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Bittern male or female
http://lbcarchive.co.uk/forum/viewtopic.php?f=22&t=20005
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Author:  Andy Atkinson [ Thu Nov 07, 2013 8:13 pm ]
Post subject:  Bittern male or female

Can anybody please tell me if the bittern i posted is male or female & how do you tell?

Author:  Nick Clayton [ Thu Nov 07, 2013 11:56 pm ]
Post subject:  Re: Bittern male or female

The sexes are alike Andy

Author:  John Clarkson [ Fri Nov 08, 2013 10:38 am ]
Post subject:  Re: Bittern male or female

Alike but not identical. There is a considerable size difference; males are bigger on all measurements and in terms of weight the male is on average about 400gm heavier. You'd probably need them side by side to tell though

John

Author:  Geoff Williams [ Fri Nov 08, 2013 9:35 pm ]
Post subject:  Re: Bittern male or female

John Clarkson wrote:
Alike but not identical. There is a considerable size difference; males are bigger on all measurements and in terms of weight the male is on average about 400gm heavier. You'd probably need them side by side to tell though

John

From what I've read, the lores are blue on males and grey or greyish on females even on November birds, so I would say that the bird was a male.

Author:  Nick Clayton [ Fri Nov 08, 2013 10:16 pm ]
Post subject:  Re: Bittern male or female

Geoff Williams wrote:
John Clarkson wrote:
Alike but not identical. There is a considerable size difference; males are bigger on all measurements and in terms of weight the male is on average about 400gm heavier. You'd probably need them side by side to tell though

John

From what I've read, the lores are blue on males and grey or greyish on females even on November birds, so I would say that the bird was a male.


I would be interested to know where you read this Geoff, there is no mention of this feature in BWP which I directly quoted on my original reply.

Author:  Nick Clayton [ Fri Nov 08, 2013 11:21 pm ]
Post subject:  Re: Bittern male or female

Nick Clayton wrote:
Geoff Williams wrote:
John Clarkson wrote:
Alike but not identical. There is a considerable size difference; males are bigger on all measurements and in terms of weight the male is on average about 400gm heavier. You'd probably need them side by side to tell though

John

From what I've read, the lores are blue on males and grey or greyish on females even on November birds, so I would say that the bird was a male.


I would be interested to know where you read this Geoff, there is no mention of this feature in BWP which I directly quoted on my original reply.


I have saved you the trouble Geoff see link below but this is a feature only present during the reproductive period (mid-March to June) so not applicable to Andy's photo. http://serwisy.umcs.lublin.pl/marcin.polak/publikacje/Ibis-Biometrics.pdf

Author:  Geoff Williams [ Fri Nov 08, 2013 11:57 pm ]
Post subject:  Re: Bittern male or female

Nick Clayton wrote:
Nick Clayton wrote:
Geoff Williams wrote:
John Clarkson wrote:
Alike but not identical. There is a considerable size difference; males are bigger on all measurements and in terms of weight the male is on average about 400gm heavier. You'd probably need them side by side to tell though

John

From what I've read, the lores are blue on males and grey or greyish on females even on November birds, so I would say that the bird was a male.


I would be interested to know where you read this Geoff, there is no mention of this feature in BWP which I directly quoted on my original reply.


I have saved you the trouble Geoff see link below but this is a feature only present during the reproductive period (mid-March to June) so not applicable to Andy's photo. http://serwisy.umcs.lublin.pl/marcin.polak/publikacje/Ibis-Biometrics.pdf

I was reading a piece on the RSPB Old Moor and Dearne Valley web page 'A bit about the Bittern' which showed a picture of a Bittern with blue lores dated 1/11/2011, but reading further it says the picture was actually taken in Feb 2013 so it is presumably more a breeding season thing as you say. However looking at Andy's photo I think you can see a hint of blue.

Author:  Nick Clayton [ Sat Nov 09, 2013 12:05 am ]
Post subject:  Re: Bittern male or female

Geoff Williams wrote:
Nick Clayton wrote:
Nick Clayton wrote:
Geoff Williams wrote:
John Clarkson wrote:
Alike but not identical. There is a considerable size difference; males are bigger on all measurements and in terms of weight the male is on average about 400gm heavier. You'd probably need them side by side to tell though

John

From what I've read, the lores are blue on males and grey or greyish on females even on November birds, so I would say that the bird was a male.


I would be interested to know where you read this Geoff, there is no mention of this feature in BWP which I directly quoted on my original reply.


I have saved you the trouble Geoff see link below but this is a feature only present during the reproductive period (mid-March to June) so not applicable to Andy's photo. http://serwisy.umcs.lublin.pl/marcin.polak/publikacje/Ibis-Biometrics.pdf

I was reading a piece on the RSPB Old Moor and Dearne Valley web page 'A bit about the Bittern' which showed a picture of a Bittern with blue lores dated 1/11/2011, but reading further it says the picture was actually taken in Feb 2013 so it is presumably more a breeding season thing as you say. However looking at Andy's photo I think you can see a hint of blue.


http://www.rspb.org.uk/community/placestovisit/dearnevalley/b/dearnevalley-blog/archive/2013/02/25/a-bit-about-the-bitterns.aspx

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