Black-winged Petrel, White Tern, False Killer and more: SOSSA pelagic of

To: "'Nikolas Haass'" <>, "'Chris Corben'" <>, <>, "'Paul Walbridge'" <>, "'Alan Gillanders'" <>, "'Raja Stephenson'" <>
Subject: Black-winged Petrel, White Tern, False Killer and more: SOSSA pelagic off Wollongong NSW
From: "Jeff Davies" <>
Date: Mon, 30 Jan 2012 21:48:33 +1100
Actually Nikolas I do have a comment on the Jaeger photos, they are
fantastic and thanks Raja for putting them out there for us to look at.
There are surprisingly fewer shots of Arctic off Australia in basic plumage
on the internet compared to the other two species, I guess it's because they
are more of an inshore species while pelagic trips are focused on the
continental shelf drop off zone.


Thanks Nikolas and Raja, cheers Jeff.





From: Nikolas Haass  
Sent: Monday, 30 January 2012 8:34 PM
To: Chris Corben; ; Paul Walbridge; Jeff
Davies; Alan Gillanders; Raja Stephenson
Cc: Debi Shearwater; debi shearwater; Jennifer Green
Subject: Black-winged Petrel, White Tern, False Killer and
more: SOSSA pelagic off Wollongong NSW


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 mine and the ID should be Short-tailed Shearwater. 


Here are Raja's pictures of a Sooty Shearwater (I hope ;-)

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...)







---------------- 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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