But all three of those organizations are represented there.
IOC though has several distinct differences in species recognized versus NACC. For instance, the Fox Sparrows and Yellow-rumped Warblers are split in IOC, but still lumped as single species each by NACC.
So a merger of all of these checklists is GOING to result in some authorities being followed while others are not. Here's hoping they don't lump the Yellow-rumped Warbler, since I think NACC was pretty wrong on that decision.