interrupts with a simultaneous “keek keek keek!”.  But where are these potentially ear damaging exchanges coming from?  Who can say.  It’s like trying to locate a pair of shy and slightly drunk ventriloquists.

But that all changed in my backyard yesterday.  I’ve finally got my stash of koel shots.

Why did these cryptic birds let me get close enough to take a million pictures?  I reckon it was because there was a battle on in the branches.   The prospect of scoring, through combat, a romantic enounter with the iridescent, satan-eyed male seem to make the feuding females oblivious to all that clicking and crashing in the undergrowth.

The  sexual proclivities of koels are not well understood (by humans anyway.  You hope koels have a decent grip on it).  Brood parasites are inherently interesting critters, so koels’ interactions with the honeyeater “hosts”, whose nests they visit to lay their eggs, has been studied exhaustively. The changes in their migrating habits as the world warms up have been looked into a bit as well (eg Chambers et al 2014).  But how and with whom they do their coupling is all a bit of a mystery.

You can’t give the ornithologists too much grief about this.  Even the most avid twitcher is going to be a bit dubious about spending the three years of a PhD shinning up trees clinging to a GPS tracking device, in an attempt to pin down the sexual encounters of an intercontinental migrant of no fixed abode.  And that’s not even considering the koel’s antisocial habits: the fact that they are “typically wary and difficult to observe [remaining] in thick foliage, high in trees, calling from concealed positions” (Healy and Healey 2007).

female-koel-peeking-around-leaves-crop

So what did I see (or half see) in our metasequoia tree after breakfast yesterday?

Did I witness a female, already partnered however temporarily with Mr Shiny Feathers, being challenged by a youngblood for access to a mate?  Koel males are apparently “polygynous” – they mate with multiple females.  But those ventriloquist duets suggest some kind of short-term liaisons, since couples that sing together like this, apparently, often have some kind of ongoing arrangement (Maller and Jones, 2001).

Or just two females both keen to hook up with guy who had command of such a fine calling station, my beautiful dawn redwood?

 

The male was staying well out of it, watching cagily from the side lines.  At one point I spotted him passing somethinga nuptial gift of a berry? – to one of the warring females.  I didn’t see if him get anything in return, unlike the lucky Asian koel spotted by this Singapore based bird watcher. But then with bird couplings, blink and you could easily miss it.

koel-eating-a-seed-crop-for-amend

Female koel… with nuptial gift?

 

But if the male bird was playing favours, this was strictly a chick fight.

At first it was a rap battle.

Eventually the two females settled at opposites ends of a branch, studiously ignoring each other, like gunfighters in a Western pacing the far ends of Main Street.  And then it was on, with a flurry of feathers and a fanning of tails.

two-koel-on-branch-flipped-and-cropped

Two female koels about to tussle

 

Such chick fights aren’t as unusual as old-fashioned zoologists might think. Females that live in groups, it seems, often engage in “intense female-female competition over reproduction, dominance rank and other components of social-living” (Rubenstein, 2012, 2250). I’ve seen it with the chickens.  According to the implausibly named Clutton-Brock and Huchard, in a recent article for the Royal Society these fights “peak… during the reproductive season [8183], and … can lead to wounding or death [28,84].”  And fights are not just about access to mates, but about protecting eggs or nesting sites, space or foraging territories (Tobias et al, 2012; Krieg 2016).

Intriguingly, competition between females seems to go along with good looks or “ornamentation”.  Or better still “ornamentation and weaponry”.  And female koels, while not obviously armed to the teeth, surely are beautiful birds; like most ornamental or colourful females both substantial in size and hailing from the tropics (Dale et al 2015).

sideish-female-koel-with-good-view-of-stain-include-square

Hang on, what is that mysterious red stain on that creamy chest?  Was this a battle involving “wounding or even death”?  Was I witnessing an injured female being challenged, in her moment of weakness, by a healthier rival?

In some of my photos it surely looks like it.

Is that a blood stained beak?  Was this a ghoulish outcome of a predator attack followed by a desperate battle for genetic survival?

female-koel-with-red-beak-squareOr is it just mulberry season?

References

Chambers, L E, Beaumont LJ, Hudson IL (2014) “Continental scale analysis of bird migration timing: influences of climate and life history traits” International Journal of Biometeorology 58 (6) 1147-62

Dale, J., Dey, C, Delhey, K, Kempenaers, B, Valcu, M. (2015) “The effects of life history and sexual selection on male and female plumage coloration” Nature Vol 527 pp.367-71

Healy, C and Healey, E (2007) “Diet and Roost-site Fidelity in the Common Koel
Eudynamys scolopacea in Suburban Darwin” Australian Field Ornithology 2007, 24, 184–186

Maller, C J and Jones, D N (2001)”Vocal behaviour of the Common Koel, Eudynamys scolopacea, and implications for mating systems” Emu, 2001, 101, 105–112

Rubenstein, D.R. (2012) “Sexual and social competition: broadening perspectives by defining female roles”  Philosophical Transactions: Biological Sciences, Vol 367 No 1600, 2274-2293

Tobias, J. et al (2012) “The evolution of female ornaments and weaponry: social selection, sexual selection and ecological competition” Philosophical Transactions: Biological Sciences, Vol 367 No 1600, 2274-2293

Krieg, CA, Getty, T. (2016) “Not just for males: females use song against male and female rivls in a temperate zone songbird” Animal Behaviour Vol 113 39-47

 

Gaia drops the ball

Gaia drops the ball

It’s that time of year again – the rainbow lorikeets are delightedly munching at the flower buds of the neighbour’s “instant tree”, the Common Coral Tree, Erythrina x sykesii. How wonderful it would be if this were an example of biological control in action, with the gloriously feathered native bird (native to the east coast anyway, pest in the west) destroying the reproductive system of the equally vividly arrayed noxious weed tree. But no, sadly unlike its hateful and equally tasty cousin the Cockspur Coral Tree, Erythrina crista-galli, which does reproduce by spreading its seed, the Common Coral Tree reproduces vegetatively. A new tree can grow from a branch washed down a creek or even from a fragment that’s been through the chipper. So, visually delightful as the Rainbow Lorikeets are as they dangle like psychedelic blooms on the bare branches, they have no impact at all on the success of this damned tree. Weeds one, self-managing ecosystems nil…