Don't we have to wait for BARC acceptance ? That makes it a 2007/8 tick,
not this year.
Ho.
Tony,
-----Original Message-----
From:
On Behalf Of Graham
Etherington
Sent: Wednesday, August 02, 2006 12:51 PM
To: scouler
Cc: birding
Subject: GHL - Reverse Migration or overshoot?
Colin and all,
The GHL was found in 19 Jun. If the bird hadn't been in the country too
long before that, then it's occurrence will have coincided with it's
northerly spring migration, so this would be a reverse migration. If it
had been round for 9 months, then as you rightly point out it would be
an overshoot. The problem that I see with both these scenarios is not
the distance travelled (there are plenty of vagrancy records which beat
the GHL
distance) but the direction travelled.
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'. (There's a great piece on vagrancy shadows in Rare
Birds in Britain and Ireland: A Photographic Record by David Cottridge,
Keith Vinicombe).
An interesting record, whatever, and it's on my list!
Cheers,
Graham
On 8/1/06, scouler <> wrote:
>
> Hello birders,
>
> Shane Brady's reference to hearsay from a local at Burren Junction to
> the effect that the GHL has been in the area for the last 9 months
> seems to cast some doubt on the theory that it got there by "reverse
> migration".
>
> Hayman et al "Shorebirds indicates that the population which breeds
> in Manchuria migrates to its wintering grounds (Nepal-South China) in
> about September. So the timing of the bird's reported arrival at BJ
> would appear to coincide with that of its normal southward migration.
> Its presence at BJ might therefore be the result of an overshoot.
>
> If so, it would be a colossal one, more than double the length of the
> usual southbound journey of the species, even given the fact that GHLs
> has been known to wander from their normal flight path and turn up as
> vagrants in the Andaman Islands, Malaysia, the Philippines and
> Indonesia.
>
> Colin Scouler.
>
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--
Graham Etherington
Indooroopilly,
Queensland, Australia
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