Sunday, March 7, 2010

Comment on Comments

I have had some good comments posted bringing my attention to the occasional error in the blog. I certainly appreciate any comments or insights into any of the unanswered questions I raise. I had a interesting comment on the first part of  "The Does Size Matter?" post. I have no way of responding directly back to the individual so I thought I would respond in the Blog. The comment is below:

"It seems if you study a photo too hard you lose perspective. Your "big" Kumlien's Gull is certainly not that species - not even close. It is without doubt a Herring x Glaucous Gull. You must be aware that Glaucous Gull bill size has considerable variation among races, as well as sex. Your gull's bill is well within normal variation for Glaucous."


Response to Jake:


Glaucous Gull is indeed made up of various races or subspecies. The nominate subspecies Larus h. hyperboreous is the subspecies native to Canada with the nearest other subspecies being Larus h. barrovianus native to northern Alaska. I am aware of no other subspecies of Glaucous Gull other than the native nominate subspecies being recorded in Ontario. So I think "race" is not an issue. I fully agree that the bill size may well be in the range of Glaucous Gull. If you review the measurements in Olsen & Larrson their is overlap between male Kumlien's and female Glaucous in all but one of the bill measurements. The outlier was Bill Depth at Base with a less than 1mm difference. This is really my point that size and structure are very broad and overlapping even between Kumlien's and Glaucous Gulls.




Adult Kumlien's Gull- supersized


Adult Kumlien's Gull- supersized with open wings

My final determination of this bird as a Kumlien's Gull and not a Nelson's Gull is based on the primary pattern not size or structure. The primary pattern is near identical to Type e pattern of Kumlien's Gull Adults as described by Howell and Mactavish in 2003 and illustrated subsequently by Martin Elliot. This great aid to Kumlien's Gull identification is illustrated on page 252 of Howell and Dunn's - Gulls of the Americas. It strikes me as most unlikely that a Nelson's Gull would end up with a near perfect Kumlien's Gull primary pattern.


Wing close up showing Type e Adult Kumlien's Gull primary pattern

Although you state "your "big" Kumlien's Gull" is not that species- not even close"you fail to provide any rationale or explanation for your obvious certainty in this statement. If you are basing this on the size and structure of the bird I have clearly failed to make my point to you that this can be very misleading and is not definitive. 

I would be most interested in the rationale for your claim "that this is without a doubt a Herring x Glaucous Gull". I would be pleased to add the comments to this posting. If anyone else feels this is a Nelson's Gull I would be keen on hearing why and will add the comments to the Blog.

Kirk
Continue on for Part 2 of Does size Matter-Thayer's Gull


38 comments:

  1. 你的部落格很棒,我期待更新喔 ........................................

    ReplyDelete
  2. 培養健全孩子最好的方法是父母先成為健全的人。......................................................

    ReplyDelete
  3. 恨一個人,比原諒一個人,更傷力氣。......................................................

    ReplyDelete
  4. 真正的愛心,是照顧好自己的這顆心。.............................................

    ReplyDelete
  5. 這個讚唷!!值得佳賞與獎勵~~●ω●........................................

    ReplyDelete
  6. 向著星球長驅直進的人,反比踟躕在峽路上的人,更容易達到目的。.........................

    ReplyDelete
  7. 在你一無所有的時候 是誰在陪伴你 他便是你最重要的人 ............................................................

    ReplyDelete
  8. 人有兩眼一舌,是為了觀察倍於說話的緣故。............................................................

    ReplyDelete
  9. Say not all that you know, believe not all that you hear.............................................................

    ReplyDelete
  10. 量力而為,別勉強了,Cut your coat according to your cloth...................................................................

    ReplyDelete
  11. 世界上沒有本來就應該的事,因為老天爺也沒有劇本.......................................................

    ReplyDelete
  12. 人生是一連串的課程,必須活過才能明白。.......................................................

    ReplyDelete
  13. 每日都有新日光,每日都有新希望。..................................................

    ReplyDelete
  14. 人不能像動物一樣活著,而應該追求知識和美德............................................................

    ReplyDelete
  15. 打擾你實在不好意思, 你的blog很好看呢!!!!............................................................

    ReplyDelete
  16. 一個人的價值,應該看他貢獻了什麼,而不是他取得了什麼....................................................

    ReplyDelete
  17. 大肚能容,了卻人間多少事,滿腔歡喜,笑開天下古今愁。..................................................

    ReplyDelete
  18. 這麼好的部落格,以後看不到怎麼辦啊!!!............................................................

    ReplyDelete
  19. 凡事三思而行,跑得太快是會滑倒的。..................................................

    ReplyDelete
  20. 來看你了~心在、愛在、牽掛在,幸福才會繁衍不息^^...............................................................

    ReplyDelete
  21. 生命所經歷的折磨愈多,其所產生的奮鬥力愈大。................. ................................................

    ReplyDelete
  22. 這不過是滑一跤,並不是死掉而爬不起來了。..................................................

    ReplyDelete
  23. 與朋友在一起,分擔的痛苦是減半的痛苦,分享的快樂是加倍的快樂。......................................................................

    ReplyDelete