General observations about the local wildlife:
Destructive sampling – on the meaning of road kill
Strange bedfellows – goings on in a pile of grass
——————————————————————————————————————-Destructive sampling – November 2012
According to my workplace, there are all sorts of dangers that I need to be careful of. Stairs for example. Or going for a walk through the bush. Hmmm, really? But of all the everyday activities that most of us undertake, the most dangerous of all is driving into town. Someone behind the scenes obviously knows this, as travelling to and from work is no longer covered by workers’ compensation. But we are not the only species at risk from our massive addiction to the car.
In decreasing order, I reckon magpies, grey kangaroos, galahs, foxes and echidnas to be the most frequent victims of our haste to get there. And at this time of the year, turtles are particularly vulnerable, as are snakes and lizards stimulated by warmer days and amorous thoughts. There are many other victims too, but often they are unrecognizable smears on the bitumen as we flash by.
I have always thought that ravens had excellent road sense. They spend a lot of time on roads, helpfully cleaning up the carrion that we provide. Their smartness is evident in the way they eye off an oncoming car and casually hop away in the right direction just in time to avoid their demise, whilst maximizing their time at the carcass. Alas, our drive this morning revealed that ravens are not invincible. We passed two bodies on the bitumen, their black feather still gleaming in the morning sun. Perhaps these two were parents raising young, and the lure of just one more beakful of protein had marred their judgement. Or they were just unlucky.
At least birds and mammals have a reasonable chance of seeing cars coming and avoiding them. But reptiles, poor buggers are just not adapted to viewing objects over large distances. Most of them have about as much chance of avoiding a vehicle as the earth has of dodging a meteor. Late spring is reptile season on the roads. Warmed by the sun, they are on the move, seeking food, mates, places to breed. Some make the mistake of pausing on the bitumen to warm up a bit, not a good idea.
I find it exceptionally sad that these newly-emerged reptiles, pictures of glossy perfection, are squashed so regularly under tyres as they innocently go about their business. I generally try and note what direction they are going in, stop (or exhort the driver to do so) and move the slow moving shingle-backs or shoo the bearded dragons on their way. My most tragic lizard experience was in central Australia. Here, everyone wants to see a thorny devil, the most spectacular lizard of all. Late one afternoon, driving to Uluru, lo and behold, a thorny devil crossing the road. Hooray! We would see one up close! We screeched to a halt and ran back to it. Just a few steps from snatching it to safety … and the car following us ran it over. My only experience now of a thorny devil is that of holding one of these magical creatures as its eyes dimmed and it expired in my hand.
When it comes to turtles, there is considerably more caution about giving them assistance. No matter how carefully you pick them up, their defence glands can spray a most objectionable substance up to a metre, and this odour of fear ends up offending you, the car and any other passengers. Yet turtles suffer the most, as their shell often protects them enough to be maimed rather than killed outright, with a slow death ahead of them. Snakes don’t do too well either, mainly getting squashed in the middle.
For some reason I feel particularly bad about snakes, the same thought runs through my mind each time I see one killed on the road: “That was a waste of a perfectly good snake”. I think I feel more protective about them as I have a sneaking suspicion that the death of every snake I see might not have been as accidental as I would like to think. I suspect not many people know about the hazard of running over snakes; didn’t you know they can get thrown up into the body of the car, only to emerge later to bite you?
Of course, the only thing worse than having road kill is not having road kill. Inadvertently, our fast driving has become a method of sampling the fauna in the district. As a scientist, you sample something to estimate the amount of it. For example I might count plants in a small area and estimate the total number over a larger area, or I might dig them up to measure their total size. The digging method would be called destructive sampling. Though not an approach that an animal ethics committee would approve, destructive ‘sampling’ of fauna by our cars provides evidence that at least there are populations of animals to run over. Just try not to do it.
Strange bedfellows – December 2013
One of the more enduring reminders of land degradation on Gang Gang is a salinity-affected area low in the landscape, where the soil is salt scalded. Past erosion control earthworks and plantings of exotic grasses from over 20 years ago have not been entirely successful, due to unwise grazing. It is a mostly bare and weedy wasteland, and has become a recipient of any spare biomass that has been cut around the house in the interests of bushfire safety and vegetation management.
Over the years, small and large piles of grass have contributed to the improvement of the saline soil and plant cover is starting to return. One extra large pile of grass clippings had been vaguely designated as a place where we might get a potato crop, but meanwhile, something interesting has cropped up.
A year or two ago, we noticed some holes in the big grass pile, sometimes taking the form of tunnels and sometime collapsing out of disuse. Hmmm, curious, we thought, without planning to excavate them. Sometimes it is nice for nature’s mysterious aspect to remain just that. A mystery.
More recently, due to a birthday, I became the owner of a still image camera that detects motion by day and infra-red at night, so that while we laze around inside the house, we can now get records of creatures about the place. The locations that you can set up these cameras is limited, as foliage moving in the wind is enough to set them off and you can accidentally take thousands of pictures of slightly moving foliage, and not much else. However, the big grass pile seemed like a good candidate for surveillance.
We saw quite a variety of things sometimes in very quick succession, and not all associated with the tunnels. There were wood duck, a regular fox patrol, a black poodle, a stumpy-tail lizard, grey kangaroos and the odd human adding grass to the pile. The originators of the tunnels appeared to be echidnas, going in there for a cosy rest apparently in ones and twos. Although one photo catches three spiny footballs circling around in a night time mating train.
The story that the camera reveals is somewhat sketchy, sometimes the images are like a jerky movie showing the echidnas go into their hole or walking away. Sometime they just appear or disappear without a trail of images. In mid-October, we retrieved images of a red-bellied black snake – basking outside the echidnas’ hole for 25 minutes then retreating when the sun went behind a cloud. Not quite warm enough it seems. A pattern of morning emergence, 20-40 minutes of warming up, and then moving off became apparent as spring progressed. We had no images of he /she returning after moving off – perhaps they return at night and the snake is not warm enough to trigger the infra-red detector.
A patchy set of images suggested, but did not prove, that the echidnas and snake were co-habiting. But the images taken in October provided the smoking gun. On the 22nd, an echidna went to bed a 4.30 pm. The next morning, at 8.20 it left. Half an hour later a black snake emerged from the same hole. I wonder if they were snuggled up together, or had arranged separate chambers?
We were even more amazed by images two days later. The black snakes basks at the entrance for 20 minutes before moving off at 8.00 am. Two hours later, a brown snake emerges from the same entrance and makes a quick exit. But the black snakes seem to have the upper hand – that was the only brown recorded and, a week later, two black snakes are seen exiting right.
While I had not given any thought to the social life of echidnas or snakes, this has certainly got me wondering. Is there a housing shortage which means that they have to put up with each other? Probably.
Another source of wonder is the fact that the grass pile is on a well beaten track used by Jon and I. While all this busy social life has been going on, Jon and I did not once see a snake in the vicinity. They certainly are a very discreet animal. Or we are very unobservant, which is lucky for everyone really.