RE:Raptor ID tail shape

To: <>
Subject: RE:Raptor ID tail shape
From: "Jeff Davies" <>
Date: Fri, 12 Aug 2005 19:21:58 +1000
Hi Chris,
I confess my comment on tail shape was a bit casual, so I'll elaborate. Generally speaking I would be surprised if tail-feather tip shape differs substantially if at all between Sp.hawk and Gos. and is not the reason for a square tail in Sparrowhawk. I agree with you that square/round tail tip is a result of the relative lengths of outer verses inner rectrices. The individual in question has a roughly parallel sided foulded tail eg. the feather shafts are parallel. With both Gos. and Sp.hawk the individual tail feathers from 1 to 6 are approx. the same width, what does change from 1 through to 6 is the tip profile shape. After being parallel sided for most of its length with a central shaft( both veins of equal width ),T1 eventually tapers to a rounded tip the sides therefore curve for the last 1/4 of it's length. The shaft of T6 on the other does not run centrally which results in the outer vein being substantially narrower than the inner and therefore the outside edge looking straight for the entire length. This is what makes a tail look angular when all the tail feathers are roughly the same length. A same tail-feather length tail would not look as square if all of the feathers T1 to T6 where the same shape as T1. You don't see an angled corner in Gos. because T6 inwards get longer incrementally but if you left it's T6 intact and trimmed its other tail feathers to the same length it would appear just as angular as a Sp.hawk.
There have been a number of Sparrowhawks around Heidelberg in recent years and when I have seen them straight tailed like the bird photographed this is when the notch can be most apparrent. After saying Sparrowhawk has tail-feathers of equal length I am now going to contradict myself slightly by saying that is not quite the case. T1 often appears a fraction shorter, maybe this is where the apparrent notch comes from.
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