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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