Friday, 27 November 2015

Rhapsody in Blue Ringtail


Before starting to read, consider if you'd like to listen to George Gershwin’s Rhapsody in Blue while you read this post - if so you could try this link - https://www.youtube.com/watch?v=eFHdRkeEnpM


Last Summer I introduced myself to the amazing world of dragonflies and damselflies in the Canberra region. Prior to that I’d taken opportunistic photos of some fairly spectacular dragonflies (see for example earlier posts on Cape Dragonflies and Top end Dragonflies), but this was a concerted and systematic effort to try to find out what was present in the various watery habitats of the ACT.

At the end of the season I had seen and photographed 32 of a total of somewhere around 50 species that I think are likely to occur in the ACT (based on my interpretation of the Theischinger and Hawking 2006 Field Guide and occurrence records in the Atlas of Living Australia). Some of these were featured in an earlier post, Damsels - Down at the Local.

This season, apart from wanting to find as many as possible of the expected species I didn’t pick up last year (I’ve got two so far – Slender Ringtail and Powdered Flatwing), I’ve been trying to get a better idea of the time and sequence of emergence of dragonflies and damselflies after the long Canberra winter. 

A teneral (recently emerged immature) female Slender Ringtail Austrolestes analis, 24 Oct 2015.

Male Powdered Flatwing Austroargiolestes calcaris, Orroral Valley, ACT, 8 Nov 2015.

So far it is pretty clear, and not surprising, that the first emergences occur in the shallower water bodies at lower elevations (presumably because the water warms more quickly than water bodies that are either deeper or at higher elevations). The earliest species I saw, in mid-September, were Wandering Ringtail and Tau Emerald at a small pond at the local golf course. And I’ve only just in the past week or two (i.e mid-November) started to see the occurrence of river dragonflies in the lower reaches of the mountain rivers.

One of the most spectacular emergences I’ve witnessed this season has been at the large pond at the entrance to the National Arboretum. I drive past this most days on my way to and from work, but had always considered it to be fairly uninteresting and sterile – the pond, and arboretum, are still in a fairly early stage of development. I was in for a shock!


My first visit to the pond was on 17 October, and I wasn’t expecting much – just filling in surveyable sites really. And at first there wasn’t much to be seen along the narrow muddy edges fringed with rushes. But as I approached the end of the pond where the run-off from the surrounding slopes enters, the numbers of Blue Ringtails and Red and Blue Damsels increased, and there was also a single Australian Emperor and a few Tau Emeralds.

Adult male Blue Ringtail Austrolestes annulosus, Australian National Arboretum, 9 Nov 2015. 
A tandem pair of Red & Blue Damsels Xanthagrion erythroneurum, 9 Nov 2015.

Three weeks later when I returned, on the afternoon of 9 November, the numbers of damselfies had increased greatly and I estimated a total of at least 300 Blue Ringtails and probably about 60 Red & Blue Damsels, just at that end of the pond. The large number of teneral (immature newly emerged adults) Blue Ringtails I saw in the clumps of rushes and tall grasses bordering the pond indicated the population is still on the increase. The emperor and emeralds were still there, and I also picked up a handful of fairly newly emerged Common Bluetails.



Newly emerged (teneral) male Blue Ringtail. The areas of pale orange will eventually mature to a bright sky blue. During this vulnerable stage, when they are comparatively soft and weak-flighted, they tend to stick to the safety of dense grasses and other vegetation.



A teneral female Blue Ringtail.


The following photos attempt to convey a sense of the intense activity at the pond.







Perching spots were at such a premium that the different species even tolerated each other briefly. 


Blue Ringtail and Red & Blue Damsel sharing a perch.

Pairing up was a clear priority...




The protagonists of this newly established pair were a little awkward and had some trouble knowing just how to get it on, but eventually figured it out. 




Nuh-uh - wrong!


Let's try that again...
nearly there...
Ahh - yes, that feels right!

There was a lot of competition involved, leading to some pretty debauched behaviour. This male tried his luck with a female who was already paired up...




...and this one even tried it on with a hapless female who was all but dead and was floating on the water!




There were swarms of ovipositing tandem pairs of both Blue Ringtails and Red & Blue Damsels - presumably there were suitable water plants and twigs just below the surface that provided prime egg laying sites.




Both Blue Ringtails and Red & Blue Damsels are species which will totally submerge when laying eggs, the female dragging the male below the surface as she works her way deeper and deeper down a submerged plant or twig.


Two pairs of ovipositing Blue Ringtails. The lower pair is completely submerged; the upper pair is still working its way down the substrate, while another male flies past.

But not all had a successful or happy ending!




This is the biggest massing of damselflies I’ve yet experienced. Which is interesting, because last season, the only Blue Ringtails I recorded were a couple of males at the local golf course dam in November and December. This year I’ve already seen them in reasonable numbers at Acton Beach on Lake Burley Griffin (deeper water), and the lower reaches of the Gudgenby River (admittedly at still water of the pondage created by a weir). It’ll be interesting to see if they tend to be an early season specialist. Or whether this year might be a good year for them whereas last year wasn’t – for whatever reason. I have no idea yet how much variability there might be from year to year.

Another thing that is intriguing me for the moment is the absence so far of any Blue Skimmers which are normally very common. Last year, I saw my first Blue Skimmer on 26 October and that was in the backyard so I wasn’t even looking for them. 

Like with nearly everything – the more you find out, the more questions arise to be answered. But then isn’t that the fun of it?




4 comments:

  1. Hi Harvey,

    I work for the Arboretum and am so glad to see your stories and photos about the dragon and damsel flies here. Thank you. When you say the large pond, do you mean the front dam near the main entrance to the Arboretum? There is also a pond or dam near the cork oaks that usually has lots of frogs, so may also have dragon and damselflies. We have 4 dams altogether and an ephemeral pond in Forest 20. For personal interest I also participate in Frogwatch here at the Arboretum and we have recorded 8 species in the dams/ponds. The Arboretum is full of biodiversity and it's growing all the time. You have taken some terrific photos here. I wonder whether you would be willing to share your photos and allow me to use them on our website and in flyers/fact sheets and social media about the Arboretum? I can include the photo credit whenever possible. Please email me if you are happy for me to use your photos: lynne.sealie@act.gov.au Regards, Lynne Sealie, Science Communicator, National Arboretum Canberra. 02 6205 3304.

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  2. Hi Harvey
    That is spectacular! Great pics of such mobile creatures. I hope you are able to continue your obs at the Arboretum so that picture can be built up over the years as the forests grow and the habitat slowly changes, along with the climate.
    Are there ways that you can quantify your observations of numbers?
    Cheers
    Roger

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  3. Great stuff thanks Harvey - I now have another reason (ie in addition to the STEP garden) to go the arboretum, and shall do so. Dragonflies and other inverts are projects for my hypothetical retirement.

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  4. It would be interesting to know when you took those pics. I've just come back from there, and there are big numbers of the lovely Blue Ringtails where you described, and also in the NE corner of the pond. However, no mating activity, and not a single Red and Blue Damsel. I had a look along the edge of the big pond at North Weston (behind the Cotter Parks Depot) too, but not much happening there.

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