Plumes are in
I love the Spring Racing Carnival in Victoria. I am not interested in the horses but admit I do spend too much time watching the amazing sculptures that women wear on their heads. It’s fascinating. It’s also the time of the year that birds get into the headgear as well.
Breeding plumage is a term used to describe the changes to a males birds’ colour or form that occurs prior to the start of the breeding season. Differences between breeding and non-breeding features can include a change of beak colour and facial skin colour (Great Egret), change in the colour of the head plumage (Australasian Grebe) or the development of erectile ‘aigrette’ plumes over the back and on the chest like the Little Egret (Egretta garzetta), pictured above. Breeding plumage can also include head plumes.
Males birds like the Little Egret and the Nankeen Night Heron (Nycticorax caledonicus), pictured left grow two or three head plumes also known as ribbons prior to breeding season.
Not as flashy as the fascinators at the Melbourne Cup but sometimes less is more.
Keeping it clean
Everyone knows that the main job for adult birds is to keep their chicks fed. It is a never ending job.
A pair of White-throated Treecreepers (Cormobates leucophaea) has taken up residence in a local nest box. They are a small bird distributed along the east coast of Australia from Cooktown around to Adelaide. Treecreepers are insectivorous and often seen climbing up the trunks of trees looking for insects, mainly ants. At the moment the adults are busy feeding the young. Every one and a half to two minutes the parents leave the nest box only to return to the box bringing food (pictured left).
The other major task confronting adult birds is keeping the nest clean of the waste that the chicks generate. This is particularly true for birds that breed in enclosed nests. The chicks excrete a translucent gelatinous membrane containing all the excrement which the parent picks up and removes from the nest, pictured right. This appears to happen after every second feeding visit.
Of course if you live in an open nest like White-winged Choughs (Corcorax melanorhamphos) adults can save a lot of effort by teaching the young to poo over the side of the nest, pictured below.
Don’t call me Sugar
DNA analysis of the animal world is revolutionising how we classify them. Some species are being merged whilst others are being broken down into multiple species. The Sugar Glider (Petaurus breviceps), pictured below, the glider common in our area is a case in point.
Gliders are thought to have originated in New Guinea and crossed into Australia about 10 million years ago when low sea levels resulted in a land bridge between the two land masses. Until recently Sugar Gliders were thought to have been distributed from southern Queensland all the way down the east coast around to South Australia. They were introduced into Tasmania in the early 1830’s.
Recently (2020) however the single Sugar Glider species was divided into three species – Sugar, Savanna and Krefft’s Gliders.
What is now known as a Sugar Glider (P.breviceps) is distributed only in southern Queensland and NSW, east of the Great Dividing Range. The Savanna Glider (P.ariel) distributed across the top of Australia from northern Queensland to northern WA is named after the ecosystem in which it is found.
Lastly and more importantly for us because it is the glider in our locale is the Krefft’s Glider (P.notatus) distributed from Queensland to south eastern SA. The Krefft’s Glider was named after Gerard Krefft, a noted Australian zoologist in the 1800’s who was curator of the Australian Museum for 13 years.
So what we have previously called a Sugar Glider is now more correctly known as a Krefft’s Glider…. same packaging, different name.
Hot property
Almost half of Australia’s arboreal mammals and about 20% of our bird species live in tree hollows. Hollows however are at a premium. It takes about 80 years for a tree to develop hollows and a couple of hundred years for those hollows to become big enough to accommodate large fauna. Removal of old growth trees due to logging and agricultural clearing practices makes any remaining hollows hot property in the faunal real estate market.
Sometimes these hollows present short stay accommodation (click HERE to view). The nest box outside our house has had an annual revolving tenancy of White-throated Treecreepers, Ring-tailed Possums and Australian Owlet-nightjars for about ten years. But sometimes the hollows are more permanent homes.
In a local reserve a hollow in an old River Red Gum has been occupied by Brush-tailed Possums (Trichosurus vulpecula) for about five years. In the beginning it housed two possums, pictured left, although in summer the warmth obviously led the animals to let it all hang out. As the possums grew one moved out and the hollow was snugly occupied by a single possum, pictured right.
Last week however a Laughing Kookaburra (Dacelo novaeguineae), pictured left, took over the space.
With the shortage of hollows in the area no wonder it is laughing.
Good onya Mum II
The Masked Lapwing (Vanellus miles) otherwise known as the Clown Bird in this household because of its facial ‘mask’ (pictured left) is a raucous bird around these parts. Because of the unique design and structure of its nest it is a wonder, from an evolutionary stand-point that it is still around.
The Lapwing nest consists of a few sticks dropped on the ground in an apparently random fashion. Into this structure are laid 3 to 4 olive-green eggs which hatch in Spring. The nest is usually located in a clear open space and it’s a wonder they aren’t predated within a few days of laying. The parents aggressively guard the nest calling loudly or try to lead any potential predator away.
Famously eggs have been laid on the local cricket pitch (click HERE) and in the carpark of the recreation reserve, pictured left (there are three eggs laid between the wooden rail and the concrete slab. One of the parents looks on in the background). This season a pair of Lapwings decided to locate their nest in the fully fenced local swimming pool area that will not be opened again until mid-November. Maybe they are not so silly after all!
There appears to be only one chick this season that the parents also aggressively defend. If those tactics don’t work a shrill call from Mum sends the chick disappearing into Mum’s chest feathers (pictured below). Chick? What chick?
Good onya Mum.
Good onya Mum
One of the downsides of Spring is finding either broken birds eggs or bird chicks on the ground. On rare occasions (click HERE for the link) I have been able to successfully place the chicks back in the nest. But if you can’t locate the nest or even if you can but can’t access it what do you do? I try and move the chick from the ground to a tree or bush and then walk away and let nature take its course – hard to do if the chick is chirping loudly and the parents are responding in kind.
On Grand Final day I came across a Red Wattlebird (Anthochaera carunculata) chick, pictured left, sitting on the ground loudly chirping with two equally loud adults sitting above in the tree. The chick was in a fenced-off yard containing a single large eucalypt and a few bushes. No nest was in sight and the bolshie chick was not going to let anyone put it in the bushes. So I let it be.
Red Wattlebirds are the largest honeyeater on mainland Australia, its range extending across the south of the continent. They usually build a stick and bark nest in a eucalypt anywhere up to 15 m above the ground. The chicks usually fledge at two to three weeks.
Five days later I walked past the same yard and observed a parent (pictured above right) still feeding the much larger chick on the ground. I was pleasantly surprised to see the parents had stayed around to feed the chick and that a cat had not made a meal of it. On observing me the chick made a pretty good attempt at a take-off (pictured left).
I reckon give it another day or two and it will be able to fly out of harm’s way.
Good onya Mum for sticking around.
Just like a mozzie only fluffy
Australia has over 20,000 species of moths divided into about 90 families. Most of them look, well, moth-like. But if you look carefully as you are walking through the long grass at the moment you may see insects that look like mosquitoes at ground level flying out of your way. They may be mosquitoes but if they are fluffier then they are probably Plume Moths (Stangeia xerodes), pictured below.
Plume moths are of the family PTEROPHORIDAE, from the Greek pteron meaning feather and phoreo meaning to carry. In Australia there are 47 named (and many more unnamed) species. The wings are divided into lobes (usually 2 for the front wings and three for the rear wings) known are plumes because the fringing scales along the lobe margins are long giving the lobes a feathery appearance.
At rest the wings and the body present a ‘T’-shaped formation making the long legs and their spurs obvious.
So put the Mortein away. This is a good ‘un.
Legging it
Butterflies are insects. That means they have three body segments – the head, thorax and abdomen. At a more detailed level the thorax is comprised of three body segments fused together. To each of these is attached a pair of legs. The abdomen is made up of 10 segments. Young butterflies i.e. caterpillars also have a three-segmented thorax and a 10 segment abdomen.
The caterpillar pictured above shows this typical structure. Even though they may seem to have more, caterpillars only have three pairs of legs. As in the adult they are attached to the three thoracic segments near the head (see picture above). What appear to be legs further down the body are known as prolegs. These are hydraulically powered appendages used for gripping plant stems
Butterfly and moth caterpillars have a maximum of 5 pairs of prolegs. They are positioned on segments 3-6 and (always) 10 on the abdomen. The caterpillar pictured above has two pairs of prolegs which are characteristic of moths of the Geometridae family. The Emperor Gum Moth caterpillar (Opodiphthera eucalypti), pictured left has the full complement of five pairs of prolegs.
The number of prolegs is diagnostic for insect type. The larvae of sawflies (e.g. spitfires) have between 12 and 16 prolegs in addition to the 6 true legs. Scorpionfly caterpillars top the list with 18 prolegs.
It’s lucky they don’t have to buy shoes.
Large scale discovery
A recent early spring-clean of my kitchen unearthed the desiccated body of an Imperial Jezebel (Delias harpalyce) butterfly under a shelving unit. Given that these are on the scene during summer my spring-clean was obviously not early enough. It was also an opportunity to have a closer look.
The Imperial Jezebel (pictured left) is one of the more colourful butterflies in the district and is endemic to Australia being distributed along the coast and ranges of NSW and Victoria. The eggs are laid on mistletoe plants with cocoons being formed in early autumn and the adults emerging in the spring.
As with all butterflies and moths the wings are flattened membranous sacs covered in scales (pictured right). The scales provide the butterfly with both protection against the elements and thermal regulation. Scales are attached to individual slots on the wing in overlapping transverse rows and are easily detached, particularly useful if caught in a spider’s web! Marginal scales on the wing edges are longer and form a fringing effect (pictured below left). In addition the male butterflies have sex scales that are associated with pheromone producing glands.
The Imperial Jezebel males and females have different coloured wings. Scale colours are either due to pigmentation in the scale or diffraction of light from minute structures on the scale surface. In addition to colour difference based on gender this butterfly has different colouration due to season, there being a summer form and a spring form.
A wardrobe of a grand scale.
The third eye (lid)
Most creatures have two eye lids. They serve the purposes of a. opening so as to allow vision, b. spreading tears across the cornea so that it remains moist, and c. closing quickly so as to protect the cornea from damage from debris.
Many creatures also have a third eye lid called a nictitating membrane, from the Latin word ‘nictare’ meaning to ‘blink’, that wipes horizontally across the cornea. It serves as a protective layer from dust and debris for creatures such as Blue-tongued Lizards (Tiliqua scincoides) pictured, that live close to the ground. For water creatures such as rakali, the Australian water rat, the membrane is draw across the eye when it is swimming underwater.
The nictitating membrane can be translucent when its main purpose is being a ‘windscreen wiper’ or transparent when its purpose is to protect the cornea from the outside environment such as under water or for animals e.g. Peregrine Falcon that travel at high speed. Birds, fish, reptiles and some mammals have nictitating membranes. In humans the structure in the corner of the eye known as the semilunar fold is a vestige of a nictitating membrane.
I could use some when I’m on my bike!
Focus On Fauna 