When the CV has confidently mis-learned a species

[upupa-epops]

Geography is one of those ID factors where there’s a range of possibilities and so you’re working with probability. As opposed to actual distinctive features where it’s binary; yes it’s that species because it has that mark, otherwise it’s not (outside of the possibility of a coincidental mutation, but the chances of that are negligible). With some taxa there’s more uncertainty about geography and so that also needs to be incorporated into your probability calculations. We know pretty well what the ranges of difficult gull species are, but we’re much less sure about millipedes. It’s possible for a European Herring Gull to show up in New York, and I’m sure it’s happened at some point, but neither a new birder nor the iNat CV should be concerning themselves with that possibility when they might be struggling enough with separating American Herring from Ring-billed.