Reviewers have tagged some checklists as "multi-party lists", which display this message at the top:
Multi-party checklist. This checklist has been flagged as a multi-party list. eBird only displays checklists that were collected by a single birding party. This checklist and its observations do not appear in public eBird outputs. More information.
Checklists that involve summed totals from two or more parties are flagged as Multi-party checklists and not showed in public eBird output.
If two or more birders split into two separate parties (not within easy shouting distance of one another) it is considered a multi-party checklist. An example might be two parties driving separately and covering different areas within a Christmas Bird Count territory or observers that split up to each cover one half of a lake. In both of these cases, the separate parties should submit separate eBird checklists.
Checklists that do not appear in public eBird output are also not used for science. To learn more please see our article on Multi-party checklists as well as Public and Non-public Checklists for more information on how checklists are displayed.