tional input sampling event data (i.e.
checklists) file, required if you intend to zero-fill the data to produce a
presence-absence data set. This file consists of just effort information
for every eBird checklist. Any species not appearing in the EBD for a given
checklist is implicitly considered to have a count of 0. This file should
be downloaded at the same time as the basic dataset to ensure they are in
sync. If file is not found as specified, it will be looked for in the
directory specified by the <co