Top End Dragonflies

In the second half of May, Karen and I took off for Darwin. The minimum overnight temperatures in Canberra in the days preceding our departure had bottomed out at -6 C and we were very much looking forward to the tropical heat of Darwin: low to mid 30s during the day and overnight dropping to as cold as 20 C!

The underlying reason for the Trip was Karen’s niece’s wedding (thanks Emily!), but we were going to take advantage of the opportunity and finally get to Kakadu National Park. And Katherine Gorge in Nitmiluk National Park.

Wedding on a Darwin sand bar.

Part of the Nourlangie (Burrunggui) Rock outcrop, Kakadu National Park.

Sunset cruise on Katherine Gorge, Nitmiluk National Park.

There are lots of stories that could be told, but this post will focus only on the dragonflies I saw on the trip. One of the things about the tropics is that dragonflies are around even in the months of the southern winter. The last dragonflies I saw in Canberra for the season were a few Tau Emeralds, back on 18 April, along Sullivan’s Creek where it ‘flows’ through the Australian National University on its way to Lake Burley Griffin. And that was about a month after most species had disappeared from the local rivers, wetlands and ponds around mid-March.

The northern parts of Australia are very much dominated, in terms of dragonfly fauna, by the very large and cosmopolitan family Libellulidae. And damselflies, the common and obvious ones at least, are predominantly represented by the Coenagrionidae. On this trip I encountered a total of 19 species of dragonflies and damselflies. Of these, four were Coenagrionid damselflies (two of which were new for me), there was the Australian Tiger from the family Gomphidae (or Lindeniidae by some taxonomies), and 14 were Libellulids of various kinds (including six new). So eight new species for the trip which I didn't think was too bad. 

Just to put this into context a bit – although I’ve taken photos of dragonflies that caught my attention in the past, including the stunning Cape York ones described in an earlier post (see Cape Dragonflies), it’s only been in the past 12 months or so that I’ve really looked for dragonflies in a more systematic and concerted way. 

The Slender Skimmer Orthetrum sabina was one of the more common of my new species.

The species I’d already seen, either on a previous trip to Darwin in 2008 for Karen’s other niece’s wedding (Thanks Mel!), in tropical Queensland, or just elsewhere in Australia, were:

Eastern Billabongfly

Common Bluetail   

Australian Tiger

Blue Skimmer

Palemouth

Scarlet Percher

Wandering Percher

Painted Grasshawk

Red Arrow

Graphic Flutterer

Common Glider

And the eight new species from this trip are:

Blue Riverdamsel

Colourful Bluetail

Red Baron

Speckled Skimmer

Rosy Skimmer

Slender Skimmer

Chalky Percher

Pygmy Percher

On this trip, the first opportunity I had to look for dragonflies was at the Sanctuary Lakes in Gunn, a suburb of Palmerston 20 km south-east of Darwin. These lakes were just down the road from where we were staying with Karen’s sister, Jen, and her husband Steve, so I ended up going there three times over our first weekend. The first visit, on the Friday afternoon not long after we had arrived (no point wasting time!) I was essentially bird watching, and sadly without camera, but did notice several Common Bluetails and Eastern Billabongflies, both species familiar to me and common in Canberra. But over the next two visits (with camera) I also picked up Blue Riverdamsels and Colourful Bluetails (both new as indicated above), a Blue Skimmer and Wandering Percher (again common in Canberra) as well as a Red Arrow which I’d only seen once previously (in Gladstone, Queensland), and several Slender Skimmers and a Pygmy Percher (both new).

So almost half of all the dragonfly species I saw on this trip, I first saw at these local suburban lagoons.

A pair of Common Bluetails Ischnura heterosticta 
in the 'wheel' position, i.e. mating.

A pair of Eastern Billabongflies Austroagrion watsoni mating.

A Blue Riverdamsel Pseudagrion microcephalum, the first of my new species.

A male Colourful Bluetail Ischnura pruinescens - new species number 2!

Blue Skimmer Orthetrum caledonicum on a water lily bud.

Wandering Percher Diplacodes bipunctata,
also on a water lily bud; obviously very convenient perches.

A male Red Arrow Rhodothemis lieftincki, brilliant in the bright sunlight.

Despite being very common in the right places, this was my first Slender Skimmer Orthetrum sabina.

Another Slender Skimmer Orthetrum sabina.

And my first Pygmy Percher Nannodiplax rubra,

Before leaving Darwin and heading across to Kakadu, we made a quick visit to Buffalo Creek, at the northern limit of peri-urban Darwin. The purpose of this visit was to try (yet again) to see a fairly large but very elusive bird, a Chestnut Rail Eulabeornis castaneoventris, for which Buffalo Creek has long been a supposedly likely spot. But the tides and the activity of boat and fishing people were against us and I dipped for the fifth time. But I did see the first of several Painted Grasshawks in some roadside vegetation on the way back. Lighting and the angle of the sun can make a difference, but I have the impression that the Top End versions of this species I’ve seen have in general been less intensely coloured than those I've seen in Cape York. I don’t know how valid this assessment might be, or whether it's just artefactual of my limited experience with the species.

Painted Grasshawk Neurothemis stigmatizans.

Our first stop on the drive across to Kakadu was at Fogg Dam, a beautiful wetland spot, well-known to birdwatchers. And it impressed as much as it had on our first visit there in June  2008. On that earlier trip I had photographed a dragonfly that turned out to be a Red Swampdragon. It remains the only individual of this species I’ve seen.

Red Swampdragon Agrionoptera insignis, at Fogg Dam, about 60 km east of Darwin (June 2008).

Along the causeway that divides the lagoon in half, I saw a few more Slender Skimmers (now old mates!), a few Graphic Flutterers, and my first Chalky Percher. There were also hundreds of Common Bluetails, mostly paired up in an apparent mating frenzy .

A female Chalky Percher Diplacodes trivialis on the causeway at Fogg Dam. New species number 5.

One of many such branches festooned with mating Common Bluetails Ischnura heterosticta.

I found it particularly interesting that there were such large assemblages of mating Common Bluetails. In Canberra, where they are also very common around lakes and dams, I've rarely seen them paired up. Lots of patrolling males, and lots of laying females, but very few seen in tandem or in the wheel formation (see comment in previous post Damsels - down at the local.)

Another interesting difference was that the male Common Bluetails I saw in the Top End all tended to have the humeral stripe very much reduced relative to those I’m used to in Canberra. Also, some of the females of the mating pairs were as blue as the males. I’ve not seen this in Canberra, where all the females I’ve seen so far have been of the more typical dull brownish colour with at best an orange or greenish tinge to the thorax. Apparently this colour form variation in females is not especially uncommon in some Coenagrionids, including Ischnura. It's been hypothesized that, although this might appear to be disadvantageous if it reduced the likelihood of mating, it might also be advantageous if the male-coloured females were subject to less harassment during egg laying in high population density situations (page 52 of Dragonflies of the World by Jill Silsby, 2001).

The female of this mating pair of Common Bluetails Ischnura heterosticta is of the male or blue colour form.

Reduced humeral stripe of Common Bluetail - mating male in Darwin

Normal humeral stripe of Common Bluetail - mating male in Canberra

We left Fogg Dam and headed east towards Kakadu, stopping briefly at the Mary River Billabong. It was hot, and getting close to lunch time, so we didn’t stay long, but I did pick up some more Eastern Billabongflies, Colourful Bluetails, a Wandering Percher and my first Australian Tiger for the trip.

Australian Tiger Ictinogomphus australis.

Single individuals of Australian Tiger, Red Arrow and Pygmy Percher were also present at Flying Fox Creek (within Kakadu, now at  a small creek crossing where we stopped to have a quick picnic lunch). 

Another Australian Tiger at Flying Fox Creek...

... and getting accustomed to seeing Pygmy Perchers.

Our first real stop in Kakadu was at Mamukala Wetlands. Here I saw several Graphic Flutterers, a Wandering Percher, and the first Common Glider for the trip.

Graphic Flutterer Rhyothemis graphiptera.

Graphic Flutterer Rhyothemis graphiptera.

We finally made it to Jabiru, where we’d be staying overnight, and just before sundown we had a quick look around the lake there. The only dragonflies I saw were Graphic Flutterers and a couple of Scarlet Perchers, but they were interesting for their evening behaviour. The Graphic Flutterers were swarming in clouds of up to 20 or so, and both they and the perchers were alighting on the highest tips of various palm or pandanus fronds. I speculated on whether the flutterers were swarming as a pre-roost behaviour, or whether they might have been following swarms of small midges or other potential food insects, but I really don't know. 

Late afternoon Graphic Flutterer

Part of an evening swarm of Graphic Flutterers

A pre-roosting Graphic Flutterer

And a parked percher amidst the pandanus.

The next day, after an exhilarating short flight over the western Arnhemland escarpment and East Aligator River, we headed down to Nourlangie. At the nearby Anbangbang Billabong we again encountered a few Graphic Flutterers and a Pygmy Percher. Higher up, a lone Common Glider posed beautifully on the top of a twig on a bush on the rocky escarpment of the Nawurlandja lookout. At Nourlangie itself near the rock art galleries, well away from any obvious water, were a male and female Painted Grasshawk.

Common Glider Tramea loewii at the Nawurlandja lookout.

Another take on the Common Glider Tramea loewii at the Nawurlandja lookout.

Female Painted Grasshawk Neurothemis stigmatizans at Nourlangi.

From there we moved on to the Gagudju Lodge at Cooinda, near the adjacent famous Yellow Water billabong and floodplains. We did the obligatory early morning cruise at Yellow Water, where my focus was on the birdlife. I was desperate to see a Great-billed Heron which are sometimes seen here (I’d not yet managed to see them around Darwin). The only dragonflies I noticed were a few Blue Riverdamsels, including one that had decided the pronounced eyebrow ridge of an Estuarine Crocodile was a far superior perching spot to any of the nearby emergent branches! (This was also the first Estuarine Crocodile, or 'salty', I'd ever seen).

A Blue Riverdamsel gets familiar with a Estuarine or Saltwater Crocodile.

After a fantastic buffet breakfast back at the Lodge, Karen and I decided to have a fairly relaxed day, so I spent a bit of time later in the morning just wandering about the grounds. There is a small jetty type affair on the Jim Jim creek just near our accommodation which provided access to some woodland and its birds as well as the creek. Here, in between ticking off birds, I photographed another Australian Tiger, but also a couple of other dragonflies that, after returning to the air-conditioned comfort of our room, I determined from the field guide to be Speckled Skimmers. 

But I couldn’t understand why the only photo in the field guide was of a dried museum specimen. It wasn’t until I got home to Canberra and started looking into things that I discovered how unlikely it might have been to have seen this species. It seems (based on the Atlas of Living Australia) that there are only half a dozen or so (museum) records of this species from Australia and that they were not known to occur in Australia until 1968 when John Watson collected a specimen from eastern Arnhemland. (The species was first described by Lieftinck in 1933 based on a New Guinea specimen). And, as far as I can determine, there are no previous photographs of a living individual anywhere. So I’m really chuffed to have seen these dragonflies and to have got the photos.

Speckled Skimmer Orthetrum balteatum - possibly the first ever published photo of a live individual in the wild?

Speckled Slimmer Orthetrum balteatum - Cooinda, Kakadu National Park.

To this point, all the dragonflies and damselflies I’d come across were associated with lagoons or riverine pools. At Gunlom, in the south west of Kakadu, we were up in the escarpment country with smaller faster-flowing creeks, but even here all the dragonflies I saw were still associated with slower-moving sections of water. I finally came across my first Rosy Skimmer, a female Red Arrow (which looks quite different to the bright red male), and another bright red species which I’m pretty sure is a Red Baron (also new). 

A Rosy Skimmer Orthetrum migratum - one I'd been wanting to see and now my 7th new species for the trip.

A female Red Arrow Rhodothemis lieftincki (compare to male in photo above).

I think I'm fairly sure this might be a Red Baron, Urothemis aliena.
Whatever, it was my 8th and final new species for this trip.

From here on I didn't see so many dragonflies. At Pine Creek I was focused on seeing Hooded Parrots, and at Katherine Gorge it was sunset anyway - stunning for the scenery but not so good for odonates. At Edith Falls we did see more Scarlet and Pygmy Perchers and Eastern Billabongflies. And in Darwin, we were of course finally concentrating on the wedding which was on the final day of our northern sojourn. 

But I did see a Palemouth at the picnic area at the outlet creek from Manton Dam on our way back to Darwin (I'd only seen a couple of these previously, in Gladstone in Jan 2014), and I was surprised to see a Chalky Percher right out on the intertidal rocks at Nightcliff in Darwin - so I'll just finish up with a couple of photos of them as this post has gone on for longer than I expected anyway.

A male Palemouth Brachydiplax denticauda.

Chalky Percher (immature male?) on tidal rocks at Nightcliff, Darwin.

It was an excellent trip. Not just for the dragonflies either - my next post will be on the new birds I saw...

But seriously, it was a fantastic trip - we finally got to Kakadu and Katherine Gorge, the weather was perfect, and there was lots of catching up with family, including weddings and new generations, which doesn't happen frequently enough. Good reason to return...

Broulee Interlude

At the beginning of May, after the first hard-hitting cold weather of Canberra’s autumn and before we headed off to tropical Darwin for a niece’s wedding, we headed down to Broulee on the NSW south coast for a long weekend. It had been planned for ages, having been booked for a discount price through one of those on-line discount provider set-ups. The timing was a little later than we’d have preferred, but at least it was very far from the madding crowds of summer school holidays. Always a good thing!

The weather was predominantly cool and quite windy. We did some essentially car-based touristing, including a drive down to the Bodalla cheese factory and café on one of the days, as well as a fair bit of local walking, but we had a mostly quiet relaxed long weekend.

Despite the windy conditions, this pelican thought it was a good idea to try to perch on the power lines down at the Mossy Point jetty.

When I tried explaining to it that this is not something that pelicans normally do, or are very good at, it just looked at me as if to say "what would you know!"

I’ve been to Broulee and adjacent Mossy Point plenty of times previously, but this trip was the first time we’d got around to actually walking right around Broulee Island. Not that it is strictly an island at the moment, being joined to the mainland by a currently well-vegetated tombolo (a tombolo is a sandbar that connects an island to the mainland or to another island). 

When I first visited Broulee, sometime in the early 1980s, the island was just that, and was accessible by foot only by wading across the shallow sandbar at low tide. Historically, the tombolo has been breached periodically by high seas. It was intact when the island was first surveyed by Thomas Florance in 1828 and remained so until 1873 when a severe storm resulted in the island being cut off from the mainland. Since then, the connecting isthmus has repeatedly been breached and reformed. The most recent breaches were in 1966, 1969, 1971, 1974, 1981 and 1988. The vegetation appears to be very well developed at the moment, and the sand quite high, and I suspect it would take a massive storm to break through. 

Approaching Broulee Island from the south. The tombolo now creates calm and beautiful beaches on both its southern and northern sides.

The view of the south-western corner of Broulee Island as seen from the middle of the tombolo. 

The rocks at the south-west corner of the island are frequently used as perching sites for various cormorants and other sea birds. The Little Pied Cormorants took off at my approach, but two of the four Great Cormorants hung around long enough for me to get a largely silhouetted shot of them. 

Great Cormorants Phalacrocorax carbo, back-lit by the afternoon sun.

A little further around the rocks a White-faced Heron was fossicking in the rock pools. Other birds we saw along the way included a trio of Sooty Oystercatchers, roosting flocks of Silver Gulls and Crested Terns, and a magnificent adult White-bellied Sea Eagle that soared right over our heads before sweeping up and over the Broulee headland. 

A White-faced Heron Egretta novaehollandiae works its way around the rockpools at low tide.

Exposed rock platform on the southern side of Broulee Island.

When we reached the seaward end of the island, I was surprised to see a single Grey Mangrove. Seemingly fairly old but rather stunted in its growth, it persists on the most exposed easterly extreme of the island, well back from the breakers, at the point where the exposed wave washed rock platform merges with the shingle slope before the vegetation proper begins. It stands alone, sentinel against the elements, with only a tiny patch of Beaded Glasswort (Sarcocornia quinqueflora), another hardy salt-tolerant plant, for company.

A hardy but stunted Grey Mangrove on Broulee Island. 

Mangroves, perhaps not intuitively, are not all related members of a single family of plants, but represent more than a dozen different families. A great example of convergent evolution, where a range of quite different plants have evolved independently to make use of the marginal habitat between land and sea. The Grey Mangrove (Avicennia marina) is, disputedly, a member of either the Acanthaceae or Verbenaceae families, though it is also sometimes included in its own family the Avicenniaceae (which is now generally included under Acanthaceae). Either way, these families are better known for their non-mangrove members.

The  flowers of the Grey Mangrove are small and compact, especially compared to the comparatively large and showy flowers of some tropical mangroves. Many mangroves also produce aerial roots - either as arching support roots, or often, and as is the case with the Grey Mangrove, as small peg roots or pneumatophores that project vertically out of the sand or mud and are exposed at low tide. These aerial roots act as snorkels and allow the plant to take up air at low tide.

Flowers of the Grey Mangrove are fairly small and not particularly conspicuous.

The Grey Mangrove is characterised by many peg roots or pneumatophores which help it breathe. 

The NSW NPWS Broulee Island Nature Reserve Plan of Management (see reference at end) states that "The shoreline rock platform has been colonised by a few grey mangrove plants (Avicennia marina var australasica)" - I guess that fits with the fact that the only ones I saw were this solitary individual and one much smaller plant desperately clinging to existence in the outer rock platform on the northern side of the island. A population of two!

Breakers on Broulee Island with Burrewarra Point in the background.

I’d assumed that Broulee Island had always been an isolated off-shore islet with little human history. Not so. The island is in Yuin country and the indigenous Yuin people of the area would no doubt have made use of the island for various purposes. European interest in the island began in 1828 when, as indicated above, Thomas Florance surveyed the area and called the island “Broulhee”, presumably a phonetically-derived version of the Yuin name. 

The Plan of Management is a great source of information on the island and it says that "As early as 1836, the growing number of European settlers in the region were using the bay on the northern side of “Broulhee” Island, marked on Florance’s map as Ark Harbour, as a place to load and unload goods, stock and people from anchored ships using small boats." 

"In James Larmer’s 1837 survey of Broulee, the island was referred to as East Broulee

and contained a village subdivision called “Boat Harbour”. It consisted of a grid of eight

streets - Oldrey Crescent, Sibella Terrace, McDonald Street, Huntley Street, East Cliff,

Signal Cliff, Hawdon Street and Fountain Street and 54 separate allotments."

While this development never eventuated, several buildings were constructed on the island including a hotel and several outbuildings. The hotel, a low shingled weatherboard bungalow near the edge of a cliff was built in 1840-41 by Captain William Oldrey, and was leased by Bernard McCauley in 1842 who named it the Erin-Go-Bragh (Ireland Forever). 

Broulee remained a tiny settlement and the Erin-Go-Bragh Hotel closed in 1844. It was

reopened in 1846 as the Union Inn, but it soon failed as well. By 1851, Broulee had a population of one. Sometime during the 1850s the hotel was moved to Campbell Street in Moruya, It was demolished in 1978. 

"Little occurred at Broulee until 1920 when shellgrit was collected from the northern side

of the island for use in cement production in Sydney. After World War II, a motorised

barge was used to transport the shellgrit from Broulee Island to a wharf in the Tomaga

River from where it was shipped to Sydney. To enable the barge to be loaded at the

island, a 50-60 foot long jetty was built together with a light rail track that carried a small

dump truck at what had become known as Shellgrit Bay."

The only remains of this European history on Broulee Island are some decaying remnants of the rail track and jetty, a few bricks, and a single grave. 

Two posts of the former jetty and a rusting single rail hint at the past European activities at Shellgrit Bay on Broulee Island.

Rusting rail track at Shellgrit Bay.

Shellgrit Bay on Broulee Island, festooned with washed-up seaweed. 

As we headed back around the southern edge of Broulee headland after completing our circuit of the island, the wind was whipping the spray off the tops of the waves, lit up by the lowering sun. There were quite a few surfers out enjoying the conditions, as were a bunch of spectators who seemed perfectly comfortable staying out of the water and keeping dry! 

What a great way to spend an autumn afternoon. 

Wind-whipped crests of waves at the southern side of Broulee Headland, or the northern end of Bengello Beach.

Surfers made the most of the conditions...

on waves that broke both right and left...

watched by long-shadowed spectators in the late afternoon sunshine.

References

Broulee Island Plan of Management: http://www.environment.nsw.gov.au/resources/nature/BrouleeIsNRpom.pdf

Mangroves:  

https://en.wikipedia.org/?title=Mangrove