Tristaniopsis laurina

“A small spreading tree usually 4-10m high with handsome foliage and distinctive pale bare sheeny bark” - NPOS p. 371

The water gum is a common tree found on the east coat of Australia from the Brisbane River in Queensland through NSW down to Gippsland region of Victoria. It flowers in summer with groups of small yellow flowers with 5 rounded petals.

Flowering Water Gum in the wet. Flowers are said to have a strong smell but my nose couldn’t detect much

I’ve recently updated the Sydney temperature, sea level and rainfall pages to include the latest data available from the BOM. In case you’ve not seen these before a quick explanation: The BOM provides long term weather observations for the Observatory Hill weather station going back as far as 1859. It’s an amazing resource, when graphed over time you start to see some cool trends emerge. I’ve set it up so you can graph the raw observations or select to see moving averages from 6 months up to 30 years. For the shorter time periods the observations can be all over the place, even the 10 year averages fluctuate up and down but selecting the 30 year averages show clear trends. Except for rainfall! In Sydney at least it’s all over the place with no clear trend over the last 160 years, there are 10yr or so patterns that i think correspond to El Nino and La Nina events. Anyway, go check them out Sydney Temperature Sydney Sea Level Sydney Rainfall

While running in the rain I came across this group of sawfly larvae moving together en masse in the middle of the trail. I’m glad I spotted them, a misplaced foot could really have ruined their day!

This group of Steel Blue Sawfly Larvae was wriggling its way across a wet bush trail

I’ve seen these guys before, they are commonly known as spitfires due to their habit of regurgitating a thick yellow irritating fluid when they feel threatened. I stopped to take a few photos while my running partner caught up. She was a bit grossed out but fascinated too. I touched a few of them, they are soft and squishy, the hairs on their body are nowhere near as spiky as they look. When I got too close they would all start raising their tails and thumping them back to the ground, it was quite a sight! We said our goodbyes and left them where we found them, I hope they got where they were going to safely. See my previous post on Sawfly Larvae for more info.

Saturday morning after the hazard reduction burn. The smoke was choking, PM2.5 levels were close to 1000 µg/m3 for 4hrs

After last years terrible fire season I got interested in particulate matter air pollution from smoke and other sources and It’s effect on health. Inspired by this post I ended up buying some parts so that I could put together my own PM2.5 and PM10 detector. There are plenty of ready made detectors you can buy but I figured if I made my own I’d be able to customise it and add functionality that you’d normally have to pay a premium for. It’s also a lot of fun to build these projects and learn along the way! Last Friday there was a planned hazard reduction burn in our area carried out by NSW RFS, Fire and Rescue NSW and the NSW National Parks and Wildlife Service. We got some advance warning from a friend in the RFS so were expecting it. This would be the first proper test of my PM detector! The core of the detector is an old Raspberry Pi2. For the actual pollution measurement I used a SDS011 particulate matter detector. I also had a tiny little OLED display left over from another project that was used for a simple screen. I wrote some Python code to read the pollution values from the detector, display them on the screen and also post them to an online data recording platform. Initially I used code from the the raspberrypi.org post to read values from the detector. It worked but it was simplistic. It had the detector and the fan running around the clock even though I was only taking a reading every 5 minutes. After learning that the SDS011 has a limited operational life of 8000 hours I decided to take a different approach. By issuing commands to the detector it’s possible to only switch it on when making a reading and then switch it off again. The SDS011 is a popular part and there were already several Python libraries out there that handled the low level details, perfect! I went with Ivan Kalchev’s py-sds011 Running the detector, screen and Python code required some setup and configuration of the Raspberry Pi, I automated this using Ansible so the details would be saved and could then quickly be rerun again as needed. Here’s what I did OK, back to the fire. The burn was over a 33ha area of nearby bushland with the closest point only 2 streets away. As it started on the Friday morning huge plumes of smoke appeared, for most of the day air quality at our house actually was fine. All the smoke went straight up into the sky. At around 5pm that changed.

Grey Goshawks are a frequent visitor to the area, up until now I’ve not been able to identify or get a good photo of one. Last week I heard the sound of a screeching flock of cockatoos off in the distance, as they got closer the sound got louder. They were swooping and swerving making a huge racket, in front of them was a hawk! It looked like they were chasing it away! A few days later I spotted it sitting in a tree out the back and managed to get these photos.

The Echidna, such an iconic Australian animal and unique too being one of only two monotremes, the other being the Platypus. We’re lucky enough to have Echidnas in the local area and even venturing into our yard from time to time. Last week I was looking out the window at home while making lunch and noticed what looked like an unusual rough clump on the ground. I went outside to have a look and it turned out to be a group of four Echidnas huddled together in the sun! They were not moving and appeared to be just relaxing. I’ve only seen lone Echidnas before, four in one place was amazing!

There’s no shortage of sandstone in the Sydney area, almost the entire extent of Garigal National Park sits on what’s known as the Hawkesbury Sandstone. The Sydney 1:100 000 Geological Sheet classifies it as “Medium to course-grained quartz sandstone, very minor shale and laminite lenses” I wanted to highlight two sandstone formations, both of which are a bit of a mystery as to how they form. I came across these formations on a trail run on a section of single track in Belrose that runs from the end of Ralston Ave down to the Bare Creek trail next to Bare Creek. The first formation is called tessellated pavement.

In the bush nearby you can often see sections of sandstone that have clusters of regular sized holes around 10mm in diameter. Sometimes these pieces of sandstone are on a walking track where they get worn down to show the internal paths these holes take. I have a distant hazy memory of being told the holes are made by native bees. A bit of the old web searching brought up some more information!

It was over a year ago that I first saw this flying insect that had caught a large spider and was dragging it off somewhere presumably to eat. I’d never seen anything like it and I spent a while researching to try and work out what it was. At the time I thought it was a robber fly but now I think it’s a spider wasp! Robber flys do indeed prey on some spiders and other insects but the images really dont look anything like what I’d seen. The spider wasp is a much closer match. I’ve seen a few now, here’s some pictures of a smaller spider wasp with another decent sized spider. This particular one was struggling a bit with it’s prey. It even tried to fly a bit and only just managed it. Looking at the picture the spider could easily weigh more than the wasp! Spider wasps are known to chop off the legs of the spider to make it easier to carry. All the ones I’ve seen the spiders are missing their legs. Nature is brutal!