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Out of its usual range

November 18, 2018

The discovery of something that you have not seen before is cause for great excitement. Particularly when you are at home and think that you have probably seen all the birds, for example, that there are to be seen in the district. So excitement there was when a reported red, black and white bird (not a Robin) was observed in the uppermost branches of a local Melaleuca. And any unknown bird with striking colouration, i.e. red, is doubly exciting. On colours alone we guessed that it may have been a Mistletoebird.  But to be sure we had to call in technology in the form of a camera with a telephoto lens and a bird identification app on our iPads, in our case Pizzey and Knight. We also had to hope the bird was hanging around so that we could get another look at it.

The beak shape (pictured above) pointed us in the Honeyeater direction and the red coloured head narrowed it down to two suspects – the Red-headed Honeyeater, which is distributed along the northern coastline of Australia and unheard of in this area, or the Scarlet Honeyeater, distributed along the eastern seaboard and still uncommon here. Either way it was a bird neither of us had seen before (a ‘lifer’ in twitching terms) and outside its usual range. Geoff (Murrindindi Birdwatchers) and Macwake both confirmed the bird to be a male Scarlet Honeyeater (Myzomela sanguinolenta), a bird Macwake had documented in a blog this time last year.

The Scarlet Honeyeater is a seasonal migrant spending most of the year along the east coast between Sydney and Cooktown but migrating less commonly south of Sydney during summer. The scientific name is derived from the Greek muzao for suck, meli for honey and the Latin sanguinolentus meaning blood-red, i.e. a blood-red honeysucker, which is entirely appropriate given its food source is mainly nectar.

Adding a bird to the list is great, especially one so striking.

It’s all about hydraulics

November 14, 2018

The word hydraulics to me evokes pictures of pumps, valves and engineers – anything to do with liquids and water pressure. A little critter that wandered across my outdoor furniture setting recently is powered by hydraulics. You have probably all seen these tiny little spiders (pictured) which, with a mighty leap, suddenly disappear only to reappear many body-lengths away. They are aptly called Jumping Spiders and make up the family Salticidae which, numbering nearly 6000 species, is the largest family of spiders in the world.

Jumping Spiders are distinguished by their leaping motion which they use to hunt prey (usually small insects) or avoid being preyed upon. They do not have large back legs as does a grasshopper. The spring in its step comes from hydraulics, an explosive change in the ‘blood pressure’ in the back pairs of legs which rapidly extends them and sends the spider forward. The front two pairs of legs are used for grabbing prey.

jumping spider 1-DSCN9879The other obvious feature of jumping spiders is the rectangular shaped head into which four pairs of eyes are set in such a way (see photo above) as to afford the spider a 360 degree field of view. Jumping spiders have extremely good vision in both the visible and ultraviolet parts of the spectrum. Two of the eyes are much larger and face forward. They cannot rotate like the human eyeball. Instead the retina at the back of the eye can swivel to change the field of view. And hydraulics again, the focusing is done by manipulating the liquid in the eye structure to bend the light entering the eye.

Great jumping spiders, Batman!

How sweet it is

November 10, 2018

Spring is here and with it comes the growth of new sap-rich leaves, particularly on eucalypt trees. This means that it is time for the sap-sucking insects to put in an appearance. Insects of the order Hemiptera make up a diverse range of creatures all distinguished by having sucking mouth-parts. The adult and young insects feed by either sucking the sap from the leaves and stems of plants or sucking the juices out of other insects.

Sap-sucking insects such as psyllids extrude a sugary substance called honeydew which they fashion into ‘houses’ under which they live. These houses are called lerps. Lerps are in turn the primary food source for birds such as pardalotes and bell miners.

1-DSCN0101

Another sap-sucking insect around at the moment is the Gumtree Hopper (pictured above). Gumtree Hoppers also extrude honeydew which ants have found to be an energy-rich food source. If you look at the new growth on gum trees at the moment and you find it covered with ants, chances are the ants are ‘harvesting’ honeydew from the rear end of Gumtree Hoppers. The picture above shows an ant doing exactly that. The ant takes the honeydew back to the colony and stores it for later consumption. In return for this food the ants provide the hoppers with protection from predators and parasites.

If the ant is not there to collect the liquid it simply drops on the vegetation below (see picture above) to be collected by the ants at a later time. A tree supporting a large number of Gumtree Hoppers and their nymphs can become soaked in honeydew and have the sugary liquid literally dripping from the stems (pictured left). This in turn attracts bees which find the honeydew an attractive alternative to pollen.

How sweet it is.

Natural homes

November 4, 2018

Laughing Kookaburra

There have been many posts on this blog about nest boxes and their residents, both birds and mammals. The need for the artificial hollows that nest boxes represent is a result of widespread clearing of native vegetation for agriculture, and of particular concern is the loss of large old hollow-bearing trees.

Galah


So it is heartening, just lately, to come across birds that have been able to find suitable natural hollows in live old trees still standing around our district. The common feature in the pictures shown here is that the hollows are all in trees (Candlebark and Yellow Box) that are probably well over 100 years old, which is the minimum time it normally takes for useful hollows to develop. Without the equivalent of woodpeckers among our fauna, hollows in Australian trees are formed by fungi and insects, such as termites, and initiated by branch-fall or fire.

Candlebark (Eucalyptus rubida)


Striated Pardalote


 
 
 
 
 
 
 
 
 
 

The value of hollows to a great variety of wildlife highlights the importance of preserving and protecting old trees.
After all, surely an individual home crafted by nature is preferable to a box “made out of ticky-tacky which all look much the same”, as Pete Seeger sang!

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.