Antarctic terns, Kangaroo Island: addendum

To: "'Birding-Aus'" <>
Subject: Antarctic terns, Kangaroo Island: addendum
From: "Simon Mustoe" <>
Date: Sun, 10 Sep 2006 18:53:39 +1000
After chatting with Mike Carter, I regret not caveating my description of
the birds - I wrote the piece last night on a palmtop and it was rather
The descriptions I gave were as I saw the birds at a distance of about 300m.
The photos I have seen I believe are slightly misleading but only as much as
descriptions of the birds at distance. For instance, I saw grey up to the
throat...perhaps this might have been shadow. The photos show little grey at
all but I think they are over-exposed as you would expect images of largely
white birds to be in strong sunlight against dark backgrounds such as rocks.
There are also horrendous JPG compression artifacts that make the wings look
comparatively short compared to the tail and place dark edges on the inside
edge of various features, including tail feathers (on one photo this is
evident on the outer web of the right tail feather and the inner web of the
left tail feather - it is probably shadowing with some JPG artifacts). 
Albeit difficult to specify detail, the distant views of the birds gave a
good impression of overall patterning and the white cheeks were highly
distinctive compared to the grey underside and black cap - the photos don't
show this for reasons I explain above. I also describe the secondaries as
having broad white tips - sorry, they are scapulars. The extent of white I
observed may have been exaggerated by the strong sunlight at distance.
I have also been questioned about my description of the bill of Antarctic
Tern compared to Arctic. I don't really have a view on this except insofar
as compared to the 1000s of summer plumaged Arctic Terns I have seen, the
bills appear more dagger-shaped, broader at the base and brighter. I think
it is very important however, to be honest to what one sees at the time
rather than led by either enhanced digital images or field guides. Read into
my description what you will but the combination of characteristics clearly
suggest Antarctic Tern. Anything else is just what I observed, albeit
without the benefit of either (a) very close range; or (b) images to
scrutinise and amend my description once I got home. 
Mike asked me to mention how many birds I saw. Owing to the difficult
viewing conditions I was sadly unable to do a head count and I only
concentrated on red-billed individuals since these were easiest to detect at
distance. A minimum of three birds were present but perhaps many more, since
all the terns regularly took off and resettled elsewhere, it was hard to
Thanks Mike for your constructive suggestions. 
Kind regards,
Simon Mustoe. 

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