A few odd observations.

Last week I took a small group of bushwalkers (2 locals, and 2 American visitors) for a stroll along the Boxvale Track, near Welby (south-western edge of Mittagong), in the Southern Highlands of NSW.

The track is classed as an historic attraction, as it follows the line of an old railway line which was built to service the Box Vale Coal Mine which entered the coal seam halfway down the steep gully overlooking the Nattai Gorge. That way, they did not need to dig down through the overburden, but rather could cut straight into the open side of the coal seam (exposed by erosion of the hillside by the action of the river).

We were there to look for birds, which were moderately abundant.
I did not take any photos of birds on the day, as my task was more to listen and identify bird calls and then point out where the culprits might be seen.
Throughout this post, I will link to the Photo Gallery of the Canberra Ornithologists Group. The individual photographers are credited by that site. For the Rockwarbler, I have linked to the Birds in Backyards site, as it gives a full life history for that bird.

Some, such as White-throated Treecreepers and Fan-tailed Cuckoo were nice and obliging.

Black-faced Cuckoo-Shrikes perched high on Eucalypt Trees, and shuffled their wings, co-operatively. Rufous Whistlers were abundant. We heard Yellow-tailed Black Cockatoos in the distance, but they did not fly close to us, unfortunately.

We went up to the side of the old Water Reservoir (on the Nattai Creek). This is a good reservoir for water birds.
We saw:

• Australasian Grebes (several on floating nests)
  
• Pacific Black Duck
• Australian Wood Duck
• Little Pied Cormorant
• Great (Black) Cormorant
• Australasian Shoveller (a surprise for me)
• Royal Spoonbill in breeding plumage
• Eurasian Coot
• Dusky Moorhen
• Australian Reed-Warblers (calling profusely from the reeds beside us).

After we left the dam, we went up a steep part of the track (the railway line obviously crossed the creek on a very tall wooden bridge. The footings of the bridge posts are still visible.) As we walked up away form the creek we saw a bird which I was not expecting to find - a Rockwarbler, or Origma (image). I was provoked to lapse into the vernacular, and comment that these birds are "as rare as Rocking-horse Shit". In fact, the habitat is classic for this species, which is almost exclusively confined to "Sydney Sandstone" and adjacent limestone habitats. Normally if I see them, I expect it to be near the local waterfalls and cliffs, not just beside a walking track, even though we were close to the local sandstone creek gully. These birds are really fond of steep clifflines.

We continued along the track, which, as the train line crossed creeks or dips in the terrain, is raised some 5 metres above the surrounding natural strata. To get through the hilly ridges, the track was excavated through solid sandstone rock. The best example is the "Casuarina Cutting" which is nearly 10 metres deep, for a distance of over 250 metres. It is fascinating in this narrow cutting, to observe the tree roots which have been exposed by the excavation. Tree roots growing through rocks, following the water which penetrates along the natural crevices in the rocks.
In several places there were signs of previous fires, and the Lomatia silaifolia were flowering heavily, with their creamy white flowers. These plants tend to flower freely one season after a fire.
There are some magnificent old Scribbly Gums on the tracks in this area. Old trees with huge hollows, which must suit Owls, the Black Cockatoos and Possums. These are true "habitat trees" - whose continued existence is critical to the fauna of the region, as well as being old "seed trees".
Along the lower track which we followed back to the carpark, (we turned right, off the Forty Foot Falls track, after about 500 metres and went back parallel to the main track) there are many specimens of Persoonia glaucescens - the "Mittagong Geebung". It is always great to find an endemic species growing freely in the area after which it is named (Mittagong). This plant has a very localised distribution, and is listed on both Federal (EPBC Act) and State Threatened Species lists.

I thoroughly recommend the Boxvale Track walk, as there is always something interesting to see along this track - whether it be of historical interest, plants (it is especially good for Waratahs, in season), or for rare and/or uncommon birds.

Boxvale Track - Greenhoods, and other highlights

Today I went back to the Boxvale Track, near Welby, to check on the progress of some Nodding Greenhoods which I had seen in flower in early spring, two years ago.

I was in luck, fortunately, as they were just starting to flower.

I recalled that this colony is very dense, even though in terms of this species it is not a large colony. In fact there are two colonies, on opposite sides of the track. They are growing in a dark and very protected section of the track where there once was a "tramway" installed to remove coal from a coal mine further out in the Nattai Gorge (in the 1880s). Like all such tramways (or miners' train tracks) they were laid out as straight and as flat as possible. Consequently, the Boxvale Tranway was laid through cuttings in shallow hills, and along built-up mounds of earth and rock, in sections where the ground fell away too steeply for the tramway. In several creek crossings, there were even wooden bridges installed, and traces of that construction are still evident. Anyway, from the point of view of these Greenhoods, there is now a nice, cool, dark cutting about 4 metres deep through a sandstone hillside. Perfect for the Nodding Greenhood (Pterostylis nutans).

Here are two nicely matched flowers, growing like "bookends".
Another specimen was growing nice and tall, very much like the one illustrated in the PlantNET page for the species.Here you can see how close these plants sometimes grow, forming a carpet with their leaves. But only when conditions really suit them.Another interesting plant was a very narrow leaved form of Persoonia.It is almost certainly a natural hybrid between Persoonia levis, (of which there are some specimens growing nearby) and Persoonia linearis, which is the most common Persoonia here. This plants leaves were about the same size and shape as the leaves of a Callistemon citrinus. But it was definitely a Persoonia. The image is not great, but you can make out the fruit, which is diagnostic of the genus. The colour of the leaves, and texture resembled the P. levis parent, but the shape was far narrower, not the broad oval leaves of that species. But it was not at all like the P. linearis species (which has very narrow flat leaves). The bark was thick and reddish coloured, and flaky. In that regard it has the properties of both parent plants. The botanical texts acknowledge that such natural hybrids are not uncommon.

It is a shame that Persoonias are difficult to propagate, as a plant with these characteristics would have garden potential, if only one could successfully strike cuttings. But all the experts say it is virtually impossible to get them to strike.

On the way back to the car, I found several nice specimens of some small Mallee Eucalypts. You can see the multiple stems of this plant, instead of a single trunk, as with most Eucalypts. I have taken a photo of flower buds, and I hope to be able to work out what species it might be, later on. Such plants are recorded from the tops of the Blue Mountains (of which this area is the southern-most extension). And I have also seen similar plants along very exposed edges of the Shoalhaven Valley and Kangaroo Valley. In those cases, they are restricted to growing right on exposed cliff edges. here is was in deep sand, surrounded by tall Scribbly Gums.

Talking of which, here is very fine old specimen of a Scribbly Gum tree.The Boxvale Track goes out about 4 km to a lookout over the Nattai River Gorge, and from there one can take a track down to the river valley. Parts of this track are quite steep, and so there is a nice amateurish cliff warning sign. The point is evident. I should not mock the signwriter's skills, as indeed the valleys of the Blue Mountains and Shoalhaven are known for people slipping or falling over cliffs.I should report that along the way I saw old (finished) flowers of Acianthus (Mosquito Orchids) and many leaves of Chiloglottis (Ant Orchids) and also a form of Speculantha (Tiny Greenhoods - in the "parviflora" group) - with flowers now finished. Also I saw a single specimen of the Tall Greenhood (Bunochilus longifolius) in bud.

Musk Ducks - or were they Loch Ness Monsters?

Today I went to the Boxvale Track, near Welby (just south from Mittagong). I went looking for Orchids, as I know there are some spring-flowering Greenhoods there, but I thought I might find some others at this time of year. You never know till you look.

As it turned out I found few Orchids (none in flower), but lots of birds. For me the least expected birds were Musk Ducks. For that I must thank a delightful encounter with a fellow birdwatcher, who told me about the Musk Ducks up on a reservoir (which I did not know existed, even thought it is barely 50 metres metres from the Boxvale Track, behind a rocky outcrop). So, tipped off to look for them I went there, and sure enough, a male Musk Duck was there, displaying aggressively.

Male Muck Duck, beak held high in the air,
with the pouch under his beak clearly visible,
is doing his "splash display"

In typical Musk Duck fashion, this bird was making loud splashing noises (with its feet) and creating very obvious splashes of water, while circling out in the middle of the reservoir. (Musk Ducks are typically "deep water" ducks, as they dive for their food, not dabbling upside down, in shallow water, like many Ducks.)

A big double splash, and a very noisy one.

Anyway, after just a few minutes of this performance, the male had some success, for a female paddled very directly across the reservoir from the reed-bank on the far side of the reservoir.

Here she comes.
It looks as if she is pale grey coloured on the chest, but
it is a "bow wave" created by her swimming so fast.
She is in fact sitting very low in the water,
with head and back (only) out of the water. That is normal for Musk Ducks.

She then circled around the male several times, and then moved in close to him. She then seemed to disappear. The light was not very good, so it was hard for me to see exactly what was going on, but there was a lot of water disturbance, so I believe they mated.

I have seen Swans mating, and the process involved the female being virtually completely submerged. Muck Ducks swim very low in the water anyway, so it really was very hard to tell exactly what was going on.

Male visible, possibly mating with the female (not visible).
That is partly based upon the amount of water disturbance.
There is a lot of paddling going on out there!

But shortly after the "disturbance of the water", the female reappeared, and swam off by herself (to the right). The male is bending his head (and beak pouch) down (to the right), but his rear end is sitting very high in the water (unusually), and his stiff tail seems to be held past the upright. It seems that it is being fanned up over his back, in a rapid movement. At this stage, the male was making his extraordinarily penetrating shrill whistle call, interspersed by deep clunking noises.

If you did not know that you were looking at Musk Ducks, you could be forgiven for thinking you had seen a very small, Southern Highlands version of the Loch Ness Monster.