Results 1 to 4 of 4

Thread: Ageing of Bonaparte's Gull

  1. #1
    Junior Member
    Join Date
    Mar 2009

    Default Ageing of Bonaparte's Gull


    I would be interested in any views of the age of the Glamorgan Bonaparte's Gull. I assumed it was an adult but on looking at close-ups of the photos on Birdguides it appears to have some small black marks on the outer primary coverts and a black streak on what appears to be the outer web of P9. According to Gulls (Olsen and Larsson) these are featues seen in 2w.

    Regards, Graham

  2. #2
    Join Date
    Mar 2008


    Certainly looks as if 2nd-win is a possibility, but as usual there are complications. Kalev Rattiste gave a talk at recent gull conference at Peterhead in which he showed photos of Common Gulls with dark markings on their alula/primary coverts. None of these birds were however immatures and all were well into adulthood with one bird something like 20 years old (all birds ringed and of known age). I believe he suggested these markings were fake signs of immaturity, which are useful when attracting a mating partner! Perhaps the same applies to Bonaparte's Gull, and also Black-headed Gull? Second-winter Black-headed Gulls can often be picked out by more orangey legs/bill as well the black primary outer webs (attached), but I also have photos of birds which appear adult in every way except the black primary markings.
    Attached Images Attached Images

  3. #3
    Senior Member
    Join Date
    Aug 2008


    Old birds trying to look young and virile??

    Sounds just like humans!!

  4. #4
    Senior Member JanJ's Avatar
    Join Date
    Jan 2008


    Black markings on primary coverts - not nessecarily a sign of immature plumage in gulls, barabensis shows this and some Asian gulls as well. LBBG of known high age can have dark primary covert markings. I had a very good link showing many LBBG's with dark markings on primary coverts. I will try to find it.



Similar Threads

  1. Ageing Herring Gulls
    By adriaens in forum Advanced Bird Identification Q&A
    Replies: 16
    Last Post: December 11th, 2011, 08:44 PM
  2. Ageing Grey Phalarope...
    By XavierVandevyvre in forum Beginner Bird Identification Q&A
    Replies: 1
    Last Post: December 2nd, 2009, 12:00 PM
  3. Herring Gull Ageing
    By michael23 in forum Seabirds
    Replies: 5
    Last Post: May 26th, 2009, 07:01 AM
  4. Cheddar Bonaparte's Gull
    By Bobolink44 in forum Britain and Ireland Rare Birds
    Replies: 4
    Last Post: April 3rd, 2008, 06:36 AM
  5. Bonaparte’s Gulls on the Niagara River
    By in forum Birding Blogs
    Replies: 0
    Last Post: December 9th, 2007, 01:54 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts