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Message: <blockquote data-quote="Roy'N" data-source="post: 1938308" data-attributes="member: 11831">Sure but with overlap of about 80-90% in all 3 measurements it becomes useless in everything but the extremes. Under what theory are measurements with an overlap like that 'statistically significant' to the level that they are an argument for different species? It's fine when there are other strong arguments (like in the tapaculos Thomas Donegan has worked with) but if I understand this right there aren't yet for the crossbills. The voices are perhaps learned in them and the describers mention that they have observed voice shifts. If this is the case the breeding behavior can change. A crossbill with medium measurements could be one 'species' in one years. Shift voice and be another 'species' in another year. The genetic difference they reported in the description of the new crossbill is not impressive. Perhaps the South Hills Crossbill is a species but to my eyes evidence that can't be questioned is presently missing.This is about birds and the established requirements for taxonomy of other groups are often different and this make them irrelevant to the discussion. The possibility of asexual reproduction in plants alone make any direct comparison with birds impossible.</blockquote>