Goshawk vs Collared Sparrowhawk (middle toe length)

To: "Peter Shute" <>, "'Birding-Aus'" <>
Subject: Goshawk vs Collared Sparrowhawk (middle toe length)
From: "Robert Inglis" <>
Date: Fri, 9 Dec 2011 14:27:58 +1000
My point in starting this thread was to encourage people to avoid trying to use the absolute length of the middle toe of these two species or the relative lengths of the middle toes of the two species as an identification point to determine which species is being observed. The absolute lengths and the relative lengths are irrelevant irrespective of whether the same method or not was used to obtain the measurements used to compile the tables in HANZAB.
Both species have elongated middle toes.
There is considerable overlap in the lengths of the middle toes of the two species. It is very difficult to determine the length of the middle toe when it is wrapped around a tree branch. Even high quality digital images don’t make that any easier.

Instead of comparing the middle toe lengths of the two species for identification the toes should be used in the following manner: - Estimate what percentage of the length of the middle toe is the length of the outer toe; - Note where the distal joint of the middle toe falls in relation to the base of the claw of the outer toe.

The following percentages are taken from HANZAB:
For Brown Goshawk: outer toe c. 70% of length of middle toe;
For Collared Sparrowhawk: outer toe c. 63 – 67% of length of middle toe.

OK. When you have worked out how to accurately measure that in the field let me know.

Also from HANZAB:
For Collared Sparrowhawk: distal joint of middle toe lies beyond base of outer claw. (That is probably what makes the middle toe of that species look particularly long but it could just mean that the outer toe is relatively short compared to the middle toe.) For Brown Goshawk: distal joint of middle toe is level with or shorter than base of outer claw. (Perhaps the outer toe on this species is relatively short.)

Once again, that could be hard to judge other than with the bird in the hand, however, it is possible to see this in high quality digital images of birds flying directly overhead.

Personally I would forget about using toe lengths as identification points but would rather concentrate on the appearance of the bird/s. I am sure it would be possible to eventually become proficient in evaluating the appearance of the legs/feet (thick or thin, stout or slim) if one was to observe enough examples of each species. Or if one was to take enough photos of the two species of the quality of Chris Ross’s two superb images.

Bob Inglis
Sandstone Point

No Wi-Fi used in sending this email.

-----Original Message----- From: Peter Shute
Sent: Friday, December 09, 2011 11:42 AM
To: 'Robert Inglis' ; 'Birding-Aus'
Subject: RE: [Birding-Aus] Goshawk vs Collared Sparrowhawk (middle toe length)

I thought the important thing was the relative length of the middle and outer toes. I think someone mentioned "length" in this thread without using the word "relative", but I assumed that's what they meant. Is absolute length important?

Peter Shute

-----Original Message-----
 On Behalf Of
Robert Inglis
Sent: Friday, 9 December 2011 11:47 AM
To: Birding-Aus
Subject: [Birding-Aus] Goshawk vs Collared Sparrowhawk
(middle toe length)

Question: Which has the longer middle toe - Brown Goshawk or
Collared Sparrowhawk?

edited here =


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