Thanks Chris, Paul & Jeff for your comments!And yes, Alan, this is the kind of
discussion that makes this forum valuable.
I agree with all three commentators and we will change the captions to these
pictures. I also agree with you, Chris, that Sooty and Short-tailed are by far
more similar to each other than both are to a Wedgy. I would be very
embarrassed if we had captioned this bird "Wedge-tailed Shearwater"! However, I
don't necessarily agree that the comparison to an "outgroup member", such as a
Wedgy or - at the other end - to a Flutterer, is totally irrelevant. I think
that the flight style (depending on the weather/wind condition) is important,
too, although it apparently doesn't always work: I am still surprised how
outstanding this bird's flight style was and how different it looked from all
the other present Short-tailed Shearwaters.
As I said, I do agree that the field marks you guys mentioned are "harder" than
mineand the ID should be Short-tailed Shearwater.
Here are Raja's pictures of a Sooty Shearwater (I hope ;-)
http://www.adarman.com/Birds/Petrels-Shearwaters/Sooty-Shearwater
Actually, I think that this particular bird is one of your example birds "Sooty
at rest", Paul. Especially picture 2 in Raja's series shows that even a Sooty
can show a steep forehead. This underlines that we always need to look at a
combination of field marks.
BTW, I also had my first encounters with Short-tailed Shearwaters in direct
comparison to Sooty Shearwaters in California, when I used to be a pelagic
leader on Debi Shearwater's trips there. Because of my failure to ID them she
kicked me out and I had to flee to Australia - just kidding...
Thanks again for the comments (I am actually surprised that no one commented on
some of the jaegers...)
Cheers,
Nikolas
----------------
Nikolas Haass
Sydney, NSW
________________________________
From: Chris Corben <>
To: "" <>
Sent: Monday, January 30, 2012 3:11 PM
Subject: Black-winged Petrel, White Tern, False Killer and more: SOSSA pelagic
off Wollongong NSW
Hi all
I think Short-tailed vs Sooty is a very interesting problem in many ways. In
the hand they are always easy to tell, even ignoring measurements, just by the
colour of the underwing. However, seeing that in a reliable way in the field is
extremely difficult and hugely lighting dependent, so it's very easy to be
mislead, even if you know exactly what to look for.
This is where digital cameras have made a huge difference. Even though a photo
lacks a whole lot of important cues, it still represents a very unbiased view
of something. The photons really did this, without any filtering by millions of
neurons in the brain which are there for the very purpose of letting us see
things which aren't there! This filtering is why we are so clever about what we
see, but it still means that we largely see our lives through a succession of
optical illusions!
Irrespective of all the ways in which Sooty and Short-tailed can appear to
differ, they are still FAR more like each other than either is like anything
else! While I can appreciate Nikolas' point about confusing the bird with a
Wedgy, the fact is that ANY Sooty is always going to look far more like a
Short-tailed than a Wedgy, once you see it well. I am sure you could briefly
think a Fluttering looked like a Wedgy, but doing so would not be support for
it being a Huttons, even though you could argue that a Huttons looks MORE like
a Wedgy than a Fluttering looks like a Wedgy. The difference between a Sooty
and a Short-tailed is so small compared to the difference between either and a
Wedgy, that temporarily thinking it looked like a Wedgy just isn't really
relevant.
I have had excellent opportunities to watch both Sooty and Short-tailed
together on many occasions, and perhaps the best of these have been in
California, where the argument has been expressed that you cannot tell them
apart (but few would accept that). I have had plenty of examples where the
difference between a Sooty and a Short-tailed was so obvious, that I started to
wonder why I ever thought they were confusing. And then, just when feeling
extra good about it, another bird would come along which made everything look
confusing again, despite having excellent views. None of this is surprising,
because it's just an inevitable consequence of the bell curve, which is so
basic to all of biology.
The bird off Wollongong strikes me as more like a Short-tailed and Nikolas as
more like a Sooty, and the photos are good. The fact that we cannot instantly
agree on its identity when faced with photos this good is just an unambiguous
testament to the genuine difficulty of this problem!
Cheers, Chris.
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