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mccnmatt

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November 2, 2016

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Animal communication, Backyard birds, brood parasites, Native birds, Uncategorized

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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.

Curious male koel

Satanic looking male koel

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?

Male and female koel closeby

Male koel in profile

The male was staying well out of it, watching cagily from the side lines. At one point I spotted him passing something – a 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.

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.

Female koel calling

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 female koels about to tussle

Female koel gearing up for action

Female koel looking pensive

Ruffled feathers after the encounter

Heading into the fight

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 [81–83], 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.

Female koel with unstained chest

Weary and stained looking female koel

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-square Or is it just mulberry season?

Quizzical look for a female koel

Quizzical look from a male koel

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

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mccnmatt

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April 16, 2016

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kayaking, Native birds, Uncategorized, Waste, waterways

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What do you get if you cross a snake with a panda?

The geometric art on the Australasian darter’s back

Things I learned from last weekend’s paddle from Lake Macquarie’s Shingle Splitters’ Point to Dora Creek:

1. When kayaking on the largest permanent salt water lake in the southern hemisphere, always remember fetch. Fetch can defined as the distance of open water over which wave-creating winds blow. Where does the word “fetch” come from, I hear you ask? From the cries of sinking kayakers as they disappear behind the white tops: “Fetch the emergency services!”

(Don’t be deceived by the apparent smoothness of the lake surface here – once the wind picked up I was too busy thinking about staying afloat to take any pictures)

Heading across Lake Macquarie from Shingle Splitters’ Point

2. The lyrics of Kenny Rogers’ immortal song “The Gambler” don’t just apply to card sharks, but also amateur bird photographers. “You never count your money when you’re sitting at the table. There’ll be time enough for counting when the dealing’s done”.

Because the few seconds you spend checking to see if that wildly optimistic over-the-shoulder shot caught the hunting osprey mid-dive, will be ones in which the hungry raptor wheels around and splashes down again, right next to your boat. And flies off before you can get the lens cap off your camera.

Departing osprey

Darter near Brooklyn

Female darter near Marramarra Creek

Male darter by Milson Island

Male Australasian darter at Apple Tree Bay

Male darter at Speers Point

3. While adult Australasian darters are the most sinuously elegant of birds, poetry in snake-like motion, their offspring are actively disturbing.

Juvenile darters near the nest

Closeup of the absurd faces of juvenile darters

What is it about these baby darters? They’re very very fluffy. Like a gorgeous soft baby panda. A delightfully fluffy decapitated panda with the head of a snake. A sweet duo of snake-panda in a nest white-washed with guano. And they didn’t think much of me either.

Juvenile darter expressing themself through the medium of guano

In South America, they’ve found are darters in the fossil record that weighed 17 kilos – more than eight times as heavy as these not-insubstantial characters. Just imagine how unnerving it would be in a kayak under that humungous reptilian chick when it let fly.

There’s no danger of modern darters – anhinga to give them their formal name – vanishing like their massive forebears. Like humans, darters like deep, still water not choked with vegetation, as long as there are overhanging trees to nest and perch on. And they don’t mind introduced fish like carp and perch, so they’re doing better than birds that prefer marshy wetlands or are fussier about their diet.

A few weeks back, my brother and I watched with a fine male hunting from the shore of Lake Macquarie in the golden light of the late afternoon. Even after the bird vanished below, we could follow its progress by the tiny fry that leapt from the water. The sinuous head reappeared moments later, a fish impaled on its beak. It took him a few goes, but finally he managed to flick it into the air and gulp it down.

Male Australasian darter trying his wings by Lake Macquarie

Darter skewering a fish

Darter about to fling a fish in the air

Male Australasian darter with a fish impaled on its beak

I’ve seen plenty of snake birds, as they’re sometimes called, over the last couple of years as I’ve paddled around the lower reaches of the Hawkesbury and the rivers and lagoons along the Central Coast. Familiarity hasn’t dulled my enthusiasm for them – the males geometric abstracts, the females russet in the sun, their elegant necks holding poses as striking and absurd as those of modern dancers. But I’ve never seen the young ones before.

Darters breed erratically, it seems, whenever and wherever conditions are good. They will fly long distances – up to 2000 ks in the non-breeding season – and will nest inland when floodwaters linger. Maybe the stretch of Dora Creek where I saw them is a regular breeding spot. In one fecund tree I saw two empty nests, along with two brim full of snake-pandas and guano. Or perhaps the vacant real estate belonged to other waterbirds, since darters seem to like to nest in company. Down the river, egrets, cormorants and partly-fledged juveniles were hanging out on a branch together, not far from this perturbed looking male with his runaway egg.

Casuarina with four waterbird nests

Male Australasian darter on the nest with a runaway egg

Partly fledged juvenile Australasian darters

Greater egret in a suburban front yard by Dora Creek

One way or another, the younger chicks seem to prefer intimacy to solitude, finding comfort, as they crouched in their absurdly flimsy nest, in the softness of their siblings’ breasts and the predatory encircling of each others’ snakey necks.

Three darter chicks snuggling crop tighter

Juvenile Australasian darters snuggled together in what remains of their nest

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mccnmatt

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April 3, 2016

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Death, kayaking, national parks, Native birds, pollution, Predators, Uncategorized, waterways

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Death and good fortune on Cowan Creek

Since reading the poetic prose of H is for Hawk, Helen MacDonald’s story of how training Mabel the goshawk carried her through wild sadness that followed the death of her beloved father, it’s been all about the raptors around here.

Easter at Speers Point meant ospreys relaxing in the late afternoon sun.

Osprey with eye gleam for crop horizontal

And yesterday, on Cowan Creek, the contractual obligation white bellied sea-eagle.

Juvenile white-bellied sea eagle

“Peach Trees” – or peregrine corner

Sandstone patterns in Yeoman’s Bay

White-faced heron hunting at Yeoman’s BAy

Then, just when I’d resigned myself to a pleasant if uneventful paddle after three hours on the water, there was an explosion of action right off my bow. Two birds in an aerial battle, tumbling and squabbling over a kill. The loser flew off, disgruntled; the death-dealer pulled up in the bright morning sunshine on a branch over the river, and waited for me to get out my camera.

Peregrine falcon in profile with prey

Peregrine staring straight at the camera

Peregrine gripping a dead galah and looking for rivals

A new bird! One I thought I’d never seen on any waterway. A peregrine falcon.

It turns out I had seen these birds before, long ago and far away – a pair tussling with ravens over a ledge to nest on at Malham Cove in Yorkshire. Cliffs (or, if they are hard to find, skyscrapers) are one of the essential requirements of this beautiful raptor. RB reminded me that peregrines used to nest in the ventilation towers of the tunnels under the River Mersey and high up in the Liverpool’s Anglican Cathedral, the enormous red sandstone building I could see from my desk during my decade as a Scouser.

Peregrines may be the most widespread bird in the world, living on every continent except for Antarctica and on many islands (although strangely, considering its status as a bird watching paradise, not New Zealand). Its name is derived from the Latin for “the wanderer” although only five of the nearly twenty subspecies – those breeding in the northern Arctic – really migrate very far.

For all their capacity to adapt to life in the city – eating feral pigeons and nesting in highrises – peregrines are widespread but not really common. Since they mostly prey on smallish birds, themselves often insect eaters, falcons bioaccumulate pollutants. The use of organochlorines in insecticides like DDT devastated their numbers in the second half of the twentieth century. By the 1960s there were no peregrines in the Eastern US and the birds were declared an endangered species. Numbers have bounced back, in Australia and elsewhere, although they are still classed as “rare” here. And recent work in Europe and Canada has observed a new chemical – flame retardants – turning up in the blood stream of peregrine chicks.

Peregrine mid-dinner, beak covered in feathers

Once peregrines find a good nesting site, it’s a keeper. Apparently, a falcon skeleton found at the back of a cliff-top eyrie in Tasmania has been carbon dated at 19,000 years, which makes that spot the oldest known bird’s nest. As I noodled along the northern shore of Cowan Creek, I’d admired the 100 metre high cliffs of Looking Glass Spur, eucalypts halfway up the face finding impossible footholds in the sandstone. I wonder if my falcon and its mate have a scrape there, high above the expanse of the estuary. Peregrines don’t eat fish but hunting grounds by water offer the space for their deadly turn of speed.

I feel less disappointed by my failure to spot the raptor’s stoop or to capture the battle on film after I figured out what I was watching. The fastest animal in the world, dropping on its prey at nearly 400 kilometres an hour. That poor bird clutched in its talons -maybe a galah, the favoured meal of the big-footed Australian “macropus” subspecies – never had a chance.

Peregrine eating a galah

Peregrine falcon’s tongue on display

I watched for twenty minutes, as she plucked and dismembered her meal, unperturbed by the rowdy parade of jet skiiers, cruisers and powerboats. Galah feathers drifted down from her branch, making a delicate trail of death across the bottle green water.

For a few dodgy moments, I thought the gobbets of galah might be joined by flotsam from my shattered craft as Egg was washed perilously close to oystershell sharpened rocks. And, if I had the Bond-style rocket launcher I’ve often fantasised about while ploughing through powerboat wakes on sunny Sunday mornings, fragments of several jet skis.

Peregrine falcon plucking its prey before eating it

Peregrine falcon “macropus” showing off its huge feet

Trail of feathers from the plucked galah

Remnants of the plucked galah

I’m guessing my peregrine was a “she”. Females are a third bigger than the tiercels – the males – but I didn’t have the chutzpah to hurl a swiss army knife up the tree for scale. The two mid-air combatants looked well matched – two males or two females. Definitely not a pair. Since peregrines mate for life – up to 20 years – and often hunt cooperatively, it would seem to be unwise from the point of view of domestic harmony, anyway, to bicker over food.

In fact, Derek Ratcliffe describes exactly what I saw: “feet-grappling over disputed food items” which happens, he says, “at food-territory boundaries during the non-breeding season” (1993, 201). It seems these battles are nearly always between birds of the same sex, although sometimes peregrines fight with other crag-loving birds as well. RB remembers peregrines in springtime at the cliffs at Creagh Dhu, attacking ravens, stooping then zooming straight up to the heights to do it all over again. Sometimes pairs of peregrines will even take on the great golden eagle over rare and valuable real estate.

So maybe there’s more than one pair of peregrines on that beautiful bit of country. Perhaps I’ll see this magic bird again, or her mate, or her rival, until I’m as blase about a peregrine strike as a whistling kite soaring on a thermal. But yesterday, as I took my four hundred photographs while the peregrine peaceably disembowelled its meal, showing the equanimity that makes them the favoured hunting falcon, I felt truly blessed.