I am wondering what determines which observations are changed to what species in a taxon split? The recent split of the Yellow Warbler into 2 species– Northern Yellow Warbler and Mangrove Yellow Warbler– sparked my curiosity on this. I have 12 observations that WERE of Yellow Warblers. After the split, ALL of the IDs on 3 of the observations were changed to Northern Yellow Warbler and show evidence of taxon split. But all of the IDs on the other 9 were changed to Mangrove Yellow Warbler and have no mention of the taxon split. (I have attached images of both, each of which were taken at the Sand Dunes in Indiana, so all should be Northern, not Mangrove)
Just curious on what factors go into these. Thanks!

