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Saltmarsh and Nelson's Sparrows (3 Viewers)

Peter Kovalik

Peter Kovalik

Well-known member
Slovakia
Jennifer Walsh, Adrienne I. Kovach, Oksana P. Lane, Kathleen M. O'Brien, and Kimberly J. Babbitt, 2011. Genetic Barcode RFLP Analysis of the Nelson's and Saltmarsh Sparrow Hybrid Zone. The Wilson Journal of Ornithology, Volume 123 Issue 2 pg(s) 316–322.
Abstract
 
Saltmarsh Sparrow

Walsh, Kovach, Babbitt & O'Brien (in press). Fine-scale population structure and asymmetrical dispersal in an obligate salt marsh passerine, the Saltmarsh Sparrow (Ammodramus caudacutus). Auk.

PS. Hmm, it was posted on JSTOR (honest!), but seems to have been withdrawn for now...
 
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Saltmarsh Sparrow

Richard Klim said:
Walsh, Kovach, Babbitt & O'Brien (in press). Fine-scale population structure and asymmetrical dispersal in an obligate salt marsh passerine, the Saltmarsh Sparrow (Ammodramus caudacutus). Auk.

PS. Hmm, it was posted on JSTOR (honest!), but seems to have been withdrawn for now...
Click to expand...
It's back. I wasn't just seeing things! [abstract]
 
Kovach et al 2015

Kovach, Walsh, Ramsdell & Thomas (in press). Development of diagnostic microsatellite markers from whole-genome sequences of Ammodramus sparrows for assessing admixture in a hybrid zone. Ecol Evol. [abstract] [pdf]

Walsh et al 2011. Wilson J Ornithol 123(2): 316–322. [pdf]
Walsh et al 2012. Auk 129(2): 247–258. [pdf]
 
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Hybridisation

Walsh, Shriver, Olsen, O'Brien & Kovach 2015. Relationship of phenotypic variation and genetic admixture in the Saltmarsh–Nelson's sparrow hybrid zone. Auk 132(3): 704–716. [abstract] [pdf]
 
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lewis20126 said:
Disappointing for those of use who have only recorded both taxa on the wintering grounds (Florida and Texas in my case)! I'm not taking them off though ;)
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I think I'm safe with wintering (interior) Nelson's at Rollover (TX) and breeding Saltmarsh at Hammonasset Beach (CT). But my records of Saltmarsh at Plum Island (MA), and both Saltmarsh and 'Acadian' (Nelson's) at Scarborough Marsh (ME) are probably a bit dodgy... ;)
 
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The study only took place in the small area of overlap; both species range over a much wider area. Nelson's Sparrows (nominate) are easy to distinguish, and don't look like birds from the area of overlap (subviragtus and nominate caudacutus) . Likewise, the southern breeding Saltmarsh Sparrows (diversus) are more streaked and different than birds from the two taxa that are hybridizing. In areas of overlap in winter (Atlantic Coast), a huge majority (likely 99+%) of the birds will be pure, and it will easy to differentiate if they are diversus or nelsoni.

Andy
 
Population trends

Shriver, O'Brien, Ducey & Hodgman (in press). Population abundance and trends of Saltmarsh (Ammodramus caudacutus) and Nelson's (A. nelsoni) Sparrows: influence of sea levels and precipitation. J Ornithol. [abstract]
 
Kratter said:
The study only took place in the small area of overlap; both species range over a much wider area.
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I might add that the methods of the Walsh et al. paper suggest that there was no objective documentation (no photos, and certainly no voucher specimens) taken of the individuals captured and bled for genetic comparisons! So how certain can we be that these were accurately scored and identified?
 
DLane said:
I might add that the methods of the Walsh et al. paper suggest that there was no objective documentation (no photos, and certainly no voucher specimens) taken of the individuals captured and bled for genetic comparisons! So how certain can we be that these were accurately scored and identified?
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Trusting the results of the published peer reviewed research of colleagues, over assuming they made it all up?

It would of course be better for Genbank and similar to allow photos to be linked and for this to be done.
 
thomasdonegan said:
Trusting the results of the published peer reviewed research of colleagues, over assuming they made it all up?
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I don't think that wanting to see the data on which a study is based is exactly unusual, nor that 'assuming they made it all up' is the only alternative. If this were the case, why would any published paper even bother to include a section on methodology?
 
thomasdonegan said:
Trusting the results of the published peer reviewed research of colleagues, over assuming they made it all up?
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Mostly pointing out that they weren't making an effort to correct for human error. And let's face it, human error happens to us all. But such results are based on the fundamental understanding that the researchers are competently identifying and scoring their subjects. Having documentation that would allow others to assess this and also do so independently (i.e., do science) is pretty important, no?
 
DLane said:
Mostly pointing out that they weren't making an effort to correct for human error. And let's face it, human error happens to us all. But such results are based on the fundamental understanding that the researchers are competently identifying and scoring their subjects. Having documentation that would allow others to assess this and also do so independently (i.e., do science) is pretty important, no?
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Sure (as in the bit of mine not copied from above). The question is how far this need for documentation goes. If you do an ecological study of clutch size, do you want to see specimens of all the young birds that were found to prove they really existed and were correctly identified? This study is more one where morphology would better be documented, but you know what I mean. It's also not unheard of to put in private requests for raw data to verify - the documentation of methods does not have to be in the paper itself.
 
thomasdonegan said:
Sure (as in the bit of mine not copied from above). The question is how far this need for documentation goes. If you do an ecological study of clutch size, do you want to see specimens of all the young birds that were found to prove they really existed and were correctly identified?
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Yes Thomas, I think every study should document everything with specimens all the time. Your example isn't reducto ad absurdium at all. Sarcasm aside, mentioning in the methods section that the plumages of the birds scored were also documented by at least digital photos would have been easy. The lack of such a statement suggests that it wasn't done. Thus, my confidence in the scoring process is relatively low... particularly because it is not repeatable. Something like this could easily have happened 20 years ago without much comment, but in today's world of cheap digital cameras, it seems a major oversight. Generally speaking, using genetic samples that are unvouchered in any way is careless at best, and probably will result in the publication not turning many heads in the systematics community.

If folks here think (as some above comments suggest) that the AOU would use this study as a basis to merge the two species again, my intent is to point out that there are weaknesses in the design of the study that would probably keep the AOU from acting on it, and rightly so. But Dr. Kratter would probably have better intuition on this than I.
 
DLane said:
. Thus, my confidence in the scoring process is relatively low... particularly because it is not repeatable. I.
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Dan

How is a deposited vocal recording 123 of Scytalopus sp, specimen no, XYZ going to be repeatable? Am I supposed to take on trust that specimen No XYZ did indeed make the vocals attributed to it in recording 123. How is that repeatable at the level of the individual?

If you then argue this could be replicated by sampling the population, then that is surely the same as a repeat of the Sparrow study, using different individuals?

cheers, alan
 
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