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Ducks and drakes

October 6, 2018

We spotted this handsome pair of ducks, pictured below, in a Strath Creek paddock this week. The following day there were six in the same area – three pairs that were squabbling and honking a bit, but were too far off to photograph.They are Australian Shelducks, still widely known as Mountain Ducks, although that seems to be a misnomer for a species that is found in lowland pastures and lakes.

Female


But perhaps no more of a misnomer than “shelduck”, which, according to Fraser and Gray’s Australian Bird Names, is from the obsolete English word “sheld” meaning pied. This refers to the European member of the shelduck genus Tadorna, which is primarily black and white. An earlier form of the common name for the genus was “Sheldrake”, which may have ruffled the feathers of a few feminist ducks!

Male


The same source attempts to shed some light on the name Mountain Duck. Apparently the term was used by early colonists of the Swan River and referred to “over the mountains” – the Darling Range presumably? Not sure we’re any the wiser, so perhaps we’ll stick with the official term Shelduck. The Australian part of the current moniker came about because it is the only endemic shelduck in Australia, and the name supersedes the former Chestnut-breasted Shelduck. So many confusing names!!

The shelducks’ distinctive calls can be heard by clicking on the audio bar below. This was recorded locally, and comprises mainly the female’s honks, but the male’s deeper response can be heard faintly in the background.

What’s all this carryin’ on?

October 1, 2018

 Insects play an important role in maintaining a clean environment and reducing the risk of disease by colonising and consuming carrion. Two important players in this process are carrion beetles and fly larvae and the race between the two for this food source is very competitive.

The strategy of carrion beetles of the sub-family Nicrophorinae is to get to the carcass first. They then attempt to bury the dead body before the flies can lay eggs on it. These beetles feed during the early stages of decomposition – fresh and bloated. Their very short lifecycle means that even if the carcass is fly-blown much of their larval development has happened before the maggots can dominate.

Carrion Beetles of the sub-family Silphinae beetles however have a longer lifecycle. They tend to feed on the later stages of decomposition – decayed and dry, after the maggots have had their fill. At the back of our property are the dry remains of a kangaroo, mainly just the bones and tail. The maggots have long gone. Crawling all over the carcass are the larvae of these carrion beetles (pictured). The Silphinae adults on the other hand also eat the fly maggots themselves.

A good rule when dealing with competitors – if you can’t beat them, eat them.

There’s a whole new world out there

September 18, 2018

Frogs have never been my forte. The variations in the colour and texture within a species can make identification difficult. And I never get to see them. Even the stealthiest approach to a dam turns the deafening frog chorus to silence. However with my new technique of using eye-shine to locate the critters at night I am coming across them all the time. This is particularly true after rain when they all seem to come out and sit on the driveway and are undisturbed by my approach.

The Pobblebonk or Eastern Banjo Frog (Limnodynastes dumerilii), pictured left, is easy to identify. The call, a loud “bonk’, is distinctive as is the pale stripe from below the eye to the top of the front leg.

A recent ‘find’ for me was a Spotted Marsh Frog (Limnodynastes tasmaniensis), pictured right, distinguished by the yellow stripe down the middle of the back (and the spots of course). I had never seen one before and I rushed back to the house with the photo only to find that they are distributed over most of Victoria and are very common. Still it’s good to find something I’ve not previously seen.

The identification that has still got me guessing is the frog pictured below. The pads on the toes identify it as a tree frog and distribution-wise either a Plains Brown Tree Frog or a Southern Brown Tree Frog. Because of the dark stripe from the nose through the eye to the arm I’m guessing the former. The difference in call is the frequency of the ‘cree cree cree’, not very helpful.

Rest assured I will be out at night when the next rain falls. There’s a whole new world of things to discover.

You are not alone

September 11, 2018

I have recently purchased a new LED head torch which is so bright I reckon it could scorch the fur off a koala at 1000 paces. Walking at night I can now locate arboreal mammals at a great distance by their reflective eye-shine.

In the eyeball there are structures that detect light called photoreceptors. In some animals there is a reflective layer situated behind these photoreceptors called a tapetum lucidum. Once light has passed through the receptors, this layer reflects the light back through the receptors therefore making ‘double use’ of the available light. This is particularly useful for nocturnal animals to make the best use of the low light levels. This reflected light gives rise to what is commonly known as ‘eye-shine’, light reflected from animal eyes at night.


When spotlighting at night, particularly with a head torch, the location of arboreal mammals high up in trees can easily be detected by the eye-shine. I have found that frogs can also be found by their eye-shine (though it is much smaller). After a recent rain shower Pobblebonk frogs (Limnodynastes dumerilii ) on the driveway (pictured above right) or tree frogs floating in the dam (pictured left) could be easily located. In fact sitting on the edge of the dam I could see pinpoints of reflected light throughout the reeds, even though the frogs were quiet in my presence.

But what stunned me the most walking back to the house was the hundreds of reflected points of light as I passed by the cutting on the drive. Closer examination showed that the rock wall was riddled with tiny holes not obvious during the day. Sitting in these holes were Wolf Spiders (family Lycosidae). I don’t know if their eye-shine is from the same mechanism but once I got my eye in these spiders were everywhere on the ground through the bush, even floating on the surface of the dam.

So get a head torch and look for yourself. If you see nothing it does not mean that there is nothing there. They just may not be looking at you.

A cool customer

September 3, 2018

This Black (or Swamp) Wallaby, Wallabia bicolor was browsing on the side of Moores Road, Flowerdale, the other day, at the junction with Broadford-Flowerdale Road, and was quite unperturbed by the cars whizzing by. That can be a problem if it suddenly decides the grass is greener on the other side of the road, and a number of wallabies have been killed by cars adjacent to Coonans Reserve which is a haven for these delightful creatures.

Wallabies in the bush are usually quite shy, bounding off noisily when confronted, and it is odd that some local wallabies seem oblivious to human proximity. Perhaps familiarity with cars breeds contempt. This particular wallaby did eventually hop off to the “cover” of long grass, but still seemed content to have its photo taken.

Unlike kangaroos, wallabies are generally solitary, but can be found in groups at prime feeding sites – for instance six were reported recently at the back of the Three Sisters property in Flowerdale. And like kangaroos, the males can indulge in quite hectic fights, which reminded us of an amazing video recorded by Rick and Claire at their property on the north side of the Yea Spur. It was posted on this blog in 2011 and can be viewed HERE.

Maybe the notch in our wallaby’s ear is the result of a similar fight?

Which is your favourite parrot?

August 29, 2018

Parrots are an order of birds characterised by a strong curved beak, an upright stance and strong legs. In Australia they include cockatoos, rosellas, budgies, corellas and lorikeets. They can be highly endearing. Generally they are brightly coloured and no one can help being amused by a flock of corellas swinging around on powerlines by their beaks or the jaunty crest atop a cockatoo.

HOWEVER… living in Flowerdale I am reminded of the (pre-bushfire) cedar house in the district that was covered in chicken wire to prevent the Sulphur-crested Cockatoos (Cacatua galerita) from ‘eating’ the entire house. At our place on Junction Hill the rubber seals on our windows and car windscreens have been destroyed by the same creatures.

Australian King-Parrots (Alisterus scapularis) are common along the eponymous creek in the district. As stunning as they are to look at, watching them snip off the seedling heads in our vegie patch as they did last Spring and then later raid the fruit of those plants which survived (pictured above left) takes the gloss off their presence.

Most recently Yellow-tailed Black Cockatoos (Calyptorhynchus funereus) have been around. Luckily their eerie cries warn you of their presence especially high in pine trees. With strong beaks they snip off the unripe cones (pictured right), take a few bites and then drop them to the ground from a great height. For the unwary these can do a bit of damage if the cones land on your head. A large part of their diet consists of insect larvae living under the bark of trees. In the quest for this food they can effectively ring-bark a tree, pictured left.

In the end I guess they are all doing what parrots do. Do I have a favourite? Not really. I regard them all equally. That’s parity.

Indeed quite parroty.

Tales from the woodpile #8

August 19, 2018

Winter is the season in which tales from the woodpile abound – who in their right mind would be rummaging through a woodpile in summer! This time the woodpile is not mine but Ken’s from Whanregarwen.

IMG_4897

The ‘Huntsman-looking’ spider is a Ground or Flat Spider (Hemicloea sp.). They live in leaf litter (or woodpiles) and hunt at night. Eggs are laid in large circular white disc sacs and are guarded by the female spider until they hatch. Ground Spiders are carnivorous and eat insects and other arthropods which they run down and attack with their large fangs (those glossy black things in the photo). The venom is not dangerous to humans.

Like most species which have appeared in the woodpile series, these spiders are broad and flat so that they can access the cracks and crevices in wood. They are almost two-dimensional – much like some of the characters in the news these days.