Add filter for observations with only original ID

[kzoebel]

@grampianshiker

I wonder what the difference is.

I imagine it depends on the number and interests of the identifiers in each of our areas. Your area might have more identifiers looking at plants. Or maybe the types of plants in each of our areas has more dedicated identifiers? Like wildflowers versus trees versus mosses, etc. It’s really fascinating to think of all the different types and combinations of variables.