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Old Thursday 17th August 2017, 07:09   #1
ChrisKten
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Sparrowhawk Eye size and Nape patterns.

said that I'd look through my Sparrowhawk pics for any evidence of differing Nape patterns on males and female, especially juves. Also to see if there's a relationship between eye/head size and gender.

I've over 10,000 pics of Sparrowhawks, and the vast majority are of behaviour, as that's what I'm most interested in. Finding pics that show what I'm looking for won't be easy, and I don't have the time ATM. But, I thought that I'd upload 20+ pics that are of birds that I'm positive(ish) of the gender, and see if any here that are interested can see any of the aforementioned relationships. I must admit that my eyes aren't really good enough to see these differences unless there's a stark contrast, so I can see no difference in eye size. I can see differences in nape patterns, but I'll need to sort out more pics to illustrate this.

Anyway, here's a few pics to be getting on with; I only expect 2 or 3 in this forum to have any interest in this, and they need to see the thread and have the time first

Not that it matters in this case, but all pics through double glazing

Only the first pic in this group is a female
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Last edited by ChrisKten : Thursday 17th August 2017 at 07:18.
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Old Thursday 17th August 2017, 07:12   #2
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Another 5:
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Old Thursday 17th August 2017, 07:13   #3
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More...
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Old Thursday 17th August 2017, 07:17   #4
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Last lot for now
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Old Thursday 17th August 2017, 07:52   #5
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Thanks for starting this Chris.

We need a 'Jane' to dissect the pictures because my eyes are a bit like yours and she is great at this sort of thing. The point made in the other thread was that the eye size doesn't change between sexes but with males being a 1/3 smaller proportionately their eyes will be larger compared to their head size eg 1cm vs 10cm 1in10 compared to 1cm vs 7cm 1in7 (obviously not the correct measurements) - or put simply the males eyes will appear larger.

Lets see where this takes us anyway and lets hope that we can get a good selection of birds for comparison.

Should add I don't have any close ups of SH to help...
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Old Friday 18th August 2017, 05:41   #6
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This seemed like a good idea at the time, but with only the two of us interested, and neither having great eyesight, perhaps not such a good idea after all.

I'll check back on the thread at the weekend or next week maybe... I won't sort out any more pics though.
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Old Sunday 20th August 2017, 16:49   #7
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Quote:
Originally Posted by ChrisKten View Post
This seemed like a good idea at the time, but with only the two of us interested, .......
Chris, There's at least three interested! But I'm like everyone (?) else: I'm waiting for someone else to do the legwork and tell us the answer. I was tempted to make a start but then I thought what could be involved - e.g. download images and put male/female side by side in a 'compare' tool, scale one or the other up or down, then compare across directly. I tried the 'quick & dirty' way, just eye-balling (not supposed to be a joke...) images one after the other, and very soon got too confused. Mind you that happens quite easily.

Just to confuse things further, I've a pet notion that the eye in Sparrowhawk and Goshawk is a similar size, but the head is larger in Goshawk, making the eye look relatively smaller. Might be nonsense, probably is, but all my Goshawk images are of birds a million miles away so I'll never be testing it.

Whatever, it's always a great pleasure to look at your Sparrowhawk images!

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Old Wednesday 23rd August 2017, 07:05   #8
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I think we're going to have a long wait for any responses, Brian

(I will have a proper look through my images when I feel up to it - I've an appointment with the Opticians in a few weeks, maybe new glasses will help )
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Old Thursday 31st August 2017, 15:21   #9
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I've heard the same thing (re eye size) said about peregrines but you'd really need to examine birds of both sexes in the hand to confirm it. By the way - those are beautiful shots, ChrisKten.
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Old Tuesday 12th September 2017, 09:13   #10
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Looks dangerous yet beautiful! Nice find
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Old Yesterday, 14:03   #11
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Hello Chris... I know this is going off topic but do you mind if I ask you a pigeon question??
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Old Yesterday, 18:29   #12
ChrisKten
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Originally Posted by Cinereous View Post
Hello Chris... I know this is going off topic but do you mind if I ask you a pigeon question??
Of course I don't mind... ask away (Although I can't promise to know the answer )
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