birding-aus

White-throated Needletails Are still in Eastern Australia

To: Birding-Aus <>
Subject: White-throated Needletails Are still in Eastern Australia
From: Michael Tarburton <>
Date: Mon, 15 Mar 2021 09:37:18 +1100
Morning Birdos

While it will only be 2-3 weeks before most of the WTNT depart from the Eastern 
coast of Australia they are still visible.  You may need to use your binoculars 
because they tend to spend more time out of normal vision range just prior to 
their departure.  On Friday I watched quite a few flocks feeding between 80 and 
600m but yesterday even though they were right overhead, I could only see them 
without my bins for about a minute.  They ranged from 800m to 1,400m above me.  
Food does reach these heights particularly above ridges where the wind is 
bounced upwards taking the flying insects skyward and at the same time enabling 
the swifts to fly without beating their wings.  I recall that in my last year 
at Massey University we were provided with data from the NZ & Aus  BOM 
departments that traced the air Australian butterflies were in when they 
arrived in NZ.  I think they did this on three occasions and each time the air 
carrying the insect was traced at quite some height to Central Gippsland in Vic.

A Japanese paper to be released soon in Pacific Science shows that 3 WTNT with 
geo-locators on them that came to Australia last year did what I had predicted 
some years ago when departing for the Northern Hemisphere.  Two of the birds 
were in Qld when they recived the call to return to Hokkaido, so they headed 
off too high to be seen from the ground, through the NT, one leaving our shores 
near Darwin, the other from the Kimberley.   The third bird had just reached 
Tassie when it recieved the call to return home, so it went high back to 
Melbourne then west through Vic, S.A. and W.A. departing our island near Port 
Headland.  The fact that sightings of WTNT in central SA, N.T, and W.A. are 
extremely rare demonstrate that they are flying too high to be seen from the 
ground.  

SO Now, before they get too high is a good time to look out for them and watch 
their high speed flight, their complicated pair-bonding display flights.  
Please count how many in the flock and report it some place that I can find it 
so I can continue to monitor their decline.

So if you live down the east coast of Australia, enjoy one of our greatest 
birds before they depart.

Cheers

Mike Tarburton.
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