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متابعة الطيور في توتي Ringing on Tuti

الكاتب: موسوعة النيل Nilopedia الرقم المرجعي: AA-00422 مشاهدات: 898 أنشيء: 2016-02-19 11:26 آخر تحديث: 2016-03-01 11:16 0 التقدير/ الأصوات

Friday, 31 May 2013

For a while now I have been wanting to start a project to study Cinnamon Weavers. A few months ago I received some rings (bands) and I hope to start in earnest when the Cinnamon weavers are back in breeding plumage at my one known nest site at Wad Medani (they were not in breeding plumage when I visited with Terry on May 11th). Part of my study involves determining how to identify females and males when they are in non-breeding plumage, so for this reason I need to compare them with close relatives. Last weekend I went out to Tuti to try and net some birds at one of the Northern Masked Weaver colonies. I had some success in catching 7 birds (4 males and 3 females), plus a few other species, including Little Bee-eater, Plain Martin, Common Bulbul and House Sparrow.


 Little Bee-eater, Tuti Island 25th May 2013

Little Bee-eater, Tuti Island 25th May 2013

Plain Martin, Tuti Island 25th May 2013

Common Bulbul, Tuti Island 25th May 2013

House Sparrow, Tuti Island 25th May 2013

I was able to get plenty of measurements of the weavers; concentrating on things like bill structure, as I have the impression that Cinnamon Weavers may have slightly larger bills than Northern Masked Weavers. Female Northern Masked Weavers are supposed to have a dark eye, but I have seen several individuals with pale eyes, including one of the birds caught at Tuti (see below). However, I have the impression that Cinnamon Weavers may have pale eyes more frequently, though this will need further investigation. I also wish to determine whether age affects eye colour as in many other species.

Male Northern Masked Weaver showing its leg ring that can be read in the field,
 Tuti Island 25th May 2013

 Male Northern Masked Weaver, Tuti Island 25th May 2013

 Female Northern Masked Weaver with a pale eye, Tuti Island 25th May 2013

Female northern Masked Weaver with a dark eye, Tuti Island 25th May 2013

I have also been recording various feather and wing measurements, such as the wing formulae, which compares the lengths of each primary feather with the longest feathers. One good criterion for identification of birds in the hand is the structure of the primary feathers, such as which are emarginated (have a narrowing on the outer web) and which are notched (have a narrowing on the inner web). Unfortunately, this does not appear to be a useful feature for separating Northern Masked and Cinnamon Weavers, as all of the Northern Masked Weavers were emarginated on the 3rd, 4th, 5th and 6th primaries (using the British numbering system that counts the short outermost primary as number 1) and I have a photo of a Cinnamon Weaver stretching its wing that shows exactly the same pattern of emargination.

Northern Masked Weaver wing, Tuti Island 25th May 2013

 Cinnamon Weaver wing, Wad Medani October 2012
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