Loves and leaves

Yet more lock-down luck.  Company, space, a rambling garden desperately requiring attention, three national parks in walking distance and enough devices to make home learning while working full time quasi-feasible – I already have plenty to be grateful for.  And now, the collared sparrowhawks are back, getting friendly in the neighbour’s pine tree.  They have perfect timing.  It’s just at that point in the lockdown – eight weeks in – when even the most avid homebody/hoarder is running out of distractions.  I’m not saying that trying to get a photograph of the local raptors having sex is my only reason to get out of bed in the morning, but it is a reason.

Morning does seem to be the time for it.  No pictures – this is a family-friendly blog, after all (nothing to do with me being slow on the draw with the zoom lens).  When the sparrowhawks are around, we usually hear them soon after sunrise.  There’s relentless calling from near the top of a tree – mostly, I think from the female.  The male perches, in a diffident kind of way, in a nearby branch.  Then they’re at it, with a brief distinctive flurry of calls.  Afterward, the male shuffles or flaps a distance away on the branch, studiously avoiding eye contact.

The one time I managed to watch the process from go to whoa, afterwards the female chilled out in more or less the same spot high in the pine tree, catching the morning rays, and keeping an eye out for small bird snacks.

Meanwhile, what I think was the male (though this might be a gender stereotype), started attempting some DIY.  Collared sparrowhawks build a shallow nest of stick, high in the canopy, and line it with fresh leaves each year.   This pair seem to be using the same spot in the very top of the neighbour’s tree, notable for its inconvenient lack of a line of sight from my place.

Watching the male gathering construction materials, I’m once again reminded of the limitations of the sparrowhawk’s modest beak and  delicate legs for this kind of building work.  The bird seemed to spend a lot of time eyeing up flimsy looking twigs and then flailing around with its wings in an attempt, mostly unsuccessful, to break some bits off.

 

As you can see, this bird had a red-hot go at getting some twigs from dead branches on one of the usual pine trees.  Eventually, however, the nest-building one of the pair got a bit experimental.  The liquidambar in our front yard – stripped of its leaves by winter, and not so good for ambush hunting – got a visit, solely for construction purposes.

However, some of the neighbour’s shrubs with thin whippy stems and fine needle-like leaves and seemed to be nest-material of choice.

Even so, the process was neither dignified nor ubiquitously successful.  These photographs are both fails.  Photographic fail – frustrated nest builders crashing around in the shrubbery are not an easy capture.  Also, nest building fail – neither of these twigs made it back to home base.  I did, however, see more success on another round of visits to this same bit of greenery the next day.

And they’ve kept at it, with occasional success.

Watching the nest-reno in action has made me reflect on our luck in having these gorgeous critters hanging out nearby – and  on what kinds of habitat create that kind of luck.  Sparrowhawks need tall trees to nest in. This pair (assuming it’s the same one returning each year) nest in one pine tree, and use a sequence of three others nearby as regular hunting spots.  Thanks to lots of greenery, we have loads of undemanding smallish birds on the premises of the right size for raptor snacks – little and red wattlebirds, chicks of the ubiquitous brush turkeys and, of course, loads of bloody noisy miners.

I’ve definitely seen the sparrowhawks devouring birds that we don’t see at our place though – I’m sure they hunt in the national park that’s 500 metres down the hill.  Here’s one of the fledglings from a couple of years ago, chowing down on what I think is a white cheeked honeyeater – I’ve never seen one at our place, but they’re pretty common in the bush not far away.

In the two seasons when they successfully raised chicks, the fledglings seemed to practice short hop flights from one pine to another.  The liquidambar in our yard is an occasionally hunting spot in summer, and I do wonder if the cicadas that appear to feed on its sap in mid-summer offer useful meals for the chicks.

And then there’s the necessity for nest-lining trees with appropriately flimsy branches.

Sparrowhawks are generalists and live all over the place – everywhere except the most arid regions of Australia.  So they’re obviously not too fussy about the finer details of their immediate environment.   They’re pretty low key around people and don’t seem to mind suburbia.  I wonder how much they need the bushland I’m finding so sustaining in lock-down.

The sparrowhawk pair isn’t the only birds aware of the value of this bit of floristic real estate, though.  I’m pretty sure currawongs took some of the sparrowhawk’s nestlings in previous clutches, and I wonder whether the presence of these smart and social predators has kept the pair away for the last three years.  But yesterday a bit of argy-bargy with another of the locals – a family of kookaburras.  I’ve been seeing them around a bit more than usual this winter, surveying the scene from our dawn redwood and the remnants of our long-dead pine trees.

Yesterday I wandered up the drive to see if I could capture any trysts or DIY activity, and there was a cheeky kookaburra in the exact  spot I saw the sparrowhawk chilling in the day before.  And another, on a second favoured hunting perch, further up the tree.  The sparrowhawks were in the vicinity, but as soon as one landed in that pine, the kookas were after it.

Here’s a deeply discombobulated sparrowhawk, catching its breath a few metres away.  A minute later, the kookaburras were back and the pair of raptors hightailed it into the distance.

I feel stupidly anxious about this, for some reason.  Every year about this time, we hear the sparrowhawks and I’m always hoping they’ll hang around and try to raise some chicks again.  For the last couple of seasons we’ve been disappointed.  But this year, silly as it seems, it feels a bit more high-stakes, and not just because we’re stuck at home with near-infinite opportunities for bird watching.  It feels symbolic even.  If this avian couple’s romance and nestbuilding comes to fruition, somehow it signifies that my little family will stay safe here too, safe and sane and together.  And if not… these things somehow seem less assured.

But of course, that’s a nonsense.  Birdwatcher magical thinking.  If the sparrowhawks find a better place to nest, and our trees get a different set of inhabitants, there’ll still be things to do, birds to listen out for, a different family to get to know.

The previous adventures of our local sparrowhawks

Sex, nests and dogfighting

Collared sparrowhawks vs Pacific bazas

Motherhood on a windy day – the sparrowhawk chick grows up

Death and sibling rivalry

Sparrowhawk summer

Battle of the baby birds

Welcome beautiful stranger

Warbling in lockdown

Kayak on still river water at dawn with reflections showing the sky

Six weeks into a Sydney lockdown.  Everyone confined to their homes with occasional outings for food and exercise no more than a few ks away.  I feel super lucky that this bit of Dyarrubbin still falls within the 10 k radius I’m allowed to stray from my house. Berowra Creek, at the end of my street, is super quiet at the moment, the houseboats rocking empty at their moorings, jet-skis banished – only the locals heading out in ones or twos for some fresh air.

It seems fitting that the “feature wildlife” of my escape to the river last weekend was also a local – Sydney’s only endemic bird, origma solitaria, the rockwarbler.

These little birds are only found within 250 km of Sydney, hopping around mostly on Hawkesbury sandstone, though I’ve hear they also pop up on the limestone and granite, where it is to be found.  Their range on the coast extends from Mollymook  to Raymond Terrace, and they can be found as far west as Orange and in the north can be found up in the beautiful Coolah Tops National Park, according to the CSIRO Australian bird guide favouring “exposed, dissected rock outcrops…from coast (including sea cliffs) to high plateaus  of the ranges” (2017, 340).

Rockwarblers are not uncommon – despite their restricted range they’re flagged as of least concern, conservation-wise – though they don’t appear to inhabit cities like Newcastle, Sydney or even Wollongong or Nowra.  On my noodling 12 k paddle last weekend I spotted one pair busily feeding and nestbuilding on rocks by the waterside, and then, having tuned my ear to their high pitched calls, spotted another pair doing much the same, on the return journey.

I don’t see them on every trip out but I’ve observed them behind golden beaches on Cowan Water and in rocky bays near Dangar Island, and even in one of the spots  at Berowra Creek with the most foot traffic, at Washpool Creek where the Great North Walk meets the estuary.

The rockwarbler is an unremarkable looking little bird – “a small, plump, dark brown-grey bird with a cinnamon-tinged face and forehead, a dull white throat speckled black, reddish-brown underparts”, almost the definition of the LBB – but has some interesting habits.  It makes pendulous domed nests that hang in darkened overhangs and caves in the rocky terrain it prefers – apparently its common name used to be “hanging dick”.  Who says all folk wisdom  needs to be kept alive, eh?

I spotted my first rockwarbler for the day collecting what looked like nest material – roots and possibly spider webs  in the exposed root system of toppled trees on the shoreline. She flew off intermittently into a group of boulders behind some casuarina trees – I couldn’t get a clear shot of the crevice she seemed to be returning to, so no photo of a hanging dick, for which you might well be grateful.

Despite all this, I’d like to get a glimpse of a nest – the description in Birdlife’s online site have a hard core goth appeal:

Made from grasses and plant fibres and coated with spider webs, [the nest] is attached to a rocky overhang or roof of a cave by spider webs, which the bird hammers into place with its bill. They are then covered with saliva to hold them in place

You can see in these pictures that the spot I saw my first pair of rockwarblers has been a important place for humans as well as non-human animals for thousands of years.  The soil here is thick with oystershells, left by the custodians of this country over the centuries, and now woven into the earth in scores of places right along the shores of Berowra Creek.  Everywhere you look around here there’s a midden.

Rockwarblers look a little bit like northern hemisphere robins and seem to have a similar outgoing personality – “confiding” in the words of the CSIRO blue bird book.  This bird and its mate, that soon arrived on the scene, didn’t seem particularly disturbed by a kayaker loitering nearby with a camera, and I managed to drift quite close while they scoured the rocky shore for largely invisible food.

I’ve read that rockwarblers are primarily insect eaters although Carol Probert has reported seeing nectar drinking in some she watched in the Blue Mountains. No evidence of this here but there seemed to be plenty to eat.  This pair traversed the rocks briskly, picking mysterious things from amongst the moss, and even dipping beaks into the little bowls comprised of previously-opened mollusc shells on the rocks.  I’m not sure  if the rockwarblers were scrounging for critters that had found a home in these tiny rockpools.

There were plenty of insects about in the lee of the rocks, but i didn’t see any of the birds I watched that morning snatching a snack from the air, despite the temptation.

What I did see – once with each pair of birds – was what I think were nuptial gifts – one bird feeding the other snack, perhaps with romantic intentions.  I stress I did not witness any subsequent feathered intimacies but with birds you blink and you’ll miss it, so that doesn’t necessarily mean a lot!

Here’s pair number one, coming beak to beak.

And the second pair

I think I can see a insect leg sticking out from the crumb in the beak of the bird with the tuft of feathers on its back.  I guess these scenes could have been adults feeding juveniles, which look similar to the grown-up rock warblers, only paler in colour, but I didn’t hear any pitiful calls from the recipients and given the time of year – roundabout the beginning of breeding season for many birds – a romantic gesture seems a bit more likely.

The rockwarblers were pretty friendly to me but also to the other little birds hopping around the nest area, particularly a family of variegated fairywrens that seemed to follow them as they hopped about round the edge of the water.  The warblers kept their feet mostly on rock, the wrens mostly flitting from twig to twig in undergrowth nearby. If there’s dietary competition between these little birds, it’s a very friendly one.

In fact, I suspect this was more like the mixed-flock foraging that have been noticed in many parts of the world in wintertime, when different species of small insectivous birds move around feeding as a group.  Maybe the rockwarblers’ hopping stirred up some flying insects for the wrens to eat?  Some researchers have found that variegated wrens, sometimes hang out with “friends” from other species whose territory overlaps with their own, sharing the defense of that territory, travelling and foraging together. This benefited the wrens a lot – they “spent more time foraging, were less vigilant [and] had greater first-nest fledging success” (Johnson, 2018, 821).  I wonder if the wrens were as friendly as this with my rockwarblers?

The atmos not so friendly amongst the waterbirds feeding nearby.  I watched a whitefaced heron repeatedly asserting dominance over a striated heron on a sequence of estuarine patches, as I trekked back the put-in.  Berowra’s ubiquitous waders are higher up the pecking order than ubiquitous lurkers it seems.

And then, just as I turned the corner to the marina, high over all, the alpha local of these lands.   A wedgie soaring silently, surveying its domain.

 

References

Davis, William M and Recier, Harry “Winter mixed species foraging flocks in acacia woodland of Western Australia” Corella, 2002, 26 (3), 74-79
Menkhorst, Peter; Rogers, Danny; Clarke, Rohan; Davies, Jeff; Marsack, Peter; Franklin, Kim The Australian Bird Guide, 2017 CSIRO Publishing
Probets, Carol ; Palmer, Grant ; Fitzsimons, James “Nectarivory in the Rockwarbler ‘origma solitaria’ Australian field ornithology, January 2019, Vol.36, p.34-35
Smith, Peter ; Smith, Judy “Re-use of a rockwarbler ‘origma solitaria’ nest over a 13-year period” Australian field ornithology, 2012-06-01, Vol.29 (2), p.77-82
Other locals in our backyard