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Message: <blockquote data-quote="njlarsen" data-source="post: 1938304" data-attributes="member: 7427">In all fairness, the data presented in the above post included some examples, such as :With these differences, it would be more than half of the birds that would not be diagnosable by bill depth (I think). In the monograph on subspecies that we had a long thread about earlier, one or more of the authors argued that if two populations differ by some few percent in one average measure, then you just had to increase the sample size enough and you would end up with a significant statistical difference that would not be biologically meaningful. As I understand it, that is the cause for the statistics called diagnisability which basically measures how large a percentage of the population cannot be id'ed to that population by whatever measure is used. However, I do agree that the most important thing is to look at whether the birds themselves think that another bird belongs to the same species or not; the problem is to be able to ask the birds that question and be able to understand the answer <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />Niels</blockquote>