Sunday 30 January 2022

Genoa Gorge

 I have long intended to visit the Genoa Gorge, firstly because the name sounds interesting and secondly because there are a heap of interesting birds seen in the immediate area that are not found elsewhere in the Mallacoota District.  The latter include Diamond Firetails, Yellow-tufted Honeyeaters  and Turquoise Parrots, both of which were seen on a recent visit to the general area (which didn't go to the Gorge itself).  With the weather of 29 January being relatively benign Frances and I headed off there.

The starting point is the turn off the Princes Highway about 1km North of Genoa, marked to Wangarabell, Wroxham and Nungatta.  Its about 10.5km along a well surfaced (but twisty) dirt road to the (un-named) track to the Gorge.  Google Earth is your friend.

EBird track marking function is your friend for showing the track to the gauging station.  This track was taken as we walked down.  Having done so, I'd rate the track as high-clearance 4WD only: and with VERY careful picking your way through the ruts.  (A concrete pipe is evident at one point with great potential to damage suspension.)  It is about 700m to the end of the road and drops (according to Google Earth) about 30 metres to the gauge shed. 
The start of the track is quite steeply downhill and the surface is very slippery in spots.  I removed  a little bark from arm and knee to validate that statement!
The density of the regenerating vegetation is evident in that image.  It made it rather difficult to see birds but there was a lot of vocalisation indicating they were around.  I suspect my list omits quite a few whose calls I didn't recognise.  Bird of the day was a clearly seen, but not photographed, dark-phase White-bellied Cuckooshrike.

The track ends at a shed housing some of the gear.  It is several metres (~15?) above the river.  This image was taken about halfway vertically between the shed and the water.  A handrail for a set of metal steps descending the final bit is just visible to the left of the tree trunk.  We went to the steps but not down them!  This looks like a granite sill .
There is a good flow in the river.
The BoM site (under River Conditions) shows the flow to be well under flood level.
Looking upstream shows the actual Gorge.


 

Sunday 23 January 2022

Some more walks

 The weather has been quite pleasant recently so we have been doing a few walks.  The first of these was a new one, along the Genoa River Fire Trail.  I had thought this was about 1km long, but we discovered this to be a fairly significant error.  My eBird tracker came up with 3.29 km  - one way!

This is the start of the track: the first of many undulations.
After seeing several in the bush as we drove to the start, our hope was to find some Dipodium roseum (Rosy Hyacinth Orchid) as we progressed.  It took a while, but we were successful eventually.
Comesperma sp was common along the trackside, and the flowers appeared to be still developing.
As always (except for the depths of Winter) Scaevola ramossissima was common.
The pontoon was in position at the end of the track.  (Mermaids' faces have been obfuscated to prevent identification.)
That was then.  The following day (22 January) we started with the Double Creek Nature Trail in the hope f finding a Painted Red-browed Treecreeper.  (I will have commented previously that any bird with Painted in its name is a pigment of someone's imagination.)
We began up the steps, on a principle of getting the pain over early.  There is massive regrowth evident here as in so much of the area, 
Much blossom on some of the gums - not game to even call the genus.
Beside the Creek the tree ferns are magnificent.  They deserve two images.

We then crossed Genoa Rd and strolled out to the Inlet, hoping for a Painted Striated Heron/Azure Kingfisher/Lewin's Rail.
None of the above obliged but it was a very pleasant walk, with only one boggy bit.



Thursday 6 January 2022

Weather of 6 January 2022

 For the last week the BoM forecast has been mentioning some rain over the 6th and 7th of January.  The amount suddenly jumped yesterday so I was not surprised to find 5mm had fallen into my weather station when I got up on the morning of the 6th.  

It has been raining fairly steadily (with a squall at 93 mm/hr just before 1100hrs).as at noon my WS is up to 24.8 mm for the day.  The Bairnsdale 256 km radar shows a reasonable amount more on the Northern horizon.

Bearing that in mind and hearing a few rumbles of thunder I checked the lightning tracker at www.blitzortung.org.  That shows a few strikes coming down the coast.  It also shows a LOT of strikes in the Riverina.
That led me to look at the 512 km radar.  From the direction the systems are tracking (green arrows) there is a lot more liquid heading in our direction.
I have found in the past that my weather station and the BoM sites for Mallacoota (at the Airport) and Gabo Island give fairly similar readings.  However for this event and that of 9-11 December 2021 there have been quite marked differences.
It would be interesting to compare the falls by time through the period, but unfortunately BoM use a strange format for time in Climate Data on line, chucks in readings in addition to the usual 30 minute observations, and together with the daft 9am reset means that I'd have to do too much work to get comparable data.  


To be continued.



Annual Weather report 2021

 Much of the commentary about weather will have been revealed already by the "year to date" charts as we have progressed through the toenail of 2021.  So I will try in what follows to present stuff in a slightly different way.  For those who wish to explore the data for other gems, I have loaded it to a Google Sheet.

The overall summary would be a wet, about average temperature, and calm year.

Rainfall

The 4th wettest year since 1975.  The fall of 211.8 mm was 146% of median annual fall and 137% of mean annual fall.
The data prior to 2019 is all from the BoM site close to the Airport.  I have compared the results for the last 3 years between the two sites and they are very close (within 10mm) for 2020 and 2021 but the airport recorded an extra 50 mm in 2019.  That was a very dry year at both sites and the difference appears to accumulate through a lot of events where the airport scored a few mm more, possibly reflecting storm cells moving along the coast.

Looking across the months, the  211.8 mm in December 2021 was the wettest December in the 45 month series.  With 145 mm August was the 3rd wettest while March and May were both ranked 4.  Only 3 months recorded below median rainfall.

Temperatures

The average temperature for the year (calculated as (avg daily min + avg daily max)/2) was 15.51C compared to 15.42 C for the long term average.  (Note that the long term value has been adjusted to allow for the BoM maximum being (on average) lower than the values recorded on my WS, as the latter has less exposure to the cooling sea breezes.  The next chart shows the difference in average temperature x month.
Looking at the components of the calculations nearly every minimum value was above average and nearly every maximum value was below average.  This is consistent with cloud cover preventing warming during the day, but also preventing back radiation cooling at night.    (It is of course always possible that my sea-breeze adjustment has overcompensated.)

Minimum temperatures

The term 'average' can include both mean and median.  For minimum temperatures according to my combined series there is effectively no difference between these indictors.  They are shown in the following chart together with the average 2021 daily minimum by month.  The 2021 series is very similar in shape to the average series charted above.
An annual time series of daily average minimum shows a upwards trend with a fairly good correlation coefficient (0.53).

Maximum temperature

Much the same story as with the minimum temperatures: long term mean and median almost identical for each month and the shape of the curve for 2021 very similar.  There is enough similarity in the graphs at this level to make me think that the adjustment process - which I have done separately for every month -  is not very far out of whack.  
The time series again shows an upwards trend, with an even higher value for R2 (0.63).  I'm sure someone from Institute of Public Affairs with a PhD in Inuit Studies (or some background of similar irrelevance) would argue the point!

Humidity

There is a fairly consistent pattern of humidity through the day.  Clearly a drop from the quite stable level overnight to mid afternoon then rising again.  Also clear that 2021 was damper than the other 2 years (especially 2019).
The 2 standard times match closely with the morning "drop-off" and the nadir of the pattern.  I charted the monthly averages recorded at my WS for the standard times for each year.

For the 0900 hrs set the three years show a similar pattern until October: I have no idea why they differ so much in November and December.
The chart for 1500 hrs humidity is all over the place, albeit within a fairly small range.  Possibly the most interesting aspect is the downhill side in the second half of 2019: no wonder the bush was dry by the end  of the year!

Wind

I looked at 2 measures of wind.  The average maximum gust per hour and the average daily wind run.
The two series are 99% correlated!  Winds were relatively calm at my WS in 2021.  The Airport is usually somewhat windier than home.
To put the average runs into context:
  • in "The Home of the Blizzard" Mawson comments about a day in which the wind averaged 90mph for 24 hrs.  That equates to a run of close to 3,500 kms.  He commented on the same period of the wind reaching 200 mph. 
  • Checking BoM climate data on line for Hogan Island - Bass Strait - gives average per month daily runs of 735 km [April] to 861 km [Sept].  
  • The same source gives an average daily run for September at Maatsukyer Island (south of Tasmania) of 971 km.
To compare the pattern across months I have calculated average daily run.  As expected 2021 was the calmest year and 2019 the windiest.
For comparative purposes and giving a much wider view, here is an ABC article covering BoM's national view of 2021.








Wednesday 5 January 2022

Mainly New Holland Honeyeaters

 On 5 January Frances drew my attention to a large gathering of New Holland Honeyeaters in our bird bath.  Her high count was 11 birds.  The mob had reduced in size at little (they were constantly moving between the bath and an Acacia behind it) by the time I got to see them, with my high count being 8.

My first photo (on the Julian Alps rule - an ordinary photo of a mountain range on day n is better than one of a blanket of clouds on day n+1) was taken through a double glazed and somewhat steamy window.

Going to a more distant door allowed some better images.
I lobve this one of three of them shouting at one another!
A Little Wattlebird came to see what the noise was about and chased everyone else away.
Some went to feed on the red-hot pokers.
Others preferred some cannas.  Note the tail pattern of the one doing an exit stage left.


Tuesday 4 January 2022

The Kite watcher

Anyone who has read the excellent book "The Kite Runner" will be unsurprised  by what is going on in Kabul at present and not feeling hopeful about the future of that country.  However this post is far more pleasant, and about birds not stick and paper structures.

The story sort of begins in 2020 when a pair of Whistling Kites were very noisy around some Angophora floribunda trees very near our house.  (Incidentally, that species of tree, after which our street is named, is only found, in Victoria in this area.)  Nothing came of that event and they went and bred elsewhere.  In mid-July 2021 Frances saw a bird fly in carrying a branch but we didn't spot any further activity.

On 21 August I noticed a Kite perched in a high and exposed position in the tree and took a photo.  On checking that I had the twig  front of the bird in focus (pity about the bird ...) 

... I noticed the second bird sitting to the right of the frame.  Taking another photo and the second bird was clearly on a nest!  As it was late in the day I have post-edited the exposure of this second image to give a better view of the bird on the nest.
Somewhat later I set up my telescope in the road to allow some friends on an exercise walk to view the birds through my telescope, while they caught their breath.  Initially the bird on the nest was eating something that had been brought in and after a while the other bird joined in and both fed.  (I didn't have my camera or my digiscoping adapter to capture this.)

This seems like an excellent opportunity to study a breeding episode and I intend to update this blog throughout the period.  The length of the period is a little unknown as I am assuming there are eggs in the nest but I don't know when they were first laid.  HANZAB gives the incubation period as at least 38 days.  There will then be about 5 weeks with nestlings!  My intention is to record interesting events and milestones in this post.

From Google Earth the nest is about 25 m horizontally from my observation post on our deck.  Taking an approximate sighting on the nest with a protractor and using the excellent interactive diagram in this site, I was able to calculate the nest as being ~20m above our lawn.

The first updates are from 22 August.
  • As a Kite flew in over our house it was harassed by a Masked Lapwing which I assume to be the non-brooding bird of the pair nested on the lawn of our neighbour on the side away from the Kites nest.  The lapwing nest is about 50 horizontal metres from the Kite's nest.  We foresee interesting times, and probably a lot of noise, when the Lapwing chicks hatch.
  • The Kites usually call as they leave or arrive at nest.
  • Late in the afternoon of 22 August I was getting in some washing and heard much vocalising from the area of the nest.  Then three kites flew out of the copse. One promptly went back to the nest while the other two grappled talons and tumbled, linked together down from ~30 m up to about 2 m above the ground. One returned to the vicinity of the nest, the other to a low branch: after 5 min the intruder flew off.
The wind was very strong throughout 24th August and the nest seemed empty for much of the day. The branch it is on was moving around considerably in the tempest and I wondered if it had been abandoned.  The wind was still strong on 25th  but when I checked at 0708 hrs an adult was locked in position: they must have had a good serve of dramamine!

The adults appeared to have nicked off again later on 25th so I consulted a raptor expert.  Their advice was:
"I couldn’t say or guess whether they have abandoned.  Eggs can take a fair bit of chilling (hot sun is more quickly fatal), but the other thing  is, a parent kite might not be very visible if hunkered down low in the nest and the tail is pointing away from the viewer.  Maybe one is on the nest more often than is apparent, depending  on how well you can see the nest and attending adult.  Or maybe the eggs have hatched and the chicks are big enough (downy and feathering) to be left alone for periods, and are hunkered down flat in bad weather.  I guess time will tell, and you might ascertain more when  the weather is better.  If the nest has failed, the adults will probably have another go soon."
I checked the nest at 0640 (just daylight, and cloudy, but far less windy than the previous 2 days) on 26 August.  Both birds were standing in the nest, apparently eating.  The lighter-coloured bird moved off to preen on a nearby branch while the other settled down in the nest.  On our way back from our walk (about 0810 an adult flew in towards the nest with a Masked Lapwing in hot pursuit.  At about 0920 I saw one adult fly in, and its talons were clearly empty.  It moved to the edge of the nest and appeared to regurgitate 'something' which the incubating bird appeared to eat.  I'm not sure if that is normal behaviour.  Around 1010 I was checking with telescope and the bird on the nest was eating something red and bloody.

On 28 August both birds seemed to spend some time in the nest, which wasn't being blown around as much as on previous days.  The Lapwing chicks had emerged and one of the adults flew up to the Kite nest to squawk at the occupants.

Around 1 September the Lapwing family walked away and were last seen on the far side of the road about 100m away.  Despite this added distance on 3 September I saw an adult Lapwing pursue a flying Kite with the situation being resolved by the Kite barrel rolling and showing its talons to the Lapwing, which decided discretion was the better idea.

The Kites had been spending more time visible on the nest with the better weather from 30 August to 3 September. On 4 September the wind was not noticeable but there was very steady rain.  When I first checked the nest I thought it was empty but then saw a head just visible beside a framing branch.
On 8 September there was a minor ruckus as a Pied Currawong appeared neat the nest.  It was driven away very promptly.

On 14 and 15 September the bird on the nest (or birds as I can't tell whether it is the same one all the time) seemed very restless, and doing a fair bit on structural maintenance on the next while sitting in it.  I didn't see them add any new twigs, but there seemed a fair bit of shifting existing material around.  They were also quite vocal: mainly quiet calls rather than the well known whistling call.

16 September was much the same as the previous 2 days.  It was interesting to note how much the sitting bird "sank into" the nest.  Even with my telescope focused on the nest it required careful looking to spot some tail feathers at one end and the crown just visible at the other.  It is now at least 26 days since I first noticed the occupied nest: from the information in HANZAB the chicks should hatch by 28 September. (As the birds are so obvious when flying in to the nest I am inclined to think we didn't miss much of the sitting period: but we did overlook the nest building, so who knows.)

The birds were very vocal on 22 September with the sitting bird calling about once a minute and answered by another nearby.  Then a second bird flew in, and they swapped positions, continuing to call.  A third bird then called from some distance away and both birds from the nesting pair took off - presumably to repel the potential intruder.

I don't know what was going on on 23 September.   The nest was vacated early in the morning and stayed vacant all day.  Still empty in the morning of 24 September.  I did see a Kite carry a stick into a different tree in the copse of Angophoras later in the morning.  Around 1018 (timestamp on photo) there was a prolonged aerial battle with a pair of Masked Lapwings.

For about 3 weeks after 24 September the nest remained empty but the Kites were still in the area.  On 12 or 13 October a bird was seen sitting in the old nest.  A second Kite flew in carrying prey and fed it to the sitting bird. Around 0630 on 15 October a bird flew in to the copse carrying a twiggy branch about 50 cm long.  After a pause away from the nest it flew up to the nest and passed the branch to the sitting bird, which stood up and commenced placing the branch in the structure of the nest.  I have no idea what is going on!

On 19 October at 0710 both birds were in the nest, with the lighter bird feeding on something dropped in the nest.

On 27 October both birds were standing in the nest feeding.  On 28th, 0600, one bird sitting in the nest the other perched on a branch next to the nest.

On 31 October I heard unusual calls coming from the nest which did not seem to be emanating from an adult.  In the morning of 1 November it was clearly not the adults calling and there seemed to be some downy feathers caught in the nest.  I think we have chicks.  

I am now totally uncertain about the previous comment.  On 17 December I clearly saw a chick in the nest and photographed it on 18 December.  On the information in HANZAB I don't think it would have been around on 1 November.  Here are the photos.

I commented to a neighbour that  thought it was going to be a while before the chick started standing on the edge of the nest and stretching its wings.  Of course as soon as I said that as soon as I got home I saw the wings being stretched!  I wasn't able to get a photo of that, but here are some of feeding time.  It is possibly significant in terms of development that the chick appeared to be ripping off bits of prey itself, as well as being fed by the olds.

The length of the chick can be gauged by this image.  It tail is well to the left of the diagonal branch in the foreground.

The chicks face is visible in the background.

On 21-22 December the chick seemed to be continuing its development.  It seems to try to feed itself, but still accepts morsels passed over by the parent.  When it stretched the wing (unfortunately not when I had my camera on it) it looked as though the primaries were getting some length to them.

On 28 December an adult was feeding in the nest as was the chick.  I watched briefly and saw no signs of flight by the chick.

By 30 December the chick seemed to have developed a fair set of flight feathers, but was staying in the inner side of the nest.  I am expecting the launch to come from the more open side, towards the paddock.

No further developments by 1600h on 31 December, but it was a very hot day (maximum at my weather station 37.3C).

The chick is still in the nest by the end of 3 January 2022.  It seemed to spend most of the day walking around the edge of the nest occasionally stretching its wings.  About 1730 it was standing at the Northern end of the nest when an adult flew in with some prey.  The chick got well shirtfronted, but both then fed.  The adult then left and the chick stretched again.  The flight feathers look pretty well developed.

We have kept a close eye on the nest since then (apart from when we were in Canberra)  and the chick seemed to spend a lot of time walking around the edge of the nest and stretching its wings.  Finally on 12 January I saw it out of the nest, perching on a branch.
Later in the day the nest appeared empty but there was a large bird moving around in another part of the copse of Angophoras.  I declare that the bird has fledged.  The process of shifting around in the nest tree has been described to me, by John Hutchinson, as a well known behaviour known as 'branching'.

The summary timeline of these events is as follows:
mid July:  Bird seen to carry branch in to copse;
21 August: 2 birds in/near well developed nest. 
22 August: defending territory.  Nest occupied constantly thereafter;
24 September: nest deserted for next 3 weeks;
12 October: nest seen to be re-occupied - possibly we missed seeing a couple of days (at least) of occupation as shown by counting back.;
9 -12 October: counting back using durations in HANZAB, eggs laid 
16 November counting back from chick feeding itself: hatching
17 December: chick's head seen in nest;
21 December chick appeared to feed itself 
12 January: fledged.

My final comment on this post is to note that on14 January the "chick" was seen flying and perching at a house about 150m down Angophora Drive.  So it has well and truly fledged!