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Why the long face?

April 17, 2021

A horse walks into a bar and the bar-tender says to him ‘Why the long face?’ This is one of the jokes I often use to liven up a party…NOT. But it does remind me of a grasshopper I have just observed whilst on my walk, a Giant Green Slantface (Acrida conica), pictured below.

Also known as the Long-headed Grasshopper, the Slantface is characterised by a conical shaped head and flat sword-shaped antennae. They come both with and without brown longitudinal stripes along the side of the body.

They are slow moving insects but have a number of defences that prevent them from easily being attacked by predators. The first is camouflage. In the grass on which it feeds it is very hard to detect, even if you know where it has flown. When in flight the grasshopper displays a red abdomen that serves as a warning to predators not to attack.

Like crickets, cockroaches and other related insects the Slantface lifecycle is one of incomplete metamorphosis i.e. the young instars look exactly like the adult (except they don’t have wings) and go through a series of moulting stages as they grow to big for their shells. Eventually the adult emerges and flies off.

Sort of like getting your P-plates in humans.

Follow the leader

April 9, 2021

Processionary caterpillars (Ochrogaster lunifer) are the larvae of Bag-shelter Moths. At this time of the year they can be found feeding mainly on acacias and grevilleas. As the name suggests the caterpillars shelter in a bag made of silk usually situated in or the base of a food tree.

When a given tree has been defoliated the caterpillars move to find another food source. The lead caterpillar leaves a physical trail in the form of a silken thread as well as a pheromone trail which successive caterpillars will follow head to tail in lines up to several hundred individuals. The picture below shows a procession of only a handful of individuals – I guess trying to walk up the bike path is asking for the silken thread to be periodically wiped out by passing cyclists. A processionary line is also formed when the caterpillars look for a suitable location to pupate (underground).

Both the caterpillars and the adults are covered in fine hairs. These are quite poisonous as they contain an anti-coagulant that can cause hives if touched. The fine hairs from the caterpillars are also suspected to cause premature abortion of the foals in horses.

Not everything fluffy is cute and cuddly!

A gulp of swallows

April 4, 2021

The title of this blog was going to be the punch-line until I looked up the collective noun for swallows and found out that it actually was gulp, as well as flight, herd, kettle, richness and swoop.

Swallows are widespread throughout Australia. Two species of swallows and two species of martins, also of the swallow family, occur in this district. Martins are distinguished from swallows by the square-shaped tail. Both swallows and martins are highly gregarious and are often seen in mixed flocks perched along fence lines (pictured below) in this case Welcome Swallows (Hirundo neoxena) and Tree Martins (Petrochelidon nigricans).

Welcome Swallows (blue head, brown face) and Tree Martins (grey)

Welcome Swallows (pictured left) are probably the best known of the group as they have adapted well to human habitation, frequently building its nest under the eaves of man-made structures. Tree Martins on the other hand nest in natural hollows that they line with grass and leaves. Both are acrobatic aerial feeders of insects, the martins at tree top level and the swallows lower down.

Also around at the moment are Dusky Woodswallows (Artamus cyanopterus), pictured right. They are also active insectivores. Named for their swallow-like tail Dusky Woodswallows are not actually members of the swallow family but are grouped with butcherbirds, currawongs and magpies.

Gulp!

As plain as black and white

March 30, 2021

A lot has been said about the LBJ’s (little brown jobs) – those hard to identify birds that flit around the treetops. At the moment I am having trouble identifying B&W’s (black and white) birds.

Willy Wagtail

It must have been a bumper breeding season for Willy Wagtails (Rhipidura leucophrys) this year. They seem to be everywhere. Wagtails are a type of fantail so called because of the habit of wagging their tails when foraging on the ground for insects. They aggressively protect their territory particularly nesting sites and will chase off much larger ‘chick-stealing’ birds such as magpies, currawongs and kookaburras. Wagtails inhabit most habitats except dense forests. At Flowerdale on our open-forested land I have never seen them on the property but will often see them on the boundary fence next to the neighbour’s open pasture.

Restless Flycatcher

The other black and white bird around at the moment that superficially looks the same as a Willie Wagtail but is more slender is the Restless Flycatcher (Myiagra inquieta). It is one of several flycatcher species in the district. The Restless Flycatcher is distinguished from other flycatchers by its white throat. Like the Willie Wagtail it is also an insectivore, the Flycatcher preferring to hunt mid-canopy, rarely on the ground.

Pictured side by side the differences are obvious. The Flycatcher lacks the black throat and white eyebrow of the Wagtail. They are more easily distinguished at a distance by their calls. The Willie Wagtail has the familiar ‘chittering’ sound whereas the Restless Flycatcher has an unusual ‘scissor-grinding’ sound.

Restless Flycatcher call (below)

Restless Flycatcher
Willy Wagtail

Discernment is sometimes in the ‘ear of the beholder’.

Next time, just a tickle

March 11, 2021

One thing I have noticed on my property is that Black Wattles (Acacia mearnsii) germinate as a group i.e. the seedlings all spring up at the same time. This obviously is a result of the conditions being right but it doesn’t happen every year. So I have clumps of wattles of different heights all growing and subsequently dying together.

Recently a grove has ‘taken off’ next to the dam. All the saplings had a dense head of foliage apart from one. It was denuded of leaves. Closer examination of the tree revealed half a dozen large caterpillars (pictured below) contentedly grazing on the foliage. My interest in caterpillars is directly proportional to how big they are. I therefore have found in the past Emperor Gum Moth (Opodiphthera eucalypti) caterpillars fascinating and these new examples were no exception.

The visitors were Golden Notodontid Moth caterpillars (Neola semiaurata). One would have that thought with all the decorations this caterpillar would have been easy to identify but for me it wasn’t. There are MANY species of moths. So I had to resort to a Facebook moth identification page (the wonders of social media!).

As I tend to have a non-disturbance policy when photographing fauna what I didn’t realise is that when disturbed the caterpillar rears its head back and a bright red protuberance (called an osmeterium) erupts from its throat. In addition, normally hidden under flaps of skin near the tail are bright blue eye-spots which the caterpillar displays when bothered. Sounds very photogenic.

I’m watching out for this caterpillar next year. I might give it a little tickle.

Small bird, big excitement

March 1, 2021

The Weebill (Smicrornis brevirostris), pictured left, is Australia’s smallest bird. The scientific name unsurprisingly comes from the Greek mikros meaning small and the Latin words brevis meaning short and rostrum meaning bill.

Weebills are found throughout mainland Australia, most commonly found in areas with dry, open eucalypt forests. They feed on insects primarily scale insects, psyllids and their lerp constructions. As such Weebills are usually found in the upper story of trees where the fresh new leaves and hence the sap-sucking insects are found. Around our district they are easily located in noisy mixed flocks, locally known as the ‘tribes’ as they scour the landscape for food.

The nest (pictured above) is pendant shaped with a hole in the side. It is constructed of grass and bark bound together with silk from spider webs and animal cocoons and animal hair. Nests are usually constructed in the canopy of trees. This one was found on an easily photographed flimsy branch just off the ground….

causing big excitement about the littlest of birds.

Hidden jewels

February 23, 2021
Castiarina sp.

Jewel Beetles are highly coloured and probably the most collectable of the insects, after tropical butterflies. The colour in each case is not an inherent feature of the insect but results from the diffraction of light from the insect surface (a similar process to how rainbows are formed). In butterflies the diffracting surfaces are the scales on the wings. For Jewel Beetles and other highly coloured beetles, pictured left, the colour is due to light being diffracted by small ridges on the exoskeleton.

Whilst weeding the lawn I came across a Jewel Beetle-ish looking beetle coloured black and white, pictured right. Upon closer examination it did the typical Jewel Beetle behaviour when threatened of retracting the antennae and legs and dropping to the ground revealing jewel-like colours underneath (pictured below). It is a Callitris Jewel Beetle (Diadoxus erythrurus). (Callitris is a genus of coniferous tree native to Australia and New Caledonia).

The adult Jewel Beetle lives for a relatively short time (days to weeks). Most of the lifecycle is spent in the larval stage. The larvae in this case bore into Callitris trees favouring dying or dead branches on otherwise-healthy trees.

A wise insect the Callitris Jewel Beetle keeps its treasures well hidden.

Not all dams are created equal

February 13, 2021

One would think that in any given area one dam would be much the same as another in terms of the existing biota. I am not sure it’s that simple.

In my neighbour’s dam at about this time of the year dusk signals the time for dragonfly nymphs to leave the water by climbing up the reeds and emerge as adult dragonflies. It is quite a remarkable spectacle. But in my dam, nothing. The only things ascending are myriad of mosquito bites on my arm as I sit fruitlessly watching for anything to emerge. Recently I travelled ‘over the hill’ to investigate someone else’s farm dam. To my surprise the reeds were populated by a type of spider I had never seen before, Long-jawed Spiders (Tetragnatha sp.), lots of them, pictured below.

Long-jawed spiders are elongated orb-weavers building small orb webs in vegetation bordering waterways. Their jaws are often more than half the size of their bodies. They eat arthropods trapped in their webs or capture by stalking them and are excellent at walking on the surface of water travelling faster on that surface than on land.

That’s all you need. A spider with extra large jaws that can walk quickly on land and water.

You wouldn’t put money on it

January 20, 2021

For experienced birdwatchers the metric by which to assess success is the number of species seen in a calendar year. If you have lived in a given area for any length of time this usually means counting the species that you have already seen in previous years. You wouldn’t put money on observing a ‘lifer’, a species you had never seen before.

I am not an experienced birdwatcher so there are still occasions when I see a lifer. Yesterday I heard a bird call (my time with the Murrindindi birders is paying off!) I had never heard before. Perched high in a eucalypt was a bird I had never seen – dark head with a deep blue sheen on its body. It was a Dollarbird (Eurystomus orientalis). The scientific name comes from the Greek eurustomos meaning wide mouth and orientalis meaning eastern.

Dollarbirds are members of the roller family so called because of their acrobatic courting and territorial aerial displays. The Dollarbird is the only roller found in Australia, its distribution stretching along the entire east coast and up into SE Asia, Korea and Japan. It comes to Australia in Spring and Summer to breed and then winters in New Guinea. Our area seems to be the limit of its southern migration. Juvenile birds have brown beaks and feet that turn bright orange on maturity. This species feeds on insects taken in flight and nests in tree hollows.

The term Dollarbird comes from the pale light-blue coin-shaped colouration that can be seen on their underwings when in flight.

That makes cents.

Slip, slidin’ away

November 6, 2020
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A neighbour of mine has a regular night-time routine – slug hunting. Rain, hail or shine she is out with a torch hoping to rid her garden of these pests. Slugs and their shelled cousins snails make up a class of animals known as Gastropods, creatures which have the same general characteristics, like:

  • Snails and slugs have two tentacles extending from the front of the head, pictured left. The upper two are the eye stalks. The lower pair contains ‘smell’ organs and is retractable.
  • These animals are hermaphroditic, having both male and female sex organs (I wonder how they decide which one to use!)
  • The snail shell keeps growing during the life of the snail. Calcium carbonate is added to the shell from the base that gets larger with time to accommodate the growing body. The shell spirals in a clockwise direction.
  • Snails and slugs have a single lung-like organ. The breathing hole known as the pneumostome is on the right side of the body and opens and closes as the animal breathes (pictured above). In snails the pneumostome is hard to see as the shell often obscures the view.
  • Snails and slugs have a series of microscopic teeth known as a radula with which they scrape lichen and other vegetative matter off surfaces.

Finally snails (not sure about slugs!) are delicious sautéed with parsley butter and garlic with a squeeze of lemon, and a glass of cold Chablis (I am not sure that applies to our garden snails).