Thursday, 27 June 2013

Tales of a Frog Pond

In some ways, I must have been a dream kid for my parents to raise. I brought home report cards filled with glowing praise and recommendations from teachers. I had an inbuilt respect for authority that more or less guided me to make the right decisions at any given time. I was good-natured with enough friends to easily fill out a birthday party, and I had a lot of interests. In fact, it wouldn't surprise me if my parents wished I had just a few less interests, or at least more "normal" ones. While other kids dragged their parents to Saturday morning sports games, I would make mine rise at 4:30am so that we could all get to the Mount Glorious rainforest in time for the sunrise. Sometimes we'd arrive so early that it would still actually be night time, and we'd have to wait in the car until the darkness turned to early morning grey. Then we'd begin to carefully navigate the forest trail - which we always had to ourselves. You might think this sounds like a wonderful family bonding experience, and it probably would have been if it weren't for the fact that I always insisted we walk in total silence so as not to spoil the chance of a wildlife sighting. Looking back on these trips as an adult makes me wonder if perhaps my parents didn't have things so easy after all.

Mt Glorious trip, circa 1994

The worst trips for Dad must have been the frog ones. On summer nights, just when he would have been wanting to kick back with a beer after a long day of truck-driving, I would appear with a torch and a pleading look on my face. If I was quick enough to beat the bottle-top snapping off that first beverage, there was a chance that twenty minutes later, we'd be wading around knee-deep in a dark swamp. I can't remember if building a frog pond in the garden was my idea or his, but either way, I think he must have relished the idea of my frog trips requiring no more than an un-supervised stroll down to the back fence for a change.

At the time, I thought the pond was a total success. About one-and-a-half metres long and a metre wide, it was a simple plastic-lined hole in the ground, with planks of wood supporting the sides and some gravel scattered on the bottom. Once it was filled with aquatic plants and water, we got in touch with a lady who bred and distributed tadpoles from her own pond and I started stocking mine up. Within a month, I had tiny Green Tree Frogs (Litoria caerulea), Graceful Tree Frogs (Litoria gracilenta) and Ornate Burrowing Frogs (Platyplectrum ornatum) covering the plants in the pond. Looking back, this might have been because they had nowhere else to go, as Dad's attempt to "landscape" the pond had resulted in us paving the area immediately surrounding it with bricks and a few of Mum's cacti in pots.

I loved watching the developments in my pond though. I'd see the tadpoles grow bigger and sprout legs. I'd examine the tiny froglets as they took on the recognisable colours of whatever species they were. I'd watch the plant life in the pond flourish, until one day I realised that it was flourishing just a little too well. Unbeknownst to me at the time, I'd selected the exotic Salvinia fern for my pond, and it was repopulating itself to the point where it had become a thick, dense mat. I became worried that the tadpoles wouldn't be able to break through that surface layer when they needed to become frogs, so I began to occasionally "thin out" the water weeds as part of my pond care routine. This eventually led to a wildlife encounter so horrifying, it has stayed fresh in my memory ever since.

On this one fateful day, I was bent over the pond on my hands and knees, scooping the excess weed out of the water when I noticed that there weren't any little froglets in the pond at all. Suddenly feeling alarmed that there was something wrong with my pond, I started blindly dipping my hand into the now murky depths, hoping to feel some tadpoles swimming around. What I felt instead was a solid, rough-textured object about the size of my hand, submerged under the water weed. I ran my fingers over it, wondering what it could be, when it moved! In fact, it didn't just move, it burst forth in a great leap, and there, splashing about in my beloved pond, was the biggest Cane Toad (Rhinella marinus) that I've ever seen in my entire life. It had eaten every single living creature within a two metre radius of itself. After that, I avoided the pond at all costs, so it was filled in and levelled off for Mum to add more cactus to.

Last year, when I decided to return to and base myself in Brisbane after many years of travelling, I felt compelled to revisit the idea of a frog pond. Best of all, after mentioning the idea to my Dad, it was he who kick-started the project by buying me the pond. Actually, to be accurate, he bought me a plastic sandpit in the shape of a clam shell, but you can see how it can be turned into a pond. After a month or two of procrastinating, I finally got around to digging a hole in the ground for it to be sunk into, as well as setting up the natural paraphernalia in and around it, like branches, gravel and bark chips. Planting two Mat-rush grasses either side of a Flax-Lily sealed the deal, and the pond was deemed ready to be filled with water.

September 2012

The first animals to find their way to it were the birds. Magpie-larks (Grallina cyanoleuca), Spotted Turtle-Doves (Streptopelia chinensis) and Torresian Crows (Corvus orru) were the most frequent visitors, with the Crows also using the water to soften up the flesh of dead animals they'd found elsewhere (ugh!). The bird visitors dropped off noticeably, however, when the vegetation around the pond grew higher. Perhaps they are too nervous to drink there now that their view of the surrounding area is somewhat diminished.

June 2013

Adding a potted Sedge and some aquatic plants has improved the water quality of the pond. I must have transported these plants from the gardening centre with some tiny stow-aways, as there is now a thriving population of Striated Pond-Snails (Pseudosuccinea columella) living in the water. I am grateful for this, as they eat and break down the leaves of the Moreton Bay Fig that occasionally float down from above.

Leaving the edge of the pond slightly elevated from the ground has made it harder for Cane Toads to hop into it, and only once have I had to fish one of the disgusting things out (don't tell my housemates). It has also allowed a family of Eastern Water Skinks (Eulamprus quoyii) to colonise the pond edges, as they can seek shelter beneath the rim at the approach of bird or man.

Originally, I had introduced the native Pacific Blue-eye fish (Pseudomugil signifer) into the pond, but I was battling with an algae problem at the time and the resulting poor oxygen level may have suffocated them. The algae problem was solved by submerging some water plants that have corrected the oxygen levels and visibility of the water. I will need to get the fish again in time for next summer, as they chow down on mosquito larvae but leave tadpoles unharmed.

As for the intended guests of the pond, a male Striped Marsh Frog (Limnodynastes peronii) made his way to and started calling from the pond on the Australia Day weekend of 2013. That was when ex-Tropical Cyclone Oswald ravaged Brisbane and dumped torrential rain onto our city for days on end. All that water must have relocated many varieties of animals, this individual included. I didn't see any sign of successful breeding activity during the summer just passed, but I did lay eyes on the frog himself one night, sitting quietly in the long grass next to the pond. Next summer, I hope he attracts a female to breed with there, and that the various Tree Frog species I've heard on my street get a look in on some pond action too.

This time, they won't have to live on bricks and cactus!

  • Dedicated to my Dad, Adrian Perrin, whose curiosity about the animal world sparked my own.

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