Group names
I have been thinking about this a couple of days, and in the context of a field guide (as opposed to a taxonomic work) there can be an argument for showing the subspecies that seems most typical of the field identifiable group in question, and somehow it then feels wrong if the name of that subspecies does not appear next to the image. In a context with lots of room for text there could then be a text that the overall group would get a different group name, but the version of the Sibley guide I know (the big one) does not exactly have a lot of text.
Therefore, I would argue that there should be some liberty when we are talking about a field guide!
I admit that I've wondered whether I'm being overly defensive - worrying about the informal scientific naming of subspecies groupings after the most characteristic/widespread/well-known member, rather than the most senior member (following the rules of nomenclature).
But I feel that we risk unnecessarily creating a potential minefield for future generations (for no obvious advantage). In particular, it seems that Cornell's casually-applied group names are gaining traction, given the widespread usage of the
Clements Checklist (and perhaps could even be endorsed in a future edition of a highly-respected field guide...?). So popular birding literature, bird reports/records, photo captions, etc will inevitably become more and more littered with references to
apparently scientifically-named groups which give a completely misleading impression of their geographic scope (ie, technically excluding all more-senior taxa).
It would be a great pity if 100 years hence, students were forced to treat all early-21st century references to subspecific taxonomic groupings with extreme caution, as rules of priority were known to be habitually disregarded by significant authorities during that era!
And yet now (with the wealth of web-based resources) it's so much easier than ever before to identify the senior member of a subspecies grouping for naming purposes. [eg, it should be possible to correct the group names in the entire
Clements Checklist in a few days.]
On balance, it's probably preferable to stick to non-scientific (geographic or descriptive) names for subspecies groups rather than nomenclaturally-unsound pseudo-scientific names.