Tag Archives: egret

Standard

Posted by

Posted on

October 4, 2015

Posted under

anthropocene, Backyard birds, kayaking, national parks, Native birds, natural history, Waste, waterways

Comments

10 Comments

Encounters with eagles

May I present this week’s sea eagle?

Sea eagle and a view of Budgewoi Lake
Sea eagle retreating to a pole to eat its fish

As yet on my estuarine adventures, I haven’t seen a score of sea-eagles on a single morning (although I can imagine a battalion of them, flying in formation), but an encounter with an eagle has become as much a regular feature of my kayaking expeditions as the ubiquitous white-faced heron. Those cryptic little passerines in the riverside scrub are hard to spot even if you’re not short sighted and half deaf.  So three cheers for the white-bellied sea eagle “large and conspicuous” “easily sighted when… soaring… in search of prey“.  Haliaeetus leucogaster, you are the middle aged canoeist’s friend.

There was the eagle we saw battling it out with a pair of whistling kites over fishing rights on a fabulous family excursion across the Hawkesbury from Brooklyn, across the surf-line and up the Patonga River.  According to Wikipedia, sea eagles harass smaller raptors like kites in hopes of stealing their prey.  Not today, Josephine.  This eagle was bested by the lowly kite, unwilling to relinquish a top notch fishing spot.  I need to listen to my own advice to my students – don’t believe Wikipedia!

Sea eagle about to launch
Sea eagle soaring in for fish
Whistling kite defending its ground
White bellied sea eagle beats a retreat
Whistling kite aka archaeopteryx
Whistling kite coming in for the kill
Whistling kite hunting in Patonga Creek

An eagle even made a guest appearance on a modest little paddle down the end of our street.  This was one mellow raptor, its apparent indifference to poorly coordinated amateur photographers splashing around trying to get a good shot belying its rep as a “shy and easily disturbed species“.  Ruth, my companion on the water that day, had seen a sea eagle, earlier, on the very same bare branch, while bushwalking along the ridge above. Same bird or just a popular perch?

Sea eagle at Berowra Creek
An eagle eye
Casuarina forest on the edge of the salt marsh on Berowra Creek
Berowra Creek in morning mist
Board walk through the saltmarsh near Berowra Creek
Pied cormorant about to be eaten by a shark

Since the rule for my stolen Saturday morning paddles is no more than half an hour in the car, I’ve frequently had this very thought as I spot yet another sea eagle.  Same bird?  Am I being stalked by just one glorious if persistent raptor who’s somehow taken a fancy to my little craft, charmed perhaps by its avian-friendly name?  Or is the Hawkesbury awash with sea eagles?

Even the Department of Environment in its definitive run down on Haliaeetus leucogaster doesn’t seem super sure. Their guesstimate of 500 pairs across the whole country is based on a one for every 40 kilometre of Australian coastline would pretty much mean that all the eagles in my photos are the same dude (or dudette – the females are larger but I find it’s kind of hard to tell if a bird is small or if it’s just far away).

Either way, I’m 100% sure this week’s eagle is a new one, since I saw it at the start of a paddle down Wallarah Creek, seventy ks north of here.  The creek wends its quiet way through bushland past the Wyong North sewage treatment plant to Budgewoi Lake.  What with my burgeoning interest in taking blurry pictures of distant bird-life, it seems I will be spending more and more time hanging around sewage farms – they seem to be the go-to venue for the would-be twitcher.

White-bellied sea eagle struggling with a supersized meal

The Budgewoi eagles seem a bit more coy than the Berowra locals, as you can tell from this dodgy pic on my maxed out zoom.  Or maybe it’s just that this sea-eagle didn’t want to share her supersized snack.

Which, after observing the consequences of fraternisation with humans for other birds I saw on my way up Wallarah Creek, is probably a good thing.

Pied cormorant strangled by a fishing line
Female australasian darter tangled up in fishing line

Up until recently, it was thought that carelessly discarded bait, hooks and line were the big killers of waterbirds, and there have been some efforts made to make sure fisherfolk dispose of their scraps in the rubbish rather than leaving them lying around – not such a big ask really.  Some have even argued for the use of biodegradable line and hooks that will rust away (eventually).

But efforts to get fishermen to clean up their act have had surprisingly little impact on the number of waterbirds being injured or killed by fishing tackle.   In fact, research by academics and wildlife rescue organisations in South Australia and New South Wales suggest that the vast majority of birds that get entangled or hooked – often pelicans, but also plovers, gulls and stilts – get caught up when they are close to people actually fishing.

After my trip up Wallarah Creek I can see why.  As I passed riverfront houses with their landing slips and jetties I saw pelicans lounging on back lawns and an excited egret being thrown small fry by a local.  Even the striated heron, normally shy, flew off in the direction of human habitation, not the other way.  The birds around here are familiar with humans, their tinnies, their by-catch and, unfortunately, their fishing lines.

Greater egret coming in to land
Greater Egret hunting in Budgewoi Lake
Wallarah Creek
Striated heron
Casuarinas in Wallarah Creek
Scary paperbarks
Existential graffiti channelling the thoughts of the strangled cormorant
Standard

Posted by

Posted on

June 28, 2015

Posted under

Backyard birds, estuaries, Native animals, waterways

Comments

7 Comments

Waterbirds of the Wyong River

White faced heron
Adult white faced heron showing lanceolate plumes (absent in juveniles) on the back
White faced heron hunting shrimp
White faced heron with shrimp

Today, further adventures in Quaternary estuarine geology – a paddle along the lower reaches of the Wyong River, where it meets Tuggarah Lake.  With a brief stop at Lake Macquarie to photograph this heron hunting, that makes two young and lovely coastal lagoons in one day.  And both fine places to be a waterbird. After my recent insensitive remarks about coastal lagoons being fed by underwhelming little creeks, I’m a bit surprised we didn’t have any unfortunate upending incidents today.  The mighty Wyong River is forgiving.  And generous with darters.

Female Australasian darter
Male Australasian darter

And egrets, both intermediate and great.  I’ve got a feeling there’s one of each here.  Despite the name, the sure fire way of distinguishing them isn’t size, but a dark line that runs from the base of the beak beneath the eye.  The great egret’s commissural line runs behind its eye, the intermediate’s stops short just below.  But I still think you’re great, mate, despite your middle-of-the-road name and your meagre eye liner.

Intermediate egret
Great egret. I think!
Looking east on the Wyong River
Closeup of an intermediate egret looking a bit grumpy

On the bank amongst the ducks, doing its best to be invisible, a clueless young black bittern.  Obviously it wasn’t listening when its parents gave it the talking to about bitterns hiding coyly in the riverside rushes.

Looking towards Tuggerah Lake from the Wyong River mouth
Juvenile black bittern

And of course, the contractual obligation pelican on a post.  Thanks your offerings, this sunny Sunday, Wyong River.

Pelicans on the Wyong River in late afternoon
Standard

Posted by

Posted on

June 23, 2015

Posted under

anthropocene, Geology, History, national parks, natural history, Seasons, Soil

Comments

8 Comments

Midwinter lagoon

Bombah Broadwater in the gloaming

It’s past the shortest day of the year, but, in spite of her scrapes and dings, Egg the elderly wooden kayak doesn’t seem to be ready for drydock yet.  Perhaps it’s that last unseasonable whirl of autumnal warmth, caught alongside the coast in the East Australian Current, that’s keeping the sea a balmy 20 degrees.  Or perhaps it’s just the lure of still, winter water all around.

Since Egg was first laid in our driveway a year ago, I’ve been seeing Sydney differently.   Those long roundabout routes from A to B via M and Q and P, punctuated somewhere along the way by a bridge or two, suddenly make sense.  The city of roads and buildings retreats and, I feel, just out of sight on every side, the presence of water.
.
The Hawkesbury estuary
Upper reaches of Berowra Creek, a hop skip and jump from the Hornsby Westfield

This is our backyard, encircled by the salty embrace of the Hawkesbury estuary.  But it doesn’t end here, with the secretive topography of flooded river valleys. All the way up (and down) the New South Wales coast, the shoreline is flanked by coastal lagoons. I’m not complaining, even the tiniest little bit, about all these sheltered waters.  But I’ve started to wonder what geographic accident has given a timid canoeist so much to feel grateful for.

Along with marshes and flats, coastal lagoons make up maybe 10% of the world’s seaboards, and in NSW lots of us live by them, many more than by the ocean itself. Lagoons (or wave-dominated estuaries – there are ongoing hissy-fits around these definitions) appear where low-lying plains, rather than dramatic cliffs, meet a shallow gently sloping seabed.  Usually, they are found on shores shaped mainly by waves rather than big tides, with underlying rock that crumbles nicely into beach sand not finer, silty sediment.

The more sand the better – perhaps our generous continental shelf harbours this bounty from a time when the Sydney Basin was a enormous braided river delta, like the Ganges today.  But you don’t want too much rain – lagoons are usually fed by an underwhelming little creek or even just groundwater – that doesn’t (or doesn’t often) burst through the land between waterway and ocean.

Dawn breaks over the barrier between Bombah Broadwater and the open sea

To make a lagoon*, you need a barrier to the open sea.  In the nineteenth and first part of the twentieth century, coastal geomorphologists duked it out over just how these barriers were born.  Did breaking waves make for ever-rising off-shore sand bars?  Did encroaching seas submerge coastal dunes? And then there’s the third, attractively named “spit accretion theory” (Davis and Fitzgerald, 2004).  Not, as it might sound, a creation myth where bunyips drool into puddles between the dunes; just sand clinging to rocky headlands as it is carried along the coast by the (delightfully piratical) longshore drift.

It turns out that everyone was right, at least some of the time.  Which is nice.  It’s hard to keep the heat in a scientific controversy when lots of the evidence, hidden beneath the surface of the sea in the first place, has been washed away or covered over during the last few millenia by terrestrial silt or aeolian sand.  Who could be angry with such mellifluous and frankly otherworldly-sounding geomorphologies in play?

Pelican landing on Bombah Broadwater

Most lagoons have only been around for a little while, geologically speaking, formed after sea levels began to rise as glaciers melted 18,000 years ago or thereabouts. Many, like Narrabeen Lake, which we whizzed round on our bikes in the company of half the population of the North Beaches a few weeks ago, are even younger, not seven thousand years old. A blink of the eye for people who were here 50,000 years before.

Strangely, lagoons move.  Today’s surfers walk across the relics of yesterday’s drowned lakes.  Barrier beaches migrated landward, emerging from the ocean just as “marine transgressions” (that’s advancing oceans, not the naughtiness of waves) slowed.  Shaped in stable times, coastal lakes still don’t hang around for long.  This shouldn’t surprise me – I know that, despite appearances, beaches are really rivers of sand.
.
If the tides were higher, if the rivers was faster or siltier, if Australia wasn’t so seismically serene, the lagoons would fill up and dry out or be washed away, and the cormorants would have to hunt elsewhere.  In fact, for all our dredging and draining, it’s happening right now.  Like life itself, coastal lagoons are a transitory phenomenon, a passing pleasure.
.
Surfers floating over the relics of yesterday’s lagoon
Narrabeen Lake
Black swans in Narrabeen Lagoon
(Little?) Black cormorants
Intermediate egret in Narrabeen Lagoon
But sometimes, under the fresh sand and brackish water there are older and odder things. The beautiful Myall Lakes, where we not long ago spent a glorious weekend, lie in the bed of an ancient river, separated from the sea not just by dunes that arrived ten minutes ago (okay, 2,000 years ago) but also by the Inner Barrier, deposited before the last glacial maximum and thirty times older.
.
And then there’s the gyttja, something so very special it’s found nowhere else in Australia, and helps qualify Myall Lakes as a unique protected wetland.  What is it?  Well, rotting pondweed.  No, I’m underselling it: it’s up to 70cm of  “a highly mobile and organic mud that has a gelatinous appearance”, a “flocculent green–brown material” (Drew et al 2008), “an uncompacted, anoxic and sulphurous ‘ooze'” made from “the decomposition of charophytes, macrophytes, cyanobacteria and algae”.  Strangely, not so much about the ooze in the National Parks brochures.  But it’s an ooze that’s been there for, perhaps, a thousand years.
Dusk on Bombah Broadwater
Looking west at dawn on Bombah Broadwater
Canoeists in the gloaming
Eric the Egret on the Bombah Point Ferry
Glorious Angophora
Reflections on the tea-brown waters of Myall Lakes
Still morning on Two Mile Lake

I’ve been thinking about lies beneath the surface of the water and the windblown sand.   But paddling through the Broadwater two weeks back, in a startling moment I found myself not gliding above the mysteries of quiet waterways, but surrounded, right amongst it.  A huge flock, a murmuration almost, of little black cormorants, perhaps returning from a fishing trip, passed above and on one side and on the other without a single cry but with a sound I’ve never heard before: the white noise of hundreds and hundreds of moving wings.

The sound of the midwinter lagoon, all around me.

Little black cormorants murmurating

* Be warned: there’s a chance my account of the origins of coastal lagoons is completely wrong.  After all, the New South Wales coast “has provoked many questions and various degrees of controversy” (Thom, 2010, 1238).  And perhaps it’s “premature to attempt a comprehensive analysis of coastal lagoon evolution and dynamics when so many lagoons have been so little studied” (Bird, 1994, 13). In case you want to check my workings:
References
  • Bird, Erik (1994) “Physically setting and geomorphology of Coastal lagoons”  in Kjerfve, B. (ed) Coastal Lagoon Processes, Elsevier
  • Davis, R. and Fitzgerald, D. (2004) Beaches and Coasts, Blackwell Science
  • Drew, Simon Iona Flett, Joanne Wilson,Henk Heijnis, C. Gregory Skilbeck (2008) “The trophic history Myall Lakes, NSW, Australia”  Hydrobiologia 608
  • Eyre, Bradley and Damien Maher “Structure and Function of warm temperate east Australian lagoons: implications for natural and anthropogenic changes” Coastal Lagoons: Critical Habitats of Environmental Change, dited by Michael J. Kennish, Hans W. Paerl
  •  Martin, Louis and Jose Maria Landim Dominguez (1994) “Geological history of coastal lagoons” Kjerfve, B. (ed) Coastal Lagoon Processes, Elsevier
  • Masselink, Gerhard and Hughes, Michael (2003) Introduction to Coastal processes and geomorphology, New York, Oxford University Press
  • Thom, Bruce, Hesp, Patrick, Bryant, Edward (1994) “Last glacial ‘coastal’ dunes in Eastern Australia and implications for landscape stability during the Last Glacial Maximum” Palaeogeography, Palaeoclimatology, Palaeoecology 111 (3-4)
  • Thom, Bruce (2010) “New South Wales” Eric Bird (ed) Encyclopaedia of the World’s Coastal Landforms, Springer