A Damsel in Distress

As I knelt down to get closer to a wonderful chorus of breeding Moaning Frogs in a small Perth Hills wetland earlier tonight, I suddenly noticed the above Banded Orb-weaving Spider (Argiope trifasciata) right in front of my face! I was reaching for my camera when I heard a sudden fluttering sound and glanced back to see a damselfly (which may have been disturbed by my movement, or attracted to my head-torch), caught in the web. In seconds the ferocious female arachnid moved to seize her prey.

The Banded Orb-weaving Spider clutches one wing of her damselfly prey.

Within seconds the spider had hold of the damselfly and had dispatched it with a quick bite. I was amazed at how delicately she grasped its individual parts as she pulled it closer towards her body. The orb-weaver then began wrapping up her prey in a special multi-stranded 'glad wrap' silk (one of the many different types of silk spiders produce in their spinneret), for a later meal.

Meanwhile, the strong chorus of Moaning Frogs was continuing all around me. As always, nature presented an unexpected surprise that emphasised a small wetland can support a diversity of creatures, both the ones we see at a glance, and the ones which require a closer look.

Shell Story

I often say to people: "Keep an eye out for the indirect evidence of wildlife, and you will find a story to delight you and brighten each and every day!"

A good example of this evidence arose yesterday. While doing some weeding on the banks of my dam, I noticed a sign of a very special local animal known in the Noongar language as Booyi - the Oblong Turtle (Chelodina colliei). In the above photograph you can just make out the small, white shapes which are the remains of about a dozen (or maybe a Baker's Dozen!) eggs.

Fragments of Oblong Turtle eggs tell us a clutch was laid here nearly 12 months ago.

After a closer look at the fragments of eggshell, I could see these were evidence of the emergence from below the ground of some tiny Booyi hatchlings. How do we know they are turtle eggs? A process of elimination - no other egg-laying vertebrate would lay on or below the ground in this situation, or produce so many eggs (Oblong Turtles normally lay over 20), and few other local animals' eggs are so obviously white, except for birds. When compared to birds' eggs, which have a relatively thick and rigid shell, turtle eggs are much softer with a flexible shell, and after the young break out, the shells curl inwards and shrink.

So why were the eggshells on the surface and not below ground where they were buried? Perhaps when digging their way to the surface, the young turtles disturb the soil and the eggshells are gradually moved upwards. I know a Quenda (Isoodon obesulus) has frequently been digging in this area in the past few months, so maybe its foraging activities unearthed the nest. Of course there is also the possibility that the Quenda (or another predator like a Red Fox, Vulpes vulpes - a key threat to turtle nesting success) actually dug up and ate the contents of the turtle eggs. However, given that these omnivores normally leave a large spoil heap behind an area in which they have been digging, and there was no such evidence of this kind where I found the eggshells, I think these scenarios are less likely (I'm also being optimistic here about a successful breeding event!).

I have observed a female Booyi emerging to lay eggs in the bank of this dam only once before, over a decade ago, but found no evidence of the outcome. This time it was thrilling to think that somewhere out there, along the waterway that flows through my home, a new generation of these fabulous local native reptiles could be making their way in the world. Click here to view an image of a newly hatched Booyi.