birding-aus

GHL - Reverse Migration or overshoot?

To: "Mike Carter" <>
Subject: GHL - Reverse Migration or overshoot?
From: "Graham Etherington" <>
Date: Wed, 2 Aug 2006 18:50:59 +1000
Mike Carter wrote:
"What you have written is very much a generalisation.............But
what if it normally migrated north up the Asian coast to reach North
Korea then turned
left to head west inland. In my view a very likely scenario. A mirror image
of that with some extra mileage could take it to Burren Junction!! Support
for my reverse migration theory!!"


Crikey Mike! And you accuse me of making generalisations!!!
Anyway, like I said, I've not had chance to study the distribution
maps of GHL - my books are all sat in a container, waiting for customs
in the Port of Brisbane :-(
What I can figure out though is that if GHL winters no further east
than Hong Kong then it will have to breed as far west as Lake Baikal
to be a straight over-shoot or reverse-migrant, and that would only
get it to the west coast of Australia. It would have to breed in
Kazakhstan to make it to Burren Junction! I don't know if it does
breed that far west (Lake Baikal that is, not Kazakhstan) and I also
don't know if GHL is a common wintering bird in HK. If you could set
me straight on this I'd appreciate it.

What I'm actually saying is that the reverse migration or overshoot
theory might not be the only explanation of how the bird arrived here.
And I'm definitely not trying to cast any doubts over the origin of
the bird either. Nobody knows how long this bird has been wandering
the earth, lost. It could have migrated along a number of routes
before it made it to Australia.

Interesting discussion anyway.
Cheers,
Graham




On 8/2/06, Mike Carter <> wrote:

 "Graham Etherington"  wrote in reponse to Colin Scouler

> Going from the distribution of GHL, it appears to do a NE - SW
> migration in autumn and visa-versa in spring. So, regardless of
> whether it was on its wintering grounds (Nepal-South China) and
> undertook a reverse migration (SW instead of NE), or it was an autumn
> overshoot (again, it should have been going SW) and it flew the
> distance from the wintering grounds to that of Burren Junction, then I
> figure it should have turned up in Madagascar!
> I'd have to study the distribution maps a bit more carefully, but I
> don't see how Australia would end up as part of an over-shoot
> 'shadow'.

What you have written is very much a generalisation. What we are concerned
with here is the movement of one individual. Those individuals which winter
in Hong Kong or further east must migrate virtually north/south. It is even
possible that some could have a slight westerly/easterly component in their
direction. Either way an overshoot or reverse migration could bring the bird
to Australia, albeit more likely the Kimberley than NSW. But what if it
normally migrated north up the Asian coast to reach North Korea then turned
left to head west inland. In my view a very likely scenario. A mirror image
of that with some extra mileage could take it to Burren Junction!! Support
for my reverse migration theory!!

Incidentally, one of my Japanese books has a photograph of a Grey-headed
lapwing standing in rough grassland that looks as though it could have been
taken at Burren Junction. And I ticked it too - and before I voted that BARC
should accept it!!

Mike Carter
30 Canadian Bay Road
Mt Eliza    VIC     3930
Ph:  (03) 9787 7136
Email: 




--
Graham Etherington
Indooroopilly,
Queensland, Australia
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