A dam extravaganza

by Patrick Kavanagh

We’ve had a Little Pied Cormorant frequenting our dam recently and I thought I’d try to catch a photo of him. Birds were nowhere to be seen but as I sat by the dam I was able to see so much happening around me. There were myriad Blue Skimmer Orthetrum caledonicum dragonfly males, which from my reading on are the only ones of this species with the distinct powdery blue coating. Females are yellow and black, as are teneral males (having just emerged into adult form) but the latter are brighter yellow. The males were spending a lot of time chasing each other around the dam.

Male Blue Skimmer dragonfly.

The female Blue Skimmer.

Damselflies (which can be discerned from dragonflies because they fold their wings at rest) such as Eastern Billabongflies  Austroagrion watsoni and Aurora Bluetails were abundant amongst the water plants at one side of the dam.

An Eastern Billabongfly.

A male Aurora Bluetail.

Water Treaders (mesovelids) were skimming the surface of the dam and these mostly seemed coupled. Also more sedate in this area was a Scarlet Percher dragonfly and a Fishing Spider Dolomedes instabilis, which like the Water Treaders can skim across the surface of the water using surface tension to stay dry.

A pair of coupled Water Treaders.

A Fishing Spider on the floating pondweed.

In case I sound like I know what I’m talking about, I found Arachne.org and http://photos.rnr.id.au/ very helpful in identifying these species and can highly recommend a visit, as well as a visit to a dam near you.

A dangerous time

Grebes have featured a number of times recently, but at the risk of ‘grebe overload’ I thought the following observations worth sharing. Exploring one of the bush dams near South German Track I spotted two tiny (and I mean tiny!) shapes paddling amongst dead branches near the edge of the dam. They proved to be very recently hatched Australasian Grebes … surely not more than a couple of days old. The characteristic striping, which disappears rapidly as they grow can be seen on the plumage and even the bill.

Juvenile Australasian Grebe, South German Track, 26th January 2012.

Presumably the striping provides camouflage at a vulnerable stage of life.

Mysteriously the parents were nowhere to be seen – their floating nest visible some distance away. At this site there are two dams, the first closest to the road is higher in the catchment and I had spotted a well-advanced juvenile at the upper dam on my arrival. I’m wondering if the parents may have been there as well, overlooked as I passed – perhaps the tiny youngsters were the offspring of their most recent breeding effort.

Australasian Grebes nest, South German Track, 26th January 2012.

Whatever the situation I suspect the baby grebes were at great risk without the parents nearby – a Little Pied Cormorant was perched just overhead and while this species prefers yabbies, fish and frogs I suspect the unattended grebe chicks would have made a tasty morsel!

The alert and hungry cormorant.