I would add to Zac's reply that the filters cover counties as a whole, and so if a species is uncommon or difficult to ID in one part of the county during a particular season, but common in another part, the filter might be set to identify potential errors based on that part of the county where errors might occur.
For example, in the Champlain Valley shorebirds common by Lake Champlain during fall, let's say, might also occur at high elevations rarely, but with a relatively high frequency of mistaken IDs. The filter could be set to catch those errors, meaning that birders reporting the birds from the shores of Lake Champlain will have the same flagging. The reviewer simply confirms those without ado. It is not possible in eBird to have separate filters within counties like ours, such as one for lakes and wetlands, one for lowlands, one for highlands, and one for tundra. The filters, however, are finely tuned to the changes in seasons.
If you are curious about a filter setting, contact the local reviewer.
Good birding and safe health.
Ian --------------------------- Reviewing Addison, Chittenden, Grand Isle, and Franklin Counties
. On 6/29/2020 9:38 PM, Zacheriah Cota-Weaver wrote: > Ruth, > > All of the local eBird reviewers set their own filters based on county > levels. These filters allow reviewers to catch eBird observations that have > potential for data errors, such as rare or easily misidentified species. > The eBird needs alerts and rare bird alerts are based on observations > flagged by these filters. When you see common species showing up on these > lists, it is likely that a birder chose to report a subspecies that > triggered one of the filters. Most eBird reviewers have subspecies flagged > to ensure the proper written description or evidence is provided when > identifications are made to that taxonomic level. > > Below I've linked an article about the review process that might help > further answer your question. It's one that I'm sure other eBirders have > had as well. Cheers! > > Zac Cota > Washington County eBird Reviewer > > https://support.ebird.org/en/support/solutions/articles/48000795278-the-ebird-review-process > > On Mon, Jun 29, 2020 at 9:27 PM R Stewart <2cnewbirds...> wrote: > >> Can someone please inform why certain very common birds keep showing up on >> the Rare Bird Alert - such as Am Robin, (migratorius Group) , House Wren, >> Turkey Vulture, Common Yellowthroat, Barn Swallow, Song Sparrow, etc? >> AND why a Yellow-billed Cuckoo seen up N. is on the list and not the YBCU >> reported in the southern 'sun belt?" >> >> -- >> Ruth Stewart >> E. Dorset VT >> >