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Precarious position

January 15, 2019

As described in the previous post, A wine glass half empty, it’s always a delight to come across an active bird’s nest, but things don’t always go to plan. We were surprised to find a flimsy nest in a spindly Drooping Sheoak (see below) out in the open at the back of our place. Further surprise came when we discovered a couple of downy chicks in the nest. These turned out to belong to a pair of Dusky Woodswallows, part of a small flock that had taken up residence here recently.
 

We were able to watch from a distance for a day or two as the parents regularly flew in to feed the chicks. But, perhaps inevitably given the precarious position of the nest and the number of predatory birds around – kookaburras, currawongs, butcherbirds and several raptors – the next visit to the site just a couple of days later revealed no sign of the nest, chicks or even adults – nothing!

It’s a tough world out there, and although our woodswallows got one stage further than Ronlit’s fantails, the result unfortunately was the same in the end.

See the slide show below for more pictures.
 

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A Wine Glass half empty

January 12, 2019

In fact this is a wine glass totally empty story. In the past few years I have been training myself to not just see birds but observe what they are doing and listen for them, because photographing them is one thing but being able to watch them nesting and rear chicks is another.

So it was with great delight before Xmas that I heard and then saw two Grey Fantails (Rhipidura albiscapa) involved in a lot of activity in the vines next to the house. The birds then started making repeated trips to the back door (pictured above left through an embarrassingly dirty window) where they appeared to be collecting the hairs of our Border Collie, Mac, from the door mat. The frequency of those visits suggested that the nest was not too far away and after careful observation of the to’s and fro’s of the birds the location of the nest site was soon apparent.

Over a period of five day the nest slowly took the shape of the classic wine glass (without the base), characteristic of Grey Fantails. Fantail nests are made of fine grass, bark strips, plant fibre (& Mac hairs) all held together with spider webs. Unfortunately, irrespective of what angle I tried to take a photograph (even from the roof) there were leaves in the way. But being aware of the danger of having the eggs predated by a currawong or some other bird I resisted the urge to do some pruning.

 
The literature says the sitting time is about two weeks. Through the three days of heavy downpours and the plus 40C days a bird sat on the nest (pictured above). Then after a week and a half, nothing. The nest was left untended and has been ever since. No explanation. Not even any evidence of eggs. All that is left is a deteriorating construction of bark and Mac hair, pictured left.

For a wine glass full story, a glimpse of what could have been, check out ‘A Grey Fan-tale.

Dollarbirds, cicadas and mynas

January 9, 2019

We received this report from Peter of Seymour about Dollarbirds beside the Goulburn River:

“On 2nd January, as I was walking along the river bank, I came across a loud gang of magpies and with it the call of a bird I didn’t immediately recognise. As I approached, the magpies flew off and a Dollarbird flew out of the trees above. Moving closer, I saw a Dollarbird chick on the ground (see photo above), presumably the target of the magpie gang. The chick had the plumage colour of the adults but a pale bill and gape. As I reached for the chick, I was treated to a wide-gaped threat and strident calls, with adults also calling nearby. I put the chick up into a branch and there it stayed – and was still there next morning. The adults were also around and both the adults and chick were calling.
 

I returned a couple of days later with Alan, a keen local birdwatcher, and we found the chick back on the ground but still apparently healthy. We then spotted a second chick at the entrance to a horizontal hollow branch high in a River Red Gum (see photos). Alan described how he had seen Dollarbirds nesting in similar hollows along the river in previous years. In particular, he spoke about the adults feeding the chicks with cicadas that are noisily abundant along the river in summer.

 
 
 
 
 
To confirm his observations, a Dollarbird landed on a branch with an insect in its beak and typical cicada wings protruding either side. Dollarbirds travel from Indonesia and New Guinea to Australia to breed over summer. At least in this area, cicadas seem to be a valuable food source and may be sufficient reason for Dollarbirds to travel so far south to breed.

Cicada exoskeletons

However, there is a sinister note to this story. Many Common Mynas were also present along the river bank. In an article on the Greengrocer Cicada in the December edition of the Victorian National Parks Association magazine Park Watch, John Kotsiaris notes that:
The other main threat to the green grocer, in my view, is the Indian [Common] myna bird; a very cunning and aggressive invasive species which was introduced into Melbourne in 1862 to control insects in market gardens. When male green grocer cicadas are attacked by a bird you will know about it. [The cicada] will let out a long, loud buzzing “eeeeeeeeeeeeeee!”. I have found that almost always [it] will be in the beak of an Indian myna.

So, the question is: are Common Mynas a threat to a critical food source for the breeding Dollarbirds? Or are there enough cicadas to go round?”

PS. As far as we are aware, the Dollarbird would be a rare sighting in the Flowerdale-Strath Creek area, and we would be pleased to hear from anyone who has seen one.

And babies make 31

January 7, 2019

I will never know the discomfort (or not) of carrying a child when the temperature outside tops 40C but I would imagine that I would be spending a lot of time inside under the air-conditioner whether it be at home, the library or shopping mall. Animals don’t have that option.

In the baking heat during a rest stop on a bike ride I spied this Australian Native Cockroach (Ellipsidion sp.) pictured left, spending time on the apparent search for something. Closer examination of the insect revealed it to be a female carrying an ootheca (egg case), the pale brown mass under the wings (pictured below).

The male and female cockroach mate end  to end.  The female then produces an ootheca that contains between 20 and 30 eggs, each egg being surrounded by air space. The oothecae when formed are soft but harden upon exposure to air. They are carried around until a suitable spot is found to deposit it, usually in a bark crevice. When hatched the instars look similar to the adult (pictured right) but without fully formed wings or genitalia. The life cycle proceeds through several instar stages until the final moult (ecdysis) when the adult emerges. The adult is initially white (pictured below left) but develops colouration over the space of several hours.

But at the start of this cycle spare a thought for the Mum wandering through the bush on those hot days with 30 eggs on board.

Jewel of denial

January 5, 2019

Jewel Beetle (Castiarina sexplagiata)

For those among you who have claimed never to have seen a Jewel Beetle in our district, have a look in the flowering plants at the moment. Early in the New Year is the time when Sweet Bursaria (Bursaria spinosa) flowers i.e. right now. The nectar-laden flowers seem to be a magnet for insects, in particular beetles.

A half hour survey of a stand of this plant recently yielded over two dozen beetle species. Among the most striking are the Flower Chafer group of beetles e.g. the Fiddler Beetle, and a group collectively known as Jewel Beetles (Buprestidae family) of which there are about 1200 known species in Australia.

Jewel Beetle (Castiarina sp.)


 
Most Jewel Beetles are daytime nectar feeders especially on Eucalyptus and Leptospermum (Teatree) species and of course Sweet Bursaria. Some feed on leaves. They are usually very colourful, hence their name. The larvae are wood borers in live trees. Jewel Beetles can sometimes appear numbering in the thousands.

There’s no denying it. There are a few around at the moment.

P.S. If you like your insects bright and shiny check out this previous post.

Q: Why do birds have down?

January 3, 2019
by

Birds are very well insulated. They have fluffy down feathers to trap body heat in when it is cold. One has just got to think about the warmth of a real down jacket or sleeping bag. But what happens to birds when it is hot? Last Christmas Day was very hot and the birds around the birdbath (pictured) were behaving in some peculiar ways.

Animals like humans have sweat glands in the skin. These glands produce moisture on the skin surface which evaporates, producing an evaporative cooling effect. Birds however do not have sweat glands and resort to a number of other methods to stay cool.

When it is hot birds, like dogs (which only have sweat glands in select parts of the body e.g. nose & feet), cool themselves by panting. An open mouth combined with an increase in the breathing frequency allows evaporative cooling to take place on the moist surfaces of the lungs and air sacs. The more rapid the breathing rate the greater the heat transfer. Through this process heat is lost from the body but so is moisture. Birds need to drink need to replace this moisture. Pictured above left is a Common Blackbird (Turdus merula) in a typical panting stance.

Birds can also shed heat by spreading their wings and promoting airflow in less feathered parts of their bodies such as this Willie Wagtail (Rhipidura leucophrys) pictured right . Anybody who has owned chickens will be familiar with this pose in hot weather.

And internally birds can control heat by redirecting blood flow away from areas such as the gut which produces metabolic heat (stopping eating has the same effect) to areas wear heat transfer to the surrounding air is easier e.g legs or combs in the case of chickens.

So the answer to the question posed in the title…

A: So they don’t fly too high…obviously.

Strike up the band…

January 1, 2019

…the fiddlers are in town. Fiddler Beetles (Eupoecila australasiae), pictured left, are so-called because of the violin-styled motif on the hard outer wing cases, and are also known as the Rose Chafers. They are members of the Scarab family of beetles of which there are over 2000 species in Australia. Scarabs are probably better known as one of the sacred symbols in Ancient Egypt.

Flower Chafers, of which the Fiddler Beetle is one species, are a sub-group of the scarab family. The word chafer comes from the Old High German word chevar meaning gnawer and beetles such as cockchafers are notorious for eating the roots of grasses, thus destroying lawns.

Most scarabs are nocturnal insects but the flower chafer group are daytime nectar feeders particularly on the flowers of Eucalyptus and Angophora and therefore are important pollinating species. They are also distinguished by flying with their outer wing-cases closed (most beetles open their outer wing-cases when flying). The pupae feed on decayed wood and emerge as adults in early summer.

At this time of the year a number of flower chafers are active including Punctate or Spotted Flower Chafer (Neorrhina punctatum), pictured right, and the Grey-furrowed Rose Chafer (Trichaulax philipsii), pictured below left, most notable because the grey furrows are actually densely packed hairs on the wing-case.


 
And this time of year would not be complete without a mention of the Christmas Scarab (Anoplognathus sp.) pictured below. Not a flower chafer, it is a nocturnal feeder causing the characteristic shredding of Eucalyptus leaves, a serious problem when beetle numbers get out of control.

It is so representative of my Christmases as a kid, it should wear a red cap with a white pom-pom.