Add new items to Plumage Season Observation Field

This came in as a feature request but I moved it to #general because observation fields are made by community members and not something that staff edit.

Annotations are sort of “official” observation fields, and can be discussed here:

You can search to see who has created an observation field at this page: for example a search for plumage finds this field for plumage season: which indicates @uheise created the field. You can send them a message or leave a comment at the bottom of that page requesting changes to the field.