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Looking out my front window in suburban Wangaratta this morning I noticed a white butterfly fluttering by, and a few in the background, and I thought gee, the Cabbage White butterflies are bad this year!.  But then another pair flew by and another, all in the same south-westerly direction.

Something stirred in the back of my brain about butterfly migrations so I went out into my back yard to have a look.  Sure enough there was a steady stream of butterflies coming from the northeast, but when one passed close by I could see the wings were edged with black, not like Cabbage Whites at all.  I'm not very practiced at identifying butterflies, especially fluttering by, and wished for a butterfly net to capture one to get a good look at it. 

Pulling out my Common & Waterhouse I was a bit overwhelmed by the number of white butterflies (not entirely white, but classified as whites).  I couldn't see any colour on the butterflies fluttering by, but eventually looking at the distribution maps settled on the Caper White, which has minimal colour and a mainland-wide distribution and to the north.  Common & Waterhouse notes that:

"Immense migratory flights of this species frequently occur in southern Queensland and New South Wales and sometimes extend into Victoria.  Entomologists at the Australian Museum are collecting information about such flights, but it is still too early to reach conclusions about their function in the biology of the species.  The larval food plants do not normally grow farther south than about the latitude of Newcastle in the east and Griffith in the south-west, but migratory flights often extend well into Victoria and sometimes to southern Victoria"

Weird that the migrations are away from food plants.  Why??

I put a chair up against one fence and counted butterflies passing the wall of next-door's garage while timing 2 minutes on my phone.  I counted 22 butterflies passing, mostly within a few metres of the ground, but some up to maybe 30 metres.  Then I paced out the distance: 23m.  That's 29 butterflies per metre per hour.  This was at midday, but I had been watching the butterflies passing for about an hour.  Guessing that the migration was 20km across, that's half a million butterflies in an hour.  What?  I had to recalculate.  Yep.  And the migration didn't stop till mid-afternoon.  It's a lot of butterflies.  It was a fine day, 19°C, partly cloudy, 80% humidity, and still, so it definitely wasn't that the butterflies were wind-blown.  And there were none flying northeast.

Eventually I noticed that some were stopping to feed on my sage bush, which was in full flower.  They must have been hungry, because they let me get close enough to photograph them with my phone.  Not the best photos, but enough to confirm the identification as Caper White, Belenois java.  Interestingly the photo on the Australian Museum website seems to also be on sage bush.

Geoff Park recorded a migration on 19 November 2015 in his excellent Natural Newstead blog, and Angair Factsheet 9 describes a migration on 29 November 2004Here is a video of Caper White butterflies in Brisbane in November 2016.  I only found one reference to a Caper White migration in October at Strathbogie Ranges Nature View.

Snap Send Solve is a smartphone app, available on Google Play and the App Store that makes it very easy to report a whole range of issues relevant to open space users in Australia and New Zealand.  It claims to report to 'every Council in Australia and New Zealand and a growing list of alternative asset managers". 

Whilst it is very easy to make a report, you have to be aware that unless a management agency pays to receive full reports, they only get a summary.  The summary leaves out the photos you took for the report, it leaves out any text description, and your contact details.  In my area I have made the mistake of assuming Yarra Valley Water have received my water leakage reports adjacent to Merri Creek, and wondering why they hadn't got back to me.  Well, I found out they don't subscribe to Snap Send Solve, and so had no way to contact me. 

And I should have known this if I had properly read the email confirmation that Snap Send Solve, which says

"...Your report has been sent to Yarra Valley Water. ... Reports sent to Yarra Valley Water only include the Incident Type, Address and Geocode". 

Discussing this with a Yarra Valley Water staffer, they asked that I call up the fault reporting line to make sure the reports got into the system.  I did this and found that only 3 of the 4 reports were in the system, that one had been investigated but they didn't look in the right place, as the drain wasn't in the property Snap Send Solve identified but in the open space below the property.  The other two had been investigated, but they hadn't yet been able to find the source of the leak.

So if you use Snap Send Solve, read the email they send you, and not just the first sentence or two!

The Waterways and Open Space Management Blog is brought to you by Tony Faithfull.  Views expressed in articles are his views and are not necessarily endorsed by anyone else.  It is unapologetically subjective.

Tony has spent 30 years working on various aspects of waterway management, for the Wildlife Reserves at LaTrobe Uni, at Yarra Bend Park, for Merri Creek Management Committee, and as a consultant.

The purpose of this blog is to identify issues in open space management, assess agencies' responsiveness in managing these issues once they are reported, and to get discussion going.

The focus of the blog is on areas Tony visits, and mostly that is in the Merri Creek vicinity.

 

I have long wanted to get a handle on the value of Merri Creek, as a way of arguing for more investment in the Creek and its parklands.  There are many aspects to its value of course, value for habitat, value for users, value for neighbours...

One way to measure value is through property value.  I believe there is a premium on real-estate near Merri Creek, and want to get an idea of what that premium is.  And how far from Merri Creek is the value felt?  I have often been boggled by for-sale signs that boast "Near to Merri Creek", even if the property isn't what I would call near.  But what would I know? Real Estate agents must have a pretty good idea how close to Merri Creek a property has to be to make it worth putting this on a sign.