I tend to agree with Nikolas that it is an Arctic, although I haven't any
experience judging the amount of white wing flash in the folded wing of
standing jaegers.
I definitely agreewith Mike that it is not an adult. Although the resolution is
not great, it appears that the wing coverts and flight feathers are very worn.
Conversely, the mantle feathers are a mix of worn and new feathers. The new
feathers are darker with narrow white fringes. These are not retained juvenile
feathers they are new feathers. They are not adult feathers because the white
fringes are an immature trait that occur in juvenile, 1st and supposedly some
2nd yr birds. Looks like some of the median coverts and the remainder of the
mantle are newer than the primaries but older than the freshest mantle
feathers. My interpretation is that the primaries, secondaries, greater coverts
and tail are retained and worn juvenile feathers, the worn head and body
feathers and median coverts are 1st winter/summer, and the new mantle feathers
are 2nd winter. The bird must have hatched in mid 2009, as Mike determined.
Mike, I hadn't notice the statement in Malling Olsen & Larsson that white tips
to juvenile primaries are diagnostic of Arctic. It's a little hard to make out,
but the last photo in that book is a juv Long-tailed with white tips to the
primaries. In the Windang bird I think the retained primaries are too worn and
bleached to have retained any original white-tips. If there is a faint
impression of pale tips it may be due to fraying and bleaching of the tips.
David James,
Sydney
==============================
________________________________
From: Mike Carter <>
To: Nikolas Haass <>; Peter Madvig <>; M &
P Potter <>;
Cc: Martin Cocker <>
Sent: Sunday, 27 November 2011 11:08 PM
Subject: Help with Bird ID please
I agree with Nikolas that this is a pale morph Jaeger in very worn plumage,
definitely not a Pomarine Jaeger, most probably an Arctic Jaeger rather than a
Long-tailed (because of the pale blaze - but there is only a small amount of
white at the base of the primaries which leaves me a little unsure). However, I
have more of a problem accepting that it is an adult as the white spots on the
mantle look to be remnants of juvenile barring the presence of which I can't
explain in an adult. Perhaps Nikolas or others can. Therefore I would be
happier considering this to be an 18 month old bird in second winter plumage,
two or three years short of a full adult. But another perhaps age related
feature is the white tips to the primaries. When in juveniles these white tips
form a series of chevrons they are said to be diagnostic of Arctic Jaeger
(Olsen & Larsson 1997).
Jaegers are notoriously difficult to ID and photographs of open wings
particularly underwings are very helpful in this process.
Mike Carter
30 Canadian Bay Road
Mount Eliza VIC 3930
Tel (03) 9787 7136
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