Update on Bats and Weather

I have republished this post to get it up the list as it summarises observations of theflights out.

Bats

I posted recently about the Grey-headed Flying Fox camp at Mullet Creek.  We have been watching the flyout each evening since that post was published.  Here is an update on the situation.

• 23 February: Cool day.  Very large flyout from the camp for about 10 minutes mainly heading towards Captains Creek.
• 24 February: Warm Day.  Very large flyout from the camp for about 10 minutes.  About 50% headed to Captains Creek, 40% towards Fairhaven and 10% towards town.
• 25 February: Hot Day.  Very large flyout from the camp for about 10 minutes.  About 50% headed to Captains Creek, 40% towards Fairhaven and 10% towards town.
• 26 February: Cool Day.  No noticeable flyout.  8 bats seen.
• 27 February: Cool Day.  Visited bottom of camp and a fair number of bats seen, but less than 23 February.  No noticeable flyout, but a few bats seen.
• 28 February: Mild Day.  Modest (~500?) flyout mainly towards Fairhaven.
• 1 March: Wet, cool day.  Frances checked bottom edge of camp and a few bats present.  In evening there seemed to be a few 'scouts' sent out in several directions. They returned after about 10 minutes, but no noticeable flyout by dark.
• 2 March: cool day.  The apparent lack of flyout may have been solved.  Tonight Frances looked down at the water of the Inlet and there was a large stream of bats heading across low down  towards Lakeview.  They were harder to see and we had been looking above the horizon.
• 3 March: this evening we paid a bit more attention!  The stream across the Inlet was well established by 2003 hrs.  As best as I could guess there might have been about 10 bats per second (ie 600 per minute) crossing an arbitrary line in the sky.  That went on for about 5 minutes, so perhaps 3,000 bats in that time.  Allowing for some to have left  before we started looking, and the much lower rate for the next 10 minutes before dark I'd say there are at least 5,000 bats in the camp at present.
• 4 March: we were nearly fooled tonight!  Looked down at the Inlet and no bats visible.  Que?  I then looked up at patch of unclouded sky and there they all were!  see for photos.
• 5 March:  Hot Day.  It seemed a rather dark evening compared to the 4th.  Flight started just before 2000hrs and was very strong for about 10 minutes.  Mainly low, heading across the Inlet towards Lakeview.  At one point a modest number seemed to be swirling high, perhaps going to town.  Perhaps a few more than 4 March.
• 7 March see special post re full moon fly out.
• 10 March: Powerful Owl seen at pumping station with Flying fox as prey.  Mild day with very clear sky at 1945 hours.  Big initial flight towards Fairhaven and then about 1955 a large group flew straight over our house and a bunch more went off towards Shady Gully/Betka.
• We were away for the next few days and first checked again on 20 March.  A bipolar with flight with a lot going low towards Lakeview and other high towards Fairhaven
• On 21 March there was a lot heading across the Lake and a large cloud heading towards (I think) Captains Creek (or possibly Dead Finish).  A few seeming to turn back towards the town Centre.
• On 23 March the flight across Bottom Lake seemed to be reduced but I couldn't spot any others: perhaps going up one of the valleys out of sight and over to Betka?  On 24th Frances walked past Mullet Creek around 1530 and reported that they seemed very agitated.  The flight out started at 1925 and lasted until 1940.  There seemed to be a lot heading across the Lake (with a few returning towards the end) with some landing in the Angophoras next to our place.
• A DEECA researcher visited the camp on that date and estimated the camp was "roughly double the size of his previous visit.  H estimated there to be 10-12,000 bats.  He provided a plot of the extent of the camp.
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• On 6 April the flyout was huge My estimate is at least 20,000.
• On 7 April a neighbour commented that a flock of bats was visiting the Angophoras next to our house at 0530 every morning.  It was raining on 8 April at that time but several small groups of bats left the trees before dawn.  
• On 10 April there were many bats overflying the Angophoras between 0530 and 0600.  It is on a straight line between Howe Flat and the camp  at Mullet Creek.
• The fly in on 12 April was clear, as there was much less cloud. 
• There have been good numbers flying out in the evenings (around 1800hrs) up to 22 April.  They seemed to be heading towards Fairhaven rather than Lakeview, but on the morning of 23 April good number were overflying our house around 0600hrs, seemingly coming from the direction of Lakeview or Howe Flat.
• After a few days away went and checked the camp on 2 May.  Good number of bats still.  String flyout towards Fairhaven in that evening.

Rainfall

I note the wetness of 1 March.  It had been quite cloudy on 28 February and about 2100 hrs on that day I noticed that the Bairnsdale radar was showing a rain cell near Combienbar that appeared to be heading towards Mallacoota. That arrived here very early on 1 March and rain fell reasonably steadily (max. rate 37.6mm/hr around 0200 hrs) until 0900 hrs.  As is often the case with a cell the rainfall varied a lot across the area.  There are 5 sites visible to me at the locations in this image.

Here are the falls for 1 March (ending 23:59 on that date).