Some birds of the Botanic Gardens - in Canberra

Here are a few pictures of some of the birds which hang out at the Australian National Botanic Gardens in Canberra.

The White-winged Choughs of the Botanic Gardens are like the Silver Gulls and White Ibis of the Taronga Zoo in Sydney. They hang out around the public lawns around the restaurant, but they also live in the bush-like parts of the Gardens.

Chough family grooming themselves in the sun

This one was very busy walking (running) around.
Note the red eye, and the curved beak.
Ravens have white eyes and much heavier, straighter beaks.
This Chough was perched in a tree above the tables
and it was very busy preening itself.
You can see the white primary wing-feathers.
That is a feature or which they are named, but
which is not visible until they fly.
The other really obvious birds are these Wood Ducks.
The female looks tired, and when "junior" decided to go exploring
she sent Dad off to keep an eye on things.
The male bird was in fine plumage.
This shot makes it look as if my brother, Brendan has his foot on the head of the male bird.
Of course, he does not, but with the foreshortened image (of a zoom lens) it does look that way.
Here is the duckling (a single one, by the way, which means almost certainly, the local Ravens got the others in the clutch, when they were very much smaller.)
Very cute, but totally without fear - not a good attribute for a duckling!
When the Male Wood Duck decided that the little duckling
has strayed too close to Brendan it intervened.
It came between the duckling and Brendan.
It then hissed at him, with its neck stretched out.
Get the message?
Unmistakable, I would have thought.

Most unusually, throughout this little "charade", which we "set up" to see how close Brendan could get as a test (but a non-threatening one, I stress), the female Wood Duck did not move from her comfortable spot on the grass. That's why I say all this threatening body language was a charade, for it is normally the females who do the serious guarding of the ducklings. She knew junior was not in any danger, but Dad was on the baby-sitting roster - so he had to make it look good!

Happy Wattle Day

Today, 1 September, is Wattle Day in Australia.

I know Queenslanders and ex-Queenslanders will scream - "It should be 1 August". This issue came up at the Robertson Garden Club today, and so I decided to check it out. According to the Wattle Day Association, this issue was formally decided on an Australia-wide basis in 1992.
Here in the colder parts of NSW, many Wattles are flowering now. In fact, on my trip to Queensland last week, there were many Wattles in flower beside the roads. So the date seems appropriate.
Of course, as a former guide at the Australian National Botanic Gardens in Canberra I know that there are different species of Wattles (Acacias) which flower in each month of the year. But the reality is that the preponderance of the Wattles do flower in Spring.

Studies of buds of the Blackwood Wattle, (Acacia melanoxylon). The wattle blossom is clearly seen to be a composite flower, made up by many different flowers grouped into a rounded "head", dominated by a spray of anthers, each covered with pollen grains.
What one does not normally notice is the petals which rupture as the anthers mature, and push out to open. The botanists describe Wattle flowers and leaves in the following terms:

• Flowers actinomorphic; petals valvate, equal; stamens usually numerous, forming the conspicuous part of the inflorescence; leaves often bipinnately compound or reduced to phyllodes.

As for their actual flowering times, I have published photos of Wattles in flower in my yard, over the last month, and some others in the bush, near the Boxvale Track, on 12 July.

Here are several Wattle trees in full flower, visible from several hundred metres away. These are probably A. decurrens (amended from A mearnsii - 24.7.09 - DJW), the same ones as I have growing in my backyard. The flowering season, and brilliant golden colour is distinctive from other popular fern-leaved Wattles which grow in this district (as planted, non-endemic).For those interested in researching the world-wide distribution of "Wattles" or "Acacia" species - (the generic name "Acacia" has been subjected to review by taxonomists), Australia has some 993 formally defined species of 1381 species world wide number of species. That is 72 percent of all known species are found in Australia. More significantly we have 975 species (out of 987 species worldwide) in the sub-genus "Phyllodineae" the group of wattles which have flat "false leaves" or "Phyllodes", as distinct from the "true leaved" species - the so-called "fern-leaved wattles". Here is the leaf of one of the so-called fern-leafed Wattles, Acacia decurrens.

Below is a close-up of a Wattle phyllode - it is a flattened stem.
The lower image shows the "gland",
the shape and location of which is distinctive of each different species.

Australia has 98.8% of the world's "flat-leaved" Wattles.

Crimson Rosella in a Robertson backyard

The Crimson Rosella, Platycercus elegans is a common bird in Robertson. No question about it, but they are seldom as "open" in their feeding as this bird. Not only is the bird colour co-ordinated, with the Pineapple Sage (Salvia rutilans), the photo shows the bird actually feeding in their favourite way, crunching on the nectar-filled base of this red tubular flower.

I planted this plant at the back of the local Community Technology Centre, four years ago, just before the CTC opened (scroll down the volunteers page to see me in action!). I selected this plant in order to attract the Spinebills, our most common small Honeyeater. So I was surprised to spot this Rosella sitting there, low down in this bush, having a sweet treat (it has the sweet base of the flower in its beak). This plant is not Australian, it probably comes from Mexico (many Salvias do). Mexico is famous for its Hummingbirds which have evolved their long beaks and their hovering ability, to feed on tubular flowers (their favourites are red ones). Australia has many red, tubular, nectar-rich flowers, and we have our own specialist nectar-feeding birds - the Honeyeaters. Long thin beaks which they insert in the flowers. In return they receive a dob of pollen on their foreheads, which they take to the next flower. Thus they complete the nectar feeding-pollination cycle for the plants.

Juvenile Eastern Spinebill - note the long beak.

But our Rosellas have developed the ability to by-pass that pollination cycle. With their heavy, crushing beaks, these parrots are essentially seed eaters. However, many have developed a "sweet tooth", and crunch the base of the nectar-rich flower, to access the source of the sweetness. Unfortunately, for the plants, this totally defeats the plant's pollination strategy. I have previously illustrated the destruction of Waratah flowers by Rosellas.

My favourite image of Rosella feeding is this "head shot". It is severely cropped from a shot of a Rosella feeding in a Tree Fern in the Australian National Botanic Gardens in Canberra. In this case the bird is eating the fresh tips of the new growth on a Tree Fern.
I just love the colour balance in this photo. It is also a good shot of the detail of the strong, pearl-like beak and the coloured head. The blue cheek patch is distinctive of the Crimson Rosella, even in juvenile birds which are often green, or mostly green, causing confusion in inexperienced bird-watchers.

Spring Photo Competition - at the CTC@Robertson

Entries for the Robertson CTC's Spring Photo competition have closed (officially), but I guess we can squeeze in a few last minute entries if you feel inspired. But be quick!

I have entered one of the Gnome series shown a few days ago. And I have also entered a photo of a frond of a Soft Tree Fern (Dicksonia antarctica) unfurling. This photo was taken several days ago, at George's place. He has many Tree Ferns there, including both the two main local species - this one and the "Rough Tree Fern" (Cyathea australis).

The distinctive shape of the Tree Fern frond, as it grows, and unfurls progressively is really interesting. Historically they are called "crosiers" which is the name of a Bishop's symbolic staff - the so called "Shepherd's Crook" - named after the traditional staff used by shepherds, looking after their roaming flocks of sheep and/or goats. The hook in the top was supposed to help the Shepherd retrieve a lost sheep. All of that imagery has been borrowed by the Church as symbolic of Christ, the "Good Shepherd". And that is why the "crosier" is used for the symbol of power and authority of a Bishop.
But mathematicians and theoretical physicists have also focussed on the Fern Frond, as it unfurls, as a demonstration of "chaos theory" - for within each frond are smaller and smaller leaf sections, each of which as it grows, reveals the repetitive patterns which first prompted mathematicians to describe the seemingly endless repetitive sequences which are key to chaos theory. Obviously, in the Tree Ferns, these pattern repeats are not infinite, but the leaves are so large, and so complex in structure, that they are probably the supreme example in the plant world of complex leaf structures. The structure is described as multiple-pinnate, which literally means "feathered upon feathered" leaves.

There is an interesting description of this unfurling processes of Tree Fern branches in Wikipedia, where they describe it as "circinate vernation" - a term which is new to me.

I love these Tree Fern fronds, and I know that Crimson Rosellas also love them. They eat Tree Fern fronds, much as we humans eat Asparagus.
These photos were taken at the Australian National Botanic Gardens, Canberra, where they have a fantastic display of the Soft Tree Ferns growing in the rainforest gully. There is one point where the Tree Ferns are growing underneath a foot bridge, and one can often see Crimson Rosellas sitting in the Tree Ferns, chewing the young growth of the fern leaves, as in these photographs.

The Nature of more odd Australian plants

Hakea laurina - flower just opening
Following up on the earlier Blog about Grevillea flowers, I thought I would show you a photo of the supremely weird, wonderful and lovely Hakea laurina. For Leo's benefit, the entire "flower" is roughly the size of your beloved golf balls.

This plant starts out with a rounded bud, tightly encased in sheaths of a silky-covered papery substance. The sheaths fall off, as the "flower" opens. That reveals a tightly packed composite head of many hundreds of flowers.

Each flower has the same basic structure as the Grevilleas discussed yesterday. the main point of comparison is the dominant styles (white with green tips) which start out bent like a hairpin, but which, as they mature, open outward to form this "sea urchin like" flower.

In the photo above, the individual flowers on the right have matured, and the styles have all opened out. The ones in the centre are just opening, and the ones on the left are still developing.

Detail of Hakea laurina flowers

This shot (not as sharp as I would like, sorry), does at least show the intimate details of the flower structure. In the centre, you can see some flowers where the stigma has just opened out, leaving the four segments of the original outer casing of the flower still "exposed". Those dark pink patches are where the pollen is formed, before the style opens out, taking the pollen with it. It is not clear in this photo whether these particular flowers have any pollen on them, but that is how the mechanism is meant to work.

You can clearly see many flowers with the style still "in position" inside the flower "tube", before they open out. Some are just opening.

Grevilleas have a seed casing which is leathery, and which opens along one side, to release two seeds. They drop their seeds every year, generally. By contrast, Hakeas have a hard woody seed casing, which splits to release two papery winged seeds. But the seed casings might stay on the bush for many years, in anticipation of a fire, after which the seeds are released, to germinate on the freshly potash-enriched ash soil. Fire survival and fertiliser strategy, all in one.

The Nature of Grevillea Flowers

There are many "typical" forms of Grevillea flowers, and here I have just a few of them. These were taken at the Australian National Botanic Gardens, in Canberra, last week. I only had time for a quick trip around the place on an Electric Scooter, on a day out from hospital, so I just got a few photos. Sorry.

Even worse, I did not get to record the species names. Sorry, but I was being rushed.

Mostly these were flowers on shrubby Grevilleas, some quite small plants, others large shrubs. None of these were trees.

This is a "Toothbrush" form of Grevillea flower, just opening.

These flowers are individual flowers, grouped together in a composite structure (an "inflorescence"). If you look at the prominently visible, individual curved protuberances, each one is the "style" (the female part) of a single flower. It has burst open, after being curled up inside the original curled part of the flower.

At a rough guess, there are probably 50 individual flowers in this head of flowers.

This is a tightly formed "Cats Paw" form of Grevillea flower, from Grevillea alpina, I believe. All of these flowers are still unopened, and very tightly curled up.

It is at this point of time that the long styles (seen above) are tightly in contact with the male part of the flower (where the pollen is formed). When the flowers open, and the styles protrude, they come out dusted with pollen, which is then available to be collected by bees, or rubbed onto the heads of Honeyeaters, which come in search of the nectar which is found deep inside the flowers. At that freshly protruded stage (better seen in the Toothbrush" illustration above) the "style", while still dusted with pollen, is described as a "pollen presenter" - it is a female part of the flower, but it acts initially to present the pollen in a convenient location, to allow the pollen to be spread from flower to flower.

If you look closely (double click on the photo of the "Toothbrush" flower two photos up), look closely at the "styles" about 7 or 8 in from the right. They are very obviously "dusted in pollen". After several days, when the pollen is dispersed, or has dried up, the "style" then becomes mature, goes noticeably sticky on its end, and then acts in its true nature, as the female part of the flower, ready to collect the pollen from any passing bird or bee. This system of pollination is the same for the major members of the Proteaceae family, in Australia, the Waratahs, Hakeas, Banksias and Grevilleas. They are all closely related plants.

At left is a less common flower (inflorescence) form (amongst Grevilleas), where the flowers are displayed along the stem. The flowers are all in pairs, which is typical of all Grevilleas.

So, no matter what the form of the flower cluster, be it "Toothbrush", or "Cats Paw" or whatever, if you look closely into the composite flower structure, you will find pairs of flowers in all Grevilleas.

Possibly the largest of the Grevillea flowers, on the Grevillea robusta, (the tree is known as the "Silky Oak") is a "toothbrush" form of flower, but it flowers in summer, so I could not photograph it now. It is typical of a group of northern Australian Grevilleas, many of which are trees, not shrubs, and which tend to have yellow flowers.

The role of colour in pollination:

There is a theory that flowers which are bird pollinated are advantaged if they are brightly coloured, especially red coloured. (Butterflies appear to like yellow flowers, such as Everlasting Daisies.)

One group of Grevilleas which I missed out on getting a photograph of is the tiny little creamy- white flowered flowered forms. They are apparently insect pollinated. They generally have a sweet honey scent, but with such tiny flowers that birds cannot possibly pollinate them. The general theory is that they are pollinated by moths, which fits with them mostly being coloured white or cream (to aid the night vision of moths).

Certainly being coloured red or yellow is an advantage to those which are bird pollinated. However, there are some which are dull green and nearly invisible to the human eye, and yet the birds find them perfectly well. So, some theories break down, if you investigate them closely enough.

The Nature of Everlasting Memories

When Zoe and I went to the Botanic Gardens yesterday, I was scootering along the Main Path, when Zoe suddenly said: "Oh, look, - Grandma Flowers". And she was right.

We had come to an area where Everlasting Daisies were growing everywhere. My Mother, Zoe's Grandma, was an inveterate collector of dried flowers, for use in dried flower arrangements, and the Everlasting Daisies were her absolute favourites. The Garage was full of unused specimens, the house was full of little wall vases always with a few Everlastings in them.

Zoe remembers staying there on weekends, as a kid, and "helping" Grandma with her flower arrangements, which usually meant Zoe poking holes with her little fingers in the seemingly magic "Oasis" material which flower arrangers use. This stuff has a spongy texture, and, when dry it is nearly weightlessness. Of course, what Zoe didn't understand at the time, was that Oasis has its limits, and after enough poking with little fingers, it crumbles to a messy dust.

Still, Zoe loves these flowers, and to her they will always be "Grandma Flowers". So, they are a kind of Everlasting Memory for her. And I am pleased. My Mother, Nonie Wilson died on 18 March 2006, just a few days short of her 90th birthday. So this blog is for Zoe and for her.

The Nature of Patience

How can I complain if the Outreach Nurse doesn't arrive to take my blood samples till 11:30am? Well, I might feel like complaining that I have lost half the day. But what if the nurse on whom I was waiting, was busy helping someone who desperately needed admission to the Oncology Ward?

It makes my complains seem trivial, doesn't it?

I am still awaiting being released from the "system", and getting edgier and edgier. But Tough, Denis!

Here is a photo of a Bottlebrush - Callistemon sp. (species unrecorded by me) which I took at the Botanic Gardens (ANBG) in Canberra, several weeks ago. Leo told me that it is one of the few Australian flowers which he wished he could grow, but in wet, cold and soggy, Nova Scotia. that is a bit of an ask. My advice to him was that he ought concentrate on the wonderful plants he can grow there (as per my postings of several days ago). But such is the Nature of Gardeners, we strive to grow things which are beyond what is reasonable to try and grow in our own patches. Fortunately, for most Australian blog-readers, Callistemons are amongst the easiest of Australian plants to grow, and as the photo shows, some of the showiest.

This photo has served to cheer me up, you might be pleased to learn.

My favourite Tree trunks; and on village life.

OK, I know it is a bit weird to have favourite tree trunks, but bear with me.

The Botanic Gardens (ANBG) is housed within a natural forest, (see photo at left) of mixed Eucalyptus tree species. In simple terms they are smooth barked "gum" trees and rough barked, "stringybarks". They look completely different, but they are all related - part of a huge and varied genus of plants.

Please don't try and tie me up with the details of the species, (I am not a specialist). There are a many endemic (local, natually occurring) species on Black Mountain, the site of these Gardens, in Canberra. But in reality, the dominant species are probably only 4 or 5 in number. Over the last 57 years, hundreds of other Australian Eucalypt species have been plants throughout the Gardens (they were not officially opened till 1967 - see this link for the chronology of the Gardens).

But my favourite trees are the really old, gnarled natural trees, especially this huge old "Brittle Gum" - (Eucalyptus maculata).

It is about 20 metres tall, and close to 35 metres wide. To me, it is the treasure of the Gardens. And it is simply an old tree, growing where it always has done so.

This particular tree has been shaped by the forces of nature. It is also a favourite with kids, and its bark has been rubbed smooth, low down, where thousands of kids have "patted" this tree. I like that kids "relate" to Nature in this way. Technically, they are not allowed to, but the guides and explainers never really seem to manage to see it happening!

The tree's trunk has been been split, probably by lightning, at some stage after it had matured. This is not clearly visible in this photo - the damage is at the far side of the base of the trunk. but, the whole tree is out of balance, and it must have leaned over at some satage, till it propped itself up with its lower branches.

I would acknowledge that the tree has shaped and modified by "arborists" - in the interest of "public liability", etc, no doubt. In fact, they have removed most of those branches which were once propping up the tilted tree. But it is surviving well.But it beauty is entirely Natural.

Many of these trees have remarkable individual variation between them, in shape and colouration of bark.

When I was volunteering here, as a guide, I was frequently asked by North American visitors, (especially) why our trees were "naked". To people familiar with Pines, Elms, Oaks, etc they obviously seems that way.

In fact these smooth barked "gums" (and some of the related "Angopheras") shed their "outer bark" on an annual basis. The bark tends to fall away in smallish chunks, and the new bark (underneath) is often stained or coloured for a time (see next photo), before resuming the more normal white, silvery or pink colouration.

Here is another of my favourite trees - a classic tall, open specimen, in an area of lawn known as the Eucalypt Lawn. This area is very popular with visitors for summer picnics, and concerts are often held in this area, over the summer.

And now for something mischievous! I call this photo the "old man's pyjamas". Of course I have posted this photo upside down. The tree is growing normally. But the stained colour is completely natural.

Kindly allow me one little visual joke!

I decided to do this today, to allow my mind some relaxation from the Chemotherapy treatment I started this morning. Everything is fine, so far.

*****

Thanks for the emailed wishes of support, especially from my friends at Robertson. I really value that friendly aspect of the Nature Of Robertson. It is a small township, a village, really, but the size of the settlement allows people to get to know eachother, through casual meeting at the Supermarket, at the Newsagency, at Churches, or, my favourite meeting place, the CTC.

Our society has lost so much through the formation of huge, anonymous cities. I believe the scale of villages suits humans better.

The Choughs of the Botanic Gardens

Regular readers (and I do so hope you are all regular!) will realise that when in Canberra, I like to hang out at the Australian National Botanic Gardens (ANBG). I once was a Volunteer guide here, and those times were particularly happy for me. But when I left for Robertson I had to give up that service.

This autumn has been blessed with bluer than blue skies. There is not much else going on, in the world of birds, apart from lots and lots of White-winged Choughs (Corcorax melanorhamphos) scavenging for potato chips around Hudsons Cafe. And Crimson Rosellas, of course, but I shall leave them for another time.

These crazy Choughs look entirely black, until they spread their wings. When they are flying their two large wing patches are really obvious, and totally distinctive.

The other time they show their wing patches is when "displaying". Not only do they spread their wings wide, but they also do a weird thing with their eyes.

Their eye colour (the iris) is dark red as shown in Photo 3, (left). But they have pinkish skin around their eyes, and when displaying they somehow make their eyes bulge, and the skin around the eye gets enlarged, making the apparent eye size nearly treble the actual size of the eye. It is quite an effective display technique, even if it makes them appear stranger than normal to this human observer.

This behaviour is caught in one of my photos (below) but, as usual Geoffrey Dabb on the Canberra Ornithologists Group photo gallery has an excellent shot showing this display behaviour, complete with open beak, indicating the bird was clearly squarking, (as they do). My bird was stuffing its face, but still "displaying".

The Choughs of the Botanic Gardens have been particularly closely studied, possibly because their fondness for scraps of food from visitors to the Cafe makes them easy to observe. More likely it is because of their proximity to the Biology Department at the ANU.

In many respect they behave like "chooks", scratching around in the tan bark at the Gardens. But they are regarded as related to Crows and Ravens. They have many distinctive behavioural characterstics, such as "communal nesting", when 3 or more females lay eggs in the one nest, and a clan group collectively raise the young. The birds at the ANBG have been studied intensively, and many are banded with either colour bands, or, as in this photo, large numbered rings which are able to be read at a distance by field workers studying them.

Welcome to Squeaky Oscar

I have a brand new nephew, Oscar Alexander Finn. Actually I have a seemingly inexhaustable supply of nephews, but this one is precocious. He has his own blog site - at 9 days of age. Not bad going, Oscar! (tasteful photo courtesy of his blog site). Hope he does no have a team of copyright lawyers, already!

Have a look folks, at the hot-link above, and it is now linked in the side-bar as well! (the green writing on the side of the blog.) ("The Squeaky View")

Anyway, welcome to the world of blogging, Oscar, and welcome to the World, kid. You have a bright future ahead of you.

*****

Canberra continues to turn on brilliant autumn weather, and the deciduous trees are beautiful - not that I am taking any photographs of them. After all, the official raison d'etre is "The Nature of Robertson" and deciduous trees in Canberra do not qualify - on any basis.

I have been hanging out at the Australian National Botanic Gardens this week, and have enjoyed nice lunches there - today will Gillian. It was good to catch up with her. Gill was armed with photos of her new grandchildren. We appear to be in an age of grand-child breeding.

While at the Gardens, this week, I have also been tracking down several of those unusual plants which I commented about last week.

It turns out that one is Pomaderris glauca - the specific name means grey, or dusty, or something simlar. Certainly it has that grey appearance on its leaves. It was good to be able to see the plant "in the flesh" at the Gardens, and to be able to confirm the identification which was at best "probable" from the botanical descriptions and line drawings. Strangely, this species does not make it to the (otherwise wonderful) PlantNET site, but it is clearly described in Gwen Harden's Flora of NSW.

The other plant I saw last week, and photographed, is Eriostemon trachyphyllus (in the old books), now probably Philotheca trachyphyllus. The main identifying characteristic was, as I observed at the time, its size. It grows to a large shrub, almost a small tree. That alone makes it quite distinctive in that family of small to medium shrubs. This boring photo (at left) is just there to demonstrate that this plant has a definite "trunk". Technical photos are sometimes necessary, no matter how boring.

Other photos (not good ones, unfortunately) were displayed last week in the Bodalla State Forest blog.

*****

Incidentally, for those of you who understand these things, my brand new Macro Lens (actally a Nikon "Micro" lens) is back with the company for servicing, or replacement, as it would not "register" that the lens was connected, all the time. For the money I payed, that is not good enough!

It ought click into position positively, and be ready to work. I ought not have to hold the lens in a particular position, to make it work!. I do hope "Fletchers Fotographics" are reading this blog (and Maxwells, the Australian Agents for Nikon). After all, what's the point of running a blog, if you cannot give someone a hard time, occasionally?

I promise to thank them all, most humbly, in due course, when I hear that the problem has been solved! Smile for the Birdie! Click! :-))

Autumn evenings, and migratory Honeyeaters.

The wonderful cool freshness of Robertson evenings is seldom as comforting as in early Autumn.

Another comfort is Anni's blog, where she continues to intrigue us with the breadth of her imagination, and occasional clever photographs, such as today's self-portrait in a teaspoon (the photo is relevant to her story)

We have had a string of balmy days, with clear air, and temperatures in the high 20s, but dropping to the low teens, over night. Weather watchers could do worse than visit the "Mittagong Weather and Weather Cam" website. It is a weather statisticians dream.

My personal gauge of the changing of the seasons is the first sign of migratory Honeyeaters passing through. Yesterday I saw my first migrating Yellow-faced Honeyeaters (Lichenostomus chrysops) for the season. Today I saw a few more. There is no spectacular wave of migration with these birds, unlike images from Europe and North America of migrating Geese and other wildfowl.

These little birds drift to warmer climates, and to coastal feeding grounds, from their summer nesting grounds in the high country in southern NSW and Victoria. But they form small flocks, currently a mere handful of birds. They fly in small groups from one tall tree to another, in short distances of perhaps 200 metres at a time, then rest for a few minutes, then fly on. In a few weeks time, the numbers of birds in these groups will swell to 50 or maybe 100, and the frequency of the passage of these groups will also increase. Just because it is not a spectacular flight of passing birds, does not mean it is not a real migration.

I can tell these birds are migrating, quite simply, because they do not reside in the Yarrawa Brush over the summer. These Honeyeaters are birds of the tall Eucalypt forest, primarily. But they migrate to coastal heathlands, to arrive when the nectar-rich Banksias are coming into flower. So, over the summer I see none of these birds here in Robertson. But they pass through in autumn, and again pass through on their way back, in spring.

Incidentally, these birds do reside a mere 5 Kms away, on the sandstone based forests, down along the Belmore Falls Road. I am not saying that these migrating birds come from there, simply, just pointing out how specific their choice of habitat is. Belmore Falls, has sandstone-based scrubland and Eucalypt forests, with many proteaceous shrubs in the understory. That environment suits them as a breeding ground. The Yarrawa Brush, cool temperate rainforest country does not. The difference is primarily that our trees do not produce the kind of nectar supplies that these birds need. So they do not breed here. They fly through to get to other environments which suit them, for the autumn and winter seasons. Typically, that is the coastal heathlands of the NSW coast where many Banksias flower at the suitable time for them - autumn and winter. (Photo above is courtesy of the Macleay Valley Coast birdlist, on their Tourism website.)

Food sources is the limiting factor in this migration, by the way, not temperature. This is demonstrated by the fact that every year a small number of these Honeyeaters overwinter in the Australian National Botanic Gardens, in Canberra. Canberra has far colder winters than the Southern Highlands. But the Botanic Gardens has a cultivated collection of suitable food plants for these birds, with thousands of Grevilleas and Banksias, which flower over the autumn and winter seasons. So, a number of birds stay there, instead of migrating through to the coastal heathlands.