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Re: Pied Oystercatchers on Lord Howe and Norfolk Islands

To:
Subject: Re: Pied Oystercatchers on Lord Howe and Norfolk Islands
From: (David Torr)
Date: Thu, 2 Apr 1998 13:44:05 +1000
     Prevailing winds I would have thought make it easier for an "Aussie" 
     to accidentally go east than for a "Kiwi" to go west???


______________________________ Reply Separator _________________________________
Subject: Pied Oystercatchers on Lord Howe and Norfolk Islands
Author:   (Dr Richard Nowotny) at ~pau-smtp
Date:    02/4/98 11:35


Mike Carter, birder of note, twitcher, seabirder and sometime desert 
dueller, has posed an interesting question:   Are the pied oystercatchers 
seen occasionally on Lord Howe and Norfolk Islands Pied Oystercatchers 
(Haematopus longirostris), South Island Pied Oystercatchers (H. finschi) or 
both?
I have more than a passing interest having seen a pied oystercatcher on a 
visit to Lord Howe Is in Nov 96.  Unfortunately I was sufficiently dozey at 
the time not to have treated the sighting with anything but the mildest of 
interest.  I neither realised that such sightings are very infrequent nor 
that it might be either of these two very similar species (I therefore made 
no attempt to identify it to species, assuming it was an Australian origin 
Pied Oystercatcher).
I note that Ken Simpson in the island lists at the back of his field guide 
lists Pied Oystercatcher as a vagrant to LHI and SIPO as a vagrant to NI. 
HANZAB (assumed to be the current authority?) notes single vagrant PO's on 
LHI in 1950 and 1982, and vagrant PO's on NI in 1960 (x30), 1970 (x2) and 
1983 (single).
With regard to SIPO's HANZAB states:  "Vagrant black-and-white 
oystercatchers on Norfolk and Lord Howe Is have been attributed to this 
species but not acceptably confirmed and are considered further under Pied 
Oystercatcher (qv)."
As I understand Mike Carter's argument (and I can't purport to have heard it 
fully expounded) New Zealand's closer proximity to NI (772 kms cf 1367 kms 
from Australia) and the SIPO's known propensity for flocking and migrating 
make it the more likely vagrant to Norfolk Is and should have caused HANZAB 
to take a stronger position regarding the likelihood of the Norfolk Is birds 
being SIPO's rather than PO's.
I assume that the opposite proximity issue for LHI (570 kms from Australia 
cf 1350 kms from NZ) and perhaps the records of only single birds outweigh 
the rather limited migratory behaviour in PO's and make this the more likely 
species on LHI.
Anyone feel like making a contribution?  (I will send all contributions on 
to Mike Carter for his interest/edification - in hard copy since he is not 
"on-line".)
Richard Nowotny
     
     
From:  Dr Richard Nowotny
             Melbourne, Australia
             Tel. (w) 61-3-9214.1420
             <>
     

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