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Message: <blockquote data-quote="thomasdonegan" data-source="post: 1935006" data-attributes="member: 5190">I have read all these papers.Let's look at the Condor "new species" description from last year.Diagnosis: "Very similar to other Red Crossbills in North America but larger (body mass and bill depth, but upper mandible relatively short) on average than other Red Crossbills currently found commonly north of Mexico (Table 1) and with distinctive vocalizations (see below; Smith and Benkman 2007). As in other Red Crossbills, males are reddish in body coloration whereas females are greenish-gray and smaller than males (Table 1; see below)."Conclusion:Voice - different, but see above discussion.Plumage - the same.Biometrics - "average differences" - i.e. not diagnosable.  If you look at the table of biometric data in the paper, you can see some highly unimpressive divergence in biometrics.  Data on range of measurements for males for the variables mentioned in the species diagnosis section is below:Mass: Type 2 28.8–38.6 Type 5 28.6–38.6 New species 29.2–39.4Bill depth:Type 2: 8.97–10.38 Type 5: 8.77–10.14 New species: 9.05–10.56Bill length from nostril:Type 2: 13.79–18.87 Type 5: 13.95–16.87 New species: 13.40–17.30These are not diagnostic differences.  With enough data, one might be able to generate a positive t-test, showing statistically significant average differences, but based on these sorts of data you would expect at least 80-90% of individuals not to be capable of being identified based on biometrics.Which takes me back to the original posting.  If voice is all there is to go on in terms of real diagnosable differences, and this can shift, who is to say this is not a learned character?The paper states: "We found one instance of a female of call type 2 shifting its call to match that of its mate, a South Hills Crossbill, in successive years, but because this shift occurred only in the year following this pair’s successful breeding such call shifts should affect our estimates of the frequency of hybridization only minimally (Keenan and Benkman 2008; see also Summers et al. 2007)."  That is one possible interpretation but one could see people arguing for others in terms of delimiting species based on (i) actual observed hybridisation between "species"; and (ii) learning by one "species" of the other "species" voice.Going back again to the original posting, I do think this and other papers make up a fantastic piece of research but it seems a bit premature to be describing sympatric "species" without diagnosable differences except for in characters that may be learned.  AOU's NACC seemed to have a similar view.</blockquote>

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