While most eBirders associate “Taxonomy Time” with October, the eBird team begins their preparations behind the scenes in July to ensure your eBird checklists stay current with the latest species splits, lumps, name changes, and more.
Some of the exciting taxonomic changes you can expect in October include a 7-way split of House Wren, a 3-way split of Barn Owl, 4-way split of Herring Gull, and the “lumping” (or rather, re-lumping) of Common, Hoary, and Lesser Redpoll into the singular Redpoll.
Beginning in late August, you may start to notice some of your eBird records beginning to change, usually from a species-level entry to a subspecies group. This is no cause for alarm: it is an essential part of the process. For example, you might notice Herring Gulls changing to “Herring Gull (European)”, “Herring Gull (American)”, or “Herring Gull (Vega)” or Rock Martins changing to “Rock Martin (Pale Crag Martin)”. These changes presage the species-level splits that are coming.
Introducing Scopoli’s Shearwater
One tricky split that could impact your eBird Life List is the division of Cory’s Shearwater (Calonectris borealis) and Scopoli’s Shearwater (Calonectris diomedea).
Historically, Cory’s Shearwater (Calonectris diomedea) had two recognized subspecies; C. d. borealis and C. d. diomedea (AKA Scopoli’s Shearwater). These subspecies overlap across much of their ranges, with Scopoli’s breeding primarily on Mediterranean islands and borealis breeding primarily on islands in the East Atlantic.
Scopoli’s tends to be smaller and more slender. But the key field mark is that it has more white in the underwing, with white “webbing” on the outermost primaries extending towards the wing tips (20% or more of the outermost primary tends to be white in Scopoli’s).
Based on differences in DNA, vocalizations, and the lack of hybridization, Calonectris borealis (Cory’s Shearwater) and Calonectris diomedea (Scopoli’s Shearwater) are now recognized as separate species. Beware of a tricky switcheroo: Calonectris diomedea will now refer to Scopoli’s Shearwater, while the “new” Cory’s Shearwater switches to C. borealis.
Impact on your eBird Life List
Your past observations of “Cory’s Shearwater (Scopoli’s)” will automatically update to Scopoli’s Shearwater, adding a new species to your Life List if you have reported both forms. Hooray!
Your past observations of “Cory’s Shearwater (borealis)” will update to Cory’s Shearwater with no subspecies designation.
However, since the two species cannot be reliably differentiated by range, existing reports of Cory’s Shearwater without a subspecies designation will be updated to “Cory’s/Scopoli’s Shearwater”. See which of your observations will become Cory’s/Scopoli’s Shearwater.
To retain Cory’s Shearwater on your Life List, you must have at least one observation of Cory’s Shearwater (borealis).
For any of your eBird checklists in the Atlantic Ocean that report “Cory’s Shearwater” without a subspecies: if you are confident that at least one individual was the borealis subspecies based on past field notes or photos*, add “Cory’s Shearwater (borealis)” to your list with a count of X individuals (‘X’ indicates the species was present, but the exact count is unknown).
For checklists where you are certain all individuals reported as “Cory’s Shearwater” were the borealis subspecies*, use the “Change Species” button to update the entire observation to “Cory’s Shearwater (borealis)” instead. And if you have photos, please upload them and try your best to identify them correctly.
* While Cory’s Shearwater tends to be more common than Scopoli’s along the east coast of North America and the western coasts of Europe and Africa, neither species should be assumed based on location alone.
And if you’ve never observed any Cory’s Shearwater, you have the easiest job of all. Just relax and stay tuned for additional information as we prepare the eBird database for this year’s exciting batch of taxonomic changes. Happy birding!