Hi Belinda,
A classic example of why you have to be very careful using the tail as an ID
feature for Sparrowhawk/Goshawk. I'm tempted to forward this to a few
people I've argued about this with, but that would just be petty :)
Peter, the fact is that like wings, raptor tails can be held differently
than expected. For example Black Kites can either have forked or square
tails depending on how splayed the feathers are. The first flight photo
where the tails look "pointed" the tails are held very tightly bunched,
possibly for speed. The second set, where the tail looks "squarer" is
probably because the feathers are being held less tightly bunched. Look at
the relative width of the tail in each photo. Add to that the possible
shapes you get when outer feathers are missing, or where inner feathers are
missing, or any combination of the above, and shape becomes pretty
unreliable. As seen in Belinda's photo of the pair together size is also
pretty fraught. I hate to say it, but the GISS of the bird is probably more
useful in flight. I've stood with a friend of about equal bird ID skill
watching an accipiter in flight, and we argued heatedly about which it was,
without resolving the issue (I still say it was a sparrowhawk!). Our
argument boiled down to me using the GISS, and my friend using the tail. If
I had to boil down what I call the GISS of a sparrowhawk into words, I would
say it is smaller, sleeker, more slender, faster and more acrobatic than a
goshawk. As with migratory waders (think primary projection length), tail
moult can really stuff you up on ID here.
Regards,
Chris
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