Random Snaps etc

 A few images from early April.  The first selection are from a bike ride to Bucklands and back.  A large Cormorant roosting in the big tree there turned out to be a Pied Cormorant.  It is very unusual to see that species there.

From a different angle the yellow facial skin is more obvious.

A young Nankeen Night Heron was lurking in the Pittosporum.  I wish I knew where they nested!

I called in at the bat colony which is massive, coming nearly to the bus stop about 150m from the little bridge over Mullet Creek.

I tried the video function on my camera and then used Clip Champ to reduce its size.  This is mainly to give an idea of the sound of the camp!  I hope it works!

Sunset looked rather good.

The bats were late leaving the camp.

Coming from the north?

 For reasons that escape me now I recently downloaded all the eBird data for Bega Valley Shire.  This is our immediate neighbour to the North but as it is in NSW eBird treats as though it is Siberia.  Having let that hobby-horse go for a canter round the paddock I will move on to the main thrust of this post which is to comment on whether a comparison of the species listed in the Bega set suggest some species which might turn up in East Gippsland sometime soon.

The simple comparison is easily done using the "find unmatched" query wizard in ACCESS, matching on Common Name.  This gave 123 mismatches.  Unfortunately: 

1. the Bega dataset was downloaded before the latest eBird taxonomy shuffle and the East Gippsland one after; and 
2. I hadn't corrected the spelling of Grey in the Bega set.

This meant that about 50 of the apparent mismatches were due to taxonomic/language issues rather the species not being in East Gippsland.  (This was exacerbated by some of the species being listed multiple times as subspecies - eg there are 3 listing for Gray Fantail and 3 for White-capped Albatross.)

A further 16 taxa were spuhs (eg "hawk sp.") and thus not really able to be considered further.  I can't imagine anybody twitching "Hawk sp." while "Pacific Baza" briefly got a lot of people checking their fuel tanks!

Of the 57 remaining mismatches 20 were birds mainly likely to be seen on a pelagic outing so I leave them to the specialists!

I have formed the remaining 37 taxa into two groups.  22 are species with very few records and thus will probably only appear in the Mallacoota District serendipitously.  The remaining 13 species may well - at first glance - have a critical mass in Bega to leak across the border.  These 13 are discussed in what follows in more or less taxonomic order.  Comments regarding the usual range (unless otherwise explained) are based on eyeballing a species map in eBird and the "number of records" is the number of eBird records in Bega Valley Shire.

Magpie Goose (6 records)

The usual range appears to be North of a line from the Illawarra to Cape Patterson.  Recent records near Canberra are just about on that line.  The species has records in Western East Gippsland at Lake Omeo.  The Canberra and Lake Omeo records are the closest to what are now regular sightings of two birds at Pambula.  Thus far in their history they have shown no inclination to make the 60km - as the Magpie Goose travels - trip to the Mallacoota District.

But I do look closely at the Genoa Flats every time we drive past.  A large and distinctive species, unlikely to be missed or misidentified.

Plumed Whistling Duck (3 records)

The Bega Valley records are from 2011 at Panboola Wetlands.  At that time there appeared to be an eruption from the species usual range including to near Canberra where a few birds are still seen regularly.  a few old records from near the Gippsland Lakes and Marlo.  I think the most likely source for this species is from the Canberra outpost.  The usual location near Canberra is a holding paddock at Bungendore where the main food for the ducks is grain which has passed through cattle.  

A large and distinctive species, unlikely to be missed or misidentified.

Red-necked Avocet 4 records

Bega Valley records at Lake Curalo, Eden in 2018.  The closest records to the North are Kiola Beach - about 200km in a straight line.  There have been several records, some of >100 birds in the Marlo area, so it could be hypothesised that any Mallacoota birds will come from the West.  I have seen the species in a wide range of habitats and would welcome comments from experts as to why there is a gap in the distribution from Marlo to near Kioloa.

A very distinctive species, unlikely to be missed or misidentified.

Lesser and Greater Sand-Plover 5 4 records

I am unfamiliar with either of these species (and it is messy with Lesser recently being splut (sic) into 2 species).  That gets a bit embarrassing with one of the records, of Siberian Sand-Plover, from Green Cape , being from me!  I think what must have happened was that I saw a Red-capped Plover but things got messy with no web coverage there and somehow the wrong species got selected.  I am very sure I didn't see this species there and then.

Both Greater and Siberian recorded along East and South Coasts, but sparsely in Bega Valley and  "on the corner".  I can't see why it isn't recorded in Mallacoota, other than it preferring unbirded areas such as Goodwin Sands.

There may well be confusion with non-breeding Double-banded Plovers so check closely.

Southern Giant Petrel 42 records

A pelagic species but with a good number of Bega Valley records.  This species is almost unrecorded between Eden and Phillip Island while there are a number of sightings of Northern Giant-Petrel in the area.  Referring to the Compact ABG this seems to reflect existing wisdom.  The crucial field mark appears to be red on the bill: a rather nuanced distinction for inexperienced shore-based sea watchers.

Not really coming from the North, but suggests careful checking - as far as possible - may pay off.

Glossy Ibis 9 records

The map in compact ABG suggests a definite absence from the SE corner which is not so clear from the eBird map, due to a few isolated sightings (mainly historical) at Pambula, the Snowy Flats and Gippsland Lakes.  The species seems to favour the major rivers of the Murray-Darling system and coastal areas North of (about) Nowra.  There has been a recent sighting at McLeod's Morass so the species can wander!

A large and distinctive species, not likely to be missed or misidentified.  Perhaps could be mistaken, with a poor sighting, as Straw-necked Ibis?

Barking Owl 11 records

Nearly all the records in Bega Valley come from reports (of a single bird?) by several members of a COG visit to Bittangabee Bay during a Green Cape camp so possibly there are only 2 records in Bega Valley.   Many of the more serious birders visiting Mallacoota include an owling event in their itinerary but no one has reported the species: given the distinctive (if out of Jack Russell territory) call this suggests the species is not here.  As the species is very sparsely reported East of the Hume Highway and South of Canberra (maps in both eBird and Birdata, and from description in HANZAB) I am not hopeful that it's range includes this area.

March Weather Report

 After flirting with a call of La Nina the BoM has reverted to a suggestion of neutral conditions for the near future, based on the usual analysis of ocean temperatures.  It is, of course, daft to compare current temperatures for a small area such as Mallacoota with climate drivers for a couple of oceans and a continent, but this dry warm/hot month is far more suggestive of El Nino.

Rainfall

What is this thing called rain?  A total of 35.6 mm for the month, with one large dew collection (0,2mm) on 31 March as the only contribution since 20 March.  Not surprisingly well below median fall and March 2023.

After a few heavy falls in January there has been very little rain so my pro rata estimates for the year have declined steadily.  The current pro-rata estimate for the year is 742mm (which would be the 4th lowest on record - but there is a long way to go).

Temperatures

Definitely an interesting month.  The temperature anomaly finished at +1.18C after getting what share-market analysts would call "bullish" - peak of +2.72C  - in the middle of the month.

The time series of anomaly values seems to show this month as part of a higher plateau, while the 12 month moving average continues to show an upwards trend.

The daily extremes show a very interesting pattern.  The earlier part of the month shows a very hot period, after some people were bewailing there not having been a Summer.  That was followed by the rest of the month being much milder in moving around the long term average for the date.

The immediately following material addresses to some extent both maxima and minima, so I have included it here rather than in the subsections below.  

I have recently posted giving some standard terminology I intend to use to cover extreme temperatures which I observe.  There were quite a few occurrences meeting the required criteria in March!  

• In the weather extremes chart above it is clear that the period from March 6 to 15 had consistently above mean minimum temperatures.  In that 10 day period 7 days had a minimum more than 1 SD above the mean, with 2 days more than 2 SDs above the mean.  For the month as a whole we added 2 more days more than 1 SD above the mean.
• The extensive period of hot minima was a little longer than that for maxima, where the extremes ran from the 5th to the 12th.  In that time we had 5 days greater than 2 SD above the mean.  There was 1 further day more than 1 SD above the mean.
• So  using my standard terminology we had:
• 13 warm days
• 6 hot days
• 2 warm spells lasting 7 and 3 days
• 1 heat wave lasting 4 days.  Had the minimum on 14 March been 0.4 higher we would have had 3 consecutive days with both measures more than 2 SD above the mean which I would define as an Extreme Heat Wave.

Balancing the heat (to a very limited extent) we also had 4 cool days with minima more than 1 SD below the long term average and 1 cold day with both minimum and maximum more than 1 SD below the long term average.

Minimum temperatures

The average minimum for the month was 15.27C, 1.06C above the average since 1994.  This year March was also a little warmer than last year.

For a time series I am using a plot of monthly values since I set up my weather station (WS) in 2019.  This shows 2024 as being in the upper part of the range, but not outstandingly so.

Reviewing the history of minimum temperatures those on the 9th and 10th were the 2 highest minima recorded in Mallacoota.  The 5 warmest minima in the month (all obviously >1SD above the mean) all fall in the 50 highest March minima (of 937 non-null records).  The minima on the 5th (rank 32nd) and 22nd (ranked 30th) were in the 50 lowest March minima.

Maximum Temperatures

The average maximum for the month was 24.7C, the second highest recorded and only 0.2C below the record.  Much above average and 2023.

Again looking at the traces from my WS this year is the warmest of the six years for which I have records. 

Reviewing the history of maximum temperatures (adjusted for earlier years to allow for the effect of sea breezes on the airport maxim in earlier years) the 35.1C recorded on the 10th was the second highest in March at Mallacoota.  The 4 warmest maxima in the month (all obviously >1SD above the mean) all fall in the 50 highest March minima (of 946 non-null records).  None of the maxima in the month  were in the 50 lowest March minima (the coolest day was only the 77th lowest maximum).

Humidity

The daily chart is almost a model of consistency in terms of the morning and afternoon reading relating to each other.

The morning (0900 hours) reading is a little above the average (since 2019) but below last year.  I find this a little surprising in view of the low rain.  I have looked for a relationship with wind direction and/or temperatures but couldn't identify any explanation that way!

More in line with my expectations, the afternoon reading was below the 6 year average and the value recorded in 2023.

Wind

Overall, more windy than March 2023 but a little below the average for March.

The daily runs show 2 outstandingly drafty days.  They are 5th and 8th in rank of March windruns (but slump to 40th and 55th if all months are examined).

More Bats

 On the evening of 8 February we noticed a very large flyout of Grey-headed Flying Foxes from the camp at Mullet Creek.  This was against a very overcast sky.  Movement was well underway when we first saw them at 1930 hours and continued until at least 2000 hours when it got too dark to see them from home.  

On the 9th it was too hot during the day to get out and about so we decided to walk down to Mullet Creek to see the flyout. We got there about 1925 hours and although we could see a few bats flying around in the trees but none heading across the Lake.  A White-bellied Sea-Eagle passed by but didn't show any interest in attacking the bats.

A few Pacific Black Ducks were paddling around in the Lake.

At 1941 hours -  at least 10 minutes later than the previous night - a few bats seemed to be getting in the air.  The sky was much clearer this evening.  The initial photos were taken from a small jetty, about 100m towards Karbeethong Jetty, looking across towards the mouth of Mullet Creek.

By 19:42:38 a good number of bats were in the air.

This was 19:47:40 which I think was the densest flyout.

This photo was taken looking more up the track to the Adobe apartments: the street light is just visible in the bottom right.

We left at 18:55:18.  The numbers in the air had dropped somewhat but it was getting quite dark.  There were still plenty of bats in the trees along Lakeside Drive: I don't think these would be babies, expecting them to be in the middle of the camp rather than the edge.

A zoomed view of part of this group.

Looking back as we headed for home at 19:58:26.

Looking from home it is difficult to pick the direction of the flight path.  From out position at water level this was more obvious and varied as the event progressed.  

We were standing at the point marked as Karbeethong Jetty (wrongly, the Jetty is about 200m upstream, marked as on Google Earth as houseboat hire).  The camp is marked - very approximately - with green lines.  At the start of the flyout the bats were going in the yellow direction which would take them towards Harrison's Channel.  By the time of the 19:47 image this had swung round to the blue line heading for Howe Flat, and just before we left it had move further to the pink line towards Fairhaven.

Compared to other nights we have watched from here they seemed to be going quite high.  Frances saw a few dip into the water to cool off but rather less than on other occasions.

I rode down to Mullet Creek on the morning of the 10th and took the following snaps to give an idea of the density of the camp at present.  Not every tree was this full, but many were.  I didn't go right into the camp, as whatever they fed on last night did not share properties with Imodium (they must have found some fig trees).

On the evening of the 10th I watched from the school bus parking lot, which gave a rather different feel to the occasion.

The first few appeared at 1948.

The horde was underway by 1953.

After a very hot day rather more were taking a dip to cool down.

On the 13th and 14th the weather was cooler and overcast in the evening.  On the 14th heading along Lakeside Drive Frances noted that the bats were in trees between the bus stop and the gate to the East of Mullet Creek, indicating that the camp was still increasing in size.  Coming back home around 1700 hours we noticed these 'extra' bats still present.  On both dates the flyout started much earlier (~1910 hours) and stayed lower, heading towards Fairhaven rather than the Howe.  On the morning of the 15th (~0515 hours) there were bat calls coming from the Angophora grove close to our house.  By 0630 they had moved on - presumably back to the camp.

On the 16th the weather had been very pleasant with much less cloud than other recent days.  I first noticed bats flying out at around 19:28.  They were flying very high.  The photos to follow were all taken from home.

The numbers in flight grew considerably.  

I have counted the bats in this image, putting a coloured dot beside each bat, and changing colours for each 100.  My total count is 561 bats.  Earlier in the season I counted 155 bats in a similar image: on the same day a scientist from DEECA did a more rigorous count (and estimated from the area of the camp) coming to 25,000 bats.  Applying the ratio of my two photo counts gives 

(25000 * 561)/155 = 90,484

As I am fairly sure that there were more bats flying below tree line by this time which were not counted and, compared to the time of the scientific count, more bats flying out the back to the Miners Track area, I am happy to say there are conservatively around 90,000 bats in the colony.  At the time of the scientific estimate I did a shonky estimate based on how long it took a bat to cross the camera field of view and duration of flyout arriving at ~15,000 bats.  Using that as the base I arrive at a current estimate of 55,000 in the camp.

I have not attempted to measure the total size of the camp but compared to the size it was when counted scientifically there are many more bats visible along Lakeside Drive and the extent along that road is longer than I ever recall seeing in the past.

By 1945 hours - light fading fast - many more bats were flying low to the water but they were still going out in good numbers.

The flyout on the 17th was pretty standard.  My only image shows the eucalypt - presumably bloodwood (Corymbia gummifera) ....

.. on the far side of Bottom Lake.

The weather on the 18th was ordinary, verging on average.  By 1900 hours it was very drizzly and the bats didn't flyout until about 1925 by which time the light was very poor.

By 1948 it was close to dark, but the bats were still flying out.  Unusually quite a number of them were coming over our house and I tried to get a photo as they came near the moon, shining through the clouds.  Failed

On 20 March the wind was very strong from the SW and the sky somewhat overcast.  Flyout didn't start until 1925 and most of the bats were flying low towards Fairhaven.  A few - many less than the previous evenings - were going high and heading towards Dead Finish.

The situation on March 21 was interesting to say the least.  The sky was clear after a relatively cold day, but flyout didn't start until 1925.  Numbers also seemed low and the bats were initially at least all flying low, towards Fairhaven. By 1940 a few were flying higher, towards Dead Finish, but a higher than usual proportion seemed to turning back towards the Miners Track.

A quite large flyout close to darkness on both 24th and 25th.  On the morning of 26th the bats were very noisy in the Angophoras near home from about 0600 onwards.  There were also a lot flying past, going back to the camp.  That seemed to have ended by about 0645.

On 27th Frances walked to Bucklands and noticed that there were many bats close to - possibly on branches hanging over - Lakeside Drive. 

She also commented that at Karbeethong Jetty the bats could not be heard, but assisted by a SW wind they could be smelt.  (We have recently noticed a faint smell on Angophora Drive early in the morning.)

On 31 March from about 1917 hours, when Frances noticed the first flyout, the whole sky is full of bats. Some crossing the Lake but a much higher than usual proportion heading towards the town area. I think the camp is still full. (I didn't get out until close to 1930 hours when it was too dark to take photographs.) The other end of this was a very large fly in past our house on 1 April until about 0645: there are often a few fly past, stopping for a feed and a squabble in the Angophoras, but this was several thousands.

The flyout on the evening of 4 April was unbelievable: the biggest I have ever seen.  Starting about 1910 looking out from our deck the entire sky was full of bats flying in all directions.  It seemed that many were heading out across the Lake and then turning back.  Very unusually, a modest proportion were overflying our roof: they usually go across the Lake (with the precise path varying between Lakeside Drive and the Narrows according to how they feel) or basically up/above the gullies of Mullet and Two Mile Creeks.  Still going at 1930 by when it was too dark to see.

On 23 April a researcher from DEECA counted the camp.  He first measured the extent of the camp (6.23Ha) and then counted the flyout: although they started after twilight a full moon was providing light and he thought his count of bats going across the Lake was good.  His estimate was 66,000 bats: this is 8-13% of the Australian population of the species.

28 April comment on FB: Still a lotta bats in the camp. BIG fly out starting about 1745 hours: many of them going out low over the Inlet then turning back and higher and towards Genoa Rd/Miners Track etc. An inspection earlier in the day suggested camp about the same area but possibly slightly less dense. On the 29th the bats were calling as they flew back over our house from about 0530. When daylight arrived ~0600 a few were visible flying back.