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Thread: Pied Flycatcher (presumed) Flamborough Head 28 April 20012

  1. #101
    Senior Member forktail's Avatar
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    But I thought the wing length was well out of range for male Iberian given by Svensson?

    Although again I should point out that the sample size used for the published measurements was very small, and where Svensson's figures of 75-79mm are actually from I am unaware. The earlier data of Curio (BWP) did, however, give an upper length of 83mm for males and females combined but without breakdown. So maybe Iberian is still on despite the initial announcement of Pied on DNA now being not the whole picture? Perhaps when identification papers are written or species are described in the current age, more should be made of the potential for error as these figures are subsequently quoted all over the place with caveats such as Brian's mention of small sample size being omitted. The greater covs of Atlas has been very instructive in this respect - gone from the average birder's idea of usually all white, to all white being hard to find, to now never all white! We live in interesting times...

    F
    Last edited by forktail; May 13th, 2012 at 05:33 PM.
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  2. #102
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    If the South Landing ficedula is just a Pied Flycatcher, I give up. In my opinion, I cannot see how it can be that species, despite what the science seems to be claiming. I did not see any Collared Flycatcher in it either, nor anything that suggested a hybrid. If Pied Flycatcher in first-summer male plumage can identically resemble both Iberian Pied and Atlas Pied in spring, then we are on a hiding to nothing and it is pointless ever trying to identify such birds out-of-range. It would suggest it is an impossible task.

    I am loathe to embark on this DNA trail of destruction - not really my sort of birding - but reports suggest it is far from infallible. Apparently individuals have been put inside for murder on evidence based on DNA only to be released at a later date after it was found that the 'perpertrator' was over 500 miles away at the time. Also, I am told that DNA between assorted varieties of homo sapiens have been found to differ by as much as 1% - a higher differentiation that what we are using to speciate some avian forms.

    The South Landing male was a pretty unique individual - staying at one site for the best part of two weeks - fairly typical of North African/Iberian vagrants in our country but virtually unheard of in a migrant Scandinavian/East European-bound Pieds. How this leaves Andrea's extralimital records, or those elsewhere in Mediterranean Europe this year, I do not know and I look forward to an identification paper highlighting the possibility that Atlas Pied Flycatcher can be easily confused with North European Pieds that take on exactly the same plumage traits. Perhaps it is just our fault - just like the redpoll cline, perhaps Pied Flycatcher is really nothing like as far diverged as yet

  3. #103
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    the GC seems and appear to be ALL WHITE, indeed.... but there was a long time of assuming that they were all white because there was a first sentence done by a great birder, and then everybody (inlcuding me)m for long time indeed thought to see them all white.... but indeed, they appear all white once the wing is closed because they central coverts, which cover and hide all the outermost coverts, indeed are fully white.... but once the wing is fully spread (hard in the skins) you will see the real pattern of the whole full set of GC (9 to 10 coverts in tot.)

    Please, wait for 1 or 2 month more and you will see in Birding World what I mean, I could not publish here all the materials....THANKS and sorry not to be more clear wiuth numbers vs percentage etc etc.

    Andrea

    anyhow a GREAT bird indeed, not for twitchers may be, but sure for birders and for who love to learn more and more and always have doubts abpout own belivings rather than list only

  4. #104
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    Quote Originally Posted by macrourus View Post
    the GC seems and appear to be ALL WHITE, indeed.... but there was a long time of assuming that they were all white because there was a first sentence done by a great birder, and then everybody (inlcuding me)m for long time indeed thought to see them all white.... but indeed, they appear all white once the wing is closed because they central coverts, which cover and hide all the outermost coverts, indeed are fully white.... but once the wing is fully spread (hard in the skins) you will see the real pattern of the whole full set of GC (9 to 10 coverts in tot.)

    Please, wait for 1 or 2 month more and you will see in Birding World what I mean, I could not publish here all the materials....THANKS and sorry not to be more clear wiuth numbers vs percentage etc etc.

    Andrea

    anyhow a GREAT bird indeed, not for twitchers may be, but sure for birders and for who love to learn more and more and always have doubts abpout own belivings rather than list only

    I agree, if we don't ask the questions, and just go with what we are told is the case, we do not learn anything. Looking forward to your article Andrea.

    And I agree a great bird, that I found more fun than many of the more obvious "ticks on the list" that I've seen over the years... I've had loads of fun reading up and learning with this one (and the Thayer's in Linc's). This is what makes birding fun for me!

    Steph'

  5. #105
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    Quote Originally Posted by forktail View Post
    But I thought the wing length was well out of range for male Iberian given by Svensson?

    Although again I should point out that the sample size used for the published measurements was very small, and where Svensson's figures of 75-79mm are actually from I am unaware. The earlier data of Curio (BWP) did, however, give an upper length of 83mm for males and females combined but without breakdown. So maybe Iberian is still on despite the initial announcement of Pied on DNA now being not the whole picture? Perhaps when identification papers are written or species are described in the current age, more should be made of the potential for error as these figures are subsequently quoted all over the place with caveats such as Brian's mention of small sample size being omitted. The greater covs of Atlas has been very instructive in this respect - gone from the average birder's idea of usually all white, to all white being hard to find, to now never all white! We live in interesting times...

    F

    I don't know where Lars got his data from, but I would be amazed if he hadn't measured birds himself and probably at Tring; there is a series there, after all (alternatively AMNH). Intelligent authors always give their sample sizes and, if they don't, intelligent editors should insist that they do... and make it clear whether they are taking measurements from specimens or live birds, relative numbers of males and females, where relevant, etc. After that, the rest is up to the reader.

    It's worth remembering too that there will also, always, be variation in mensural data through human error and measuring skills / methods. This is long known, but to give some examples, I have tested my own measuring skills (or lack of them) against several other people in recent times. Andrew Grieve regularly measures wings an extra c.1 mm than me. Hadoram and I usually get results within 0.5 mm (or less) of each other, and I think Lars consistently measures wings longer than either of us. None of that matters provided one person does the sampling, or you test the differences and take a mean.

    I don't know the relative differences in wing lengths between these Ficedula, or if indeed there truly are any, but if one person says "I measured the wing of a live bird and it was 56 mm and the books state that x species has a wing length of 58-64 mm, so the bird I trapped must be y not x", I would treat that very cautiously (to say the least). There are simply too many vagaries therein to base an argument.


    Guy M. Kirwan


  6. #106
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    Scroll down the link below. Check tabla 1 for wing lengths (media and deviation) of an iberiae population from central Spain, all breeding birds, 892 males and 1136 females.

    http://www.vertebradosibericos.org/a.../fichypid.html

  7. #107
    Senior Member mafting's Avatar
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    Quote Originally Posted by GMK View Post
    I don't know where Lars got his data from, but I would be amazed if he hadn't measured birds himself and probably at Tring; there is a series there, after all (alternatively AMNH).
    The Flamborough bird will have been measured as max chord, but wont Tring/museum birds have been measured as min chord (and so be shorter)? I think min chord is also common for Scandinavians?

  8. #108
    Senior Member mafting's Avatar
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    Quote Originally Posted by LeeEvans View Post
    The South Landing male was a pretty unique individual - staying at one site for the best part of two weeks - fairly typical of North African/Iberian vagrants in our country but virtually unheard of in a migrant Scandinavian/East European-bound Pieds.
    It might be significant that it also 'lost' two tail feathers. This does have an energetic cost to the bird, which might have influenced its decision about when to leave.

    But why assume it was heading east? Maybe it was a British bird heading north? Wheatears and Redstarts, presumably also heading north, have been hanging around in southern England for days this spring.

  9. #109
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    Quote Originally Posted by Motmot View Post
    Scroll down the link below. Check tabla 1 for wing lengths (media and deviation) of an iberiae population from central Spain, all breeding birds, 892 males and 1136 females.

    http://www.vertebradosibericos.org/a.../fichypid.html
    Hi Eduardo, hope all is well with you.

    To expand on your post, the wing length data are 78.3 mm +/- 2.1 mm for males (892) and on average shorter for females at 76.3 mm +/- 2.6 mm for females (1136). The Flam bird was measured at 83 mm, but with the proviso that we don't know how close to the true value that measurement is.

    F.
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  10. #110
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    I'm not in the least surprised.

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