Gooday Peter
The term "square tail" refers to the overall shape of the tail in the Collared
Sparrowhawk. When you look at the tail of a CSH there is a definite corner
where the side of the tail meets the base of the tail. It is angular at this
juncture. In other words it is not a smooth progression from the side to the
base as in the BG but does a dog-leg or goes across at a right angle, or as you
say, there is a "sharpness" to the corners. It can be said to be true of both.
The base of the CSH tail is almost straight across, although it can appear that
there is a slight bulge or roundness when the CSH tail is fanned. But this
bulge is minimal and nowhere near as prominent as in that of the BG. Some of
the latter pictures show this comparison well. I find that if one gets a good
enough view of a CSH tail that this straightness is always evident.
As far as the longer head and neck, I haven't heard that before. It may simply
be that you have delved into the texts a little deeper than myself.
When I blew up photo 4 I was able to make out the extended middle toe of the
CSH (top bird). You should see it quite well. Whereas in the BG (bottom bird)
in the second photo you can see that this middle toe is nowhere near as long.
I agree with Anthony M when he says that the birds are both the same sex, but I
couldn't say what sex that might be. The size difference between them seems to
be consistent with this. Without something else in the photograph to refer to,
however, I find it a little hard to say.
Regards,
Michael Wood
I think I agree with this (CSH and BG), but I'm not sure about the top bird in
the first photo.
I must admit I've been confused by the term "square tail". Does this refer to
the "sharpness" of the corners, or the straightness of the end? Looking at the
sihouettes of both species in figures 8.3 and 8.4 of Stephen Debus's "Birds of
Prey of Australia", I'm thinking it's both but mainly the latter.
In all his drawings of spread Collared Sparrowhawk tails, the tips are in a
dead straight line - there's no bulging out of the inner feathers at all. He
descibes it as "square or notched". The inner tail feathers of the upper bird
in the fist photo do very definitely bulge outwards, but not as much as in his
drawings of spread Brown Goshawk tails. The lower bird's ragged tail has a
very definite bulge. I don't know how much regrowing feathers can affect this
bulge. What order do they moult in?
He says the Brown Goshawk has a longer head and neck, and the upper bird in the
first photo does appear to have a shorter head/neck than the lower.
He also says that the CSH wing has a more rounded trailing edge, and this also
appears to be true in the first photo.
There are also those who say you simply can't tell without a close look at the
middle toe.
Peter Shute
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