Grass fire season

Landscape
The fire-scarred lower slopes of Castle Hill with,  in the distance, a patchwork of fire scars on the Town Common and near the airport

I have mentioned in earlier posts that our dry season is marked – marred, in fact – by a series of grass fires and the panoramic shot, above, taken on a recent visit to Castle Hill shows just how prevalent they are. The burning on the hill itself is obvious and I have circled fire traces on the outskirts of the city in blue – click on the photo to see them better.

The small black rectangles mark the locations of my bird photography on the Common last week, with the Pandanus viewing area on the left and the bird hide on the right.

What’s around – mid October

Still no rain* – at all** – and any area which doesn’t get watered by people is tinder dry or has already gone up in flames. People in one of our outer southern suburbs were under evacuation warning earlier this week but fortunately the threat was averted. We had a couple of days in the mid-thirties a couple of weeks ago, and then temperatures dropped again for a while but they are back up now and many of us suspect they are going to stay up – meaning daily highs of 32 – 36C and overnight lows around 20C. Humidity is up a little, too.

Hervey's Range Road
Hervey's Range Road, near the foot of the range: the undergrowth has been burnt out leaving the trees almost unharmed, and the grass will regrow with the first rain.

With all that, we are seeing a wider variety of insect life in the garden but not much increase in absolute numbers. Amongst the butterflies, Lemon Migrants, Ulysses, Orchard Swallowtail, Clearwing Swallowtail and Pale Triangle have joined Cairns Birdwings as frequent visitors, and all our recent residents – Chocolate Soldier, Crow and Eggfly – are still around (although still mostly male Eggfly; I have only seen one female). There are still Magpie Moths and the little grass moths, and a few more Hesperidae than we have been seeing.

Striped ichneumonid wasp
Ichneumonid wasp 1
White-tailed ichneumonid wasp
Ichneumonid wasp 2

Of the wasps and bees, the success stories are ichneumonid wasps, colourful mid-size to small critters with unpleasant baby-feeding habits, and my Blue-bum Bee, Amegilla. Of the flies, hover-flies still rule but there are lots of others as well; and I saw a Crane-fly pogo-ing around laying eggs in the soft dirt recently. Dragonflies have been returning intermittently and we have seen some of the smaller grasshopper species, a mating pair of giant grasshoppers, some ladybirds and a few shield bugs and pod-sucking bugs. Also, I’m less happy to report, a noticeable build-up of mozzie numbers. Oh well, the wonderful winter makes up for the less-wonderful summer.

I’ve been tracking spider numbers after a conversation with a southerner about the best time for a collecting trip up here in relation to our Wet/Dry seasons, and it’s looking tricky: we have had hardly any of the orb-weavers for a couple of months now but in the last few weeks I have been seeing lots of little ambush predators – Lynx and Flower Spiders (1, 2)in particular.

* What does ‘no rain’ look like on the map?

  • Qld July 1 – Sept 30 shows Townsville having had less than 25 mm in three months. (Compare it to the Jan 1 – March 31 map and you really see the Wet and the Dry.)
  • Qld September is even more impressive: Townsville is just on the edge of the white 0 – 1 mm area.

** Until after I finished writing the above. Let history record that on the evening of October 14, we had our first rain in six weeks and a pretty good thunderstorm. But I’m not going to rewrite my blog post!!

Dry season – fire season

Castle Hill viewed from the Common
Castle Hill from the Common

Looking back across the Town Common to Castle Hill I saw a plume of smoke rising from beyond its lower slopes. It was my second fire for the day, and a reminder that we are well into our dry season.

As the season advances, all the grass and other low growth that was so lush in the Wet dries out, dies and becomes fuel for any spark. We get a series of grass fires around the city – on Castle Hill itself, on Mount Stuart and its foothills, in road reserves and beside railway lines, and on private property. They are not usually much of a threat to life and property – most of them are quickly contained, and others in rough country can be allowed to burn themselves out – but they are always of some concern.

My first for the day was on Cape Pallarenda just a few hours earlier. I mentioned turning back from the Cape track to explore the Common, and the grass fire (below) which had started near the track not long before was the deciding factor. I considered walking around it, but the small risk seemed unnecessary with so many other places to explore. I didn’t hear any more about it, so I assume it didn’t do too much damage.

Grass fire on Cape Pallarenda
Grass fire on Cape Pallarenda