Pedrambirder
Well-known member
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Which Warbler? Iran, Khorasan-e Razavi, May 2022 (1 Viewer)
- Thread starter Pedrambirder
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Pedrambirder
Well-known member
Thank you.
KenM
Well-known member
Am unsure how this could “safely” be ascribed to BRW?
At best, the primaries are 3/4 of overlying tertials (Blyth’s should be 50%), the emargination on p3 is barely in alignment with the last underlying tertial, should be further down the wing surely?
I think safer to be ascribed to RW imho.
Cheers
Last edited:
kuzeycem
Medicinal Birding
Pp looks at most %50 to me. Emarginations fit Blyth's; p3 before the tertial tips, p4 more or less in line.
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Blyth's Reed Warbler by Peter Garrity
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KenM
Well-known member
Having measured all three images, I’m still finding the “more or less” 2-3 ratio regarding pp-tertials.Pp looks at most %50 to me. Emarginations fit Blyth's; p3 before the tertial tips, p4 more or less in line.
Blyth's Reed Warbler by Peter Garrity
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Allowing for a degree of elasticity with the alignment of the emarginations within the tertial area, it does appear that image one does show the emargs. to fall within tertial three, however less so in the other two images?
In image one, I find your marker points to appear slightly exaggerated towards the tertial length, ie taking the line to include the secondaries within the tertial bunching, also a “generous” base start point for tertial one?
Clearly, with that level of difference in the interpretation, we’re never going to agree!
Substantially over 50% when measured from your own markings. Thus, not related to 'eyesight' or 'misunderstanding of feather tracts'.
kuzeycem
Medicinal Birding
Well then lucky me the upcoming guidebook has some very convenient preview pages, I don't know Dutch but pretty sure <%80 is universal, hope I'm 'interpreting' correctly.
Out of interest, how much exactly is this "substantially over 50%" measurement? I only have my phone with me at the moment.
Out of interest, how much exactly is this "substantially over 50%" measurement? I only have my phone with me at the moment.
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lou salomon
the birdonist
my measuring of pp is 55-58% which is not substantially over 50%. and Blyth's is supposed to have around 60%, so, that's perfectly in line (as opposed to fuscus Reed and Marsh).
Plenty of statisticians and Brexit-voters would disagree. But subjective, of course. As a working definition of 'substantially' (because it works here), how about 'obviously, without measuring it' - especially when it's in contrast to 'at most %50', which is clearly wrong for this bird.
lou salomon
the birdonist
but we're talking about the 3 very similar looking brown job Acrocephalus, not about those easily recognizable, so among scirpaceus, palustris and dumetorum, the latter certainly is the only one with a pp this short (that said, I've once photographed a scirpaceus with around 60%...).
Not as far as I know but they do pass through on their way to their breeding grounds in Central Asia and Siberia from late April to mid-May.Genuinely sorry that i cant contribute to the feather-fiddling - one day!
What is the situation of BRW in Iran? Regular passage migrant? They dont breed do they?..
TIA.
I'd also go for Blyth's Reed. Apart from the short primary projection, it has a weak loral stripe compared to Eurasian Reed but "bulging" lores. Typically plain and rather sleek wing, with even flight feathers and lacking contrasting centres to the tertials and pale tips to the primaries I'd expect to see in Eurasian Reed. Lacking rufous tone to the rump of Eurasian Reed - upper parts concolorous.
What is the length of P1 on Eurasian Reed? I think in the 2nd image you can just about see the typical stunted little P1 of Blyth's Reed, partially hidden under the primary coverts. I don't know if P1 is longer in Eurasian Reed.
What is the length of P1 on Eurasian Reed? I think in the 2nd image you can just about see the typical stunted little P1 of Blyth's Reed, partially hidden under the primary coverts. I don't know if P1 is longer in Eurasian Reed.
Grahame Walbridge
Well-known member
Guys, the thing about pp is that it is a variable, like all biometrics, but crucially, pp of BRW averages shorter than ERW. The OP has a pp of c60% (in line with Lou's estimation) so about mid-range for BRW. It is not anywhere close to 75%! Andy, length of P1 is virtually the same range for both species and so not significant in differentiation between species.
The bird has emarginated P3, P4, roughly level with tips of T2 and T3 respectively which is significant. A few fuscus from the Middle East can show a weak emarginated P4 but in these instances would be closer to the feather tip i.e likely to fall well beyond tip of T3.
Based on a combination of wing structure, bill and loral pattern, in particular, I would not hesitate to call it a Blyth's.
According to Khaleghizadeh et al (2017) its an uncommon passage migrant in Iran, mainly in the east of the country so, location in the NE is perfectly OK.
Grahame
The bird has emarginated P3, P4, roughly level with tips of T2 and T3 respectively which is significant. A few fuscus from the Middle East can show a weak emarginated P4 but in these instances would be closer to the feather tip i.e likely to fall well beyond tip of T3.
Based on a combination of wing structure, bill and loral pattern, in particular, I would not hesitate to call it a Blyth's.
According to Khaleghizadeh et al (2017) its an uncommon passage migrant in Iran, mainly in the east of the country so, location in the NE is perfectly OK.
Grahame
KenM
Well-known member
Yes, apologies all round!, I misconstrued my percentages and yet acknowledged the correct 2-3 ratio in post 6!
Thus having re-measured all three images, I’m now finding c65% for pp which would be at the upper end for BRW, I can recall a colleague mentioning that anything longer gets into RW/MW territory and to compound it, I’ve seen just the one BRW properly and that had a 50% pp projection….very short by comparison to Pedram’s bird.
As an aside, what is the take on this bird, accepting that the images are not as good as Pedram’s?
Cheers
Thus having re-measured all three images, I’m now finding c65% for pp which would be at the upper end for BRW, I can recall a colleague mentioning that anything longer gets into RW/MW territory and to compound it, I’ve seen just the one BRW properly and that had a 50% pp projection….very short by comparison to Pedram’s bird.
As an aside, what is the take on this bird, accepting that the images are not as good as Pedram’s?
Cheers
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Location? Date?
KenM
Well-known member
Remiss of me, May’19, London.
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