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Understanding Subspecies in eBird

Most species names in eBird are easily found with a glance at your field guide, but eBird also allows entry of a number of other birds (sometimes we call them 'taxa') whose names do not appear in any guides. These break down into three main groups: hybrids, spuhs, and subspecies groups. Hybrids all have the word "hybrid" in the name (e.g., Mallard x Gadwall (hybrid)) and all spuhs either have a "sp." (e.g., scoter sp.) or slash (e.g., Greater/Lesser Scaup) in the name. The subspecies groups, such as "Herring Gull (American)", are more complicated and explained in this article.

Where do the eBird names come from?

Before we dive in to what a subspecies group is, it is important to understand where the eBird names come from. The species names within eBird, both the English name and the scientific name, come directly from recognized authorities. The bird names that we use in eBird are agreed upon by the North American and South American Classification Committees of the American Ornithologists' Union in charge of naming birds and defining which ones represent species. For bird names not treated by those two North American Committees, we defer to the Clements checklist. However, the hybrids and spuhs are uniquely defined for eBird. The subspecies groups are in almost all cases defined cooperatively by eBird and the Clements Checklist. More detail on the latest version of the eBird taxonomy can be found here.

Can you explain the scientific names?

Every organism on earth has a scientific name, sometimes called a Latin name since these names are often derived from Latin and follow a latinate structure. (We usually italicize scientific names.) This name includes both a Genus, which may be applied to several species (e.g., Junco), and a species (e.g., hyemalis). The two names together describe a species (e.g., Junco hyemalis). Furthermore, a subspecies name may be added for a three-word name that describes a subspecies, which is a distinctive form within a species that interbreeds (more or less) freely with other members of the species. So, Junco hyemalis carolinensis describes the southern Appalachian subspecies of Dark-eyed Junco. 

Within eBird it is possible to go to My eBird Preferences (under the My eBird tab) and change your view to show either eBird Common Names, eBird Scientific Names, or both.

What is a subspecies group?

Within eBird, a subspecies group is a taxonomic unit within a recognized eBird species; thus, by definition, any species that is divided into groups has at least two distinct forms and maybe more. Many of these subspecies groups may represent potential "splits" in the future (i.e., they may one day be considered species) and most of them can be identified in the field with experience. In some cases, the subspecies groups are more different from one another than there are from a similar species!

Subspecies groups in eBird are all given unique common names composed of the full species name with the group name in parentheses. In most cases, one could refer to the subspecies group by replacing the first part of the name with the parenthetical one. Thus, birders often refer to eBird's "Yellow-rumped Warbler (Myrtle)" as simply "Myrtle Warbler". We have tried to use recognized names for these groups whenever possible, but some of the name choices are descriptive (often geographic) names that we are using here for the first time.

Each subspecies group is further defined by its scientific name, which can be used to research more information about the subspecies. A subspecies group in eBird may include a single subspecies, specified by its full scientific name:

     Junco hyemalis aikeni, Dark-eyed Junco (White-winged)

two subspecies, which we indicate with a slash:

     Junco hyemalis hyemalis/carolinensis, Dark-eyed Junco (Slate-colored)

or a group of subspecies, such as:

     Junco hyemalis [oreganus Group], Dark-eyed Junco (Oregon)

In this last case, we do not specify all 7 subspecies that comprise Oregon Junco, so we describe it as the "oreganus Group". If you are interested in knowing the exact subspecies included within the group, or the range occupied by each subspecies, you can get that information from the downloadable Clements checklist.

Why does eBird include these groups?

At eBird we believe it is important to allow birders to collect as much information as specifically as possible. Many birders across the country routinely identify Myrtle Warblers and Audubon's Warblers, Western Palm Warblers and Yellow Palm Warblers, Harlan's Red-tailed Hawks, Scopoli's Cory's Shearwaters, and even Type IV Red Crossbills. For this reason, we try to allow this possibility for those that feel comfortable making these identifications. If you are not comfortable, or do not understand what the subspecies group refers to, please enter your sightings at the species level.

Since some subspecies groups are rather obscure or rarely encountered, we may not show every possibility on the regional eBird lists. Please remember that you can always seek these out using the "Add a species" box which is available after you click "Rare species" during checklist entry.

When we do include a subspecies, in general we try always to include the "parent species" on the checklist as well, so that you can report "Dark-eyed Junco" or "Dark-eyed Junco (Slate-colored)", depending on which you feel more comfortable with. However, since the regional checklists are developed separately by a large cadre of volunteers, each region may deal with subspecies groups slightly differently.

A final benefit for entering subspecies groups is that if they are ever split, we will automatically update your lists as appropriate. If you live in Texas, where Yellow-rumped Warblers could be either Myrtle or Audubon's, what will happen when they are split? Any sighting you enter as "Yellow-rumped Warbler (Myrtle)" will be moved to the new species "Myrtle Warbler" (likewise for Audubon's), but any sighting you entered as just "Yellow-rumped Warbler" would become a spuh: Myrtle/Audubon's Warbler. Since spuhs don't count on our bird lists, most of us don't want this to happen! (You will always have the option of changing your reports to reflect the subspecies, if you know which one it was but didn't specify in your original entry.)

Can we see data summaries for these subspecies?

Currently, an eBird map or bar chart of "Dark-eyed Junco" includes all subspecies groups and it is not possible to see a map for just "White-winged Junco" or "Slate-colored Junco." However, once we have collected enough information on subspecies we will make it possible to see a map of the entire species (Dark-eyed Junco) or any of the subspecies groups.

In the meantime, the subspecies information is stored in the database and is made available to scientists and others that request eBird data. Sometime soon we will allow the option to explore this data as well, but for now, the subspecies are used so inconsistently that the visualizations would not be meaningful. The subspecies you report are also always available via your own species summaries and list views within My eBird.

So, what IS "Herring Gull (American)"?

We would be remiss if we didn't explain the title of the article! Currently, Herring Gull (Larus argentatus) is a wide-ranging circumpolar species (in other words, occurs primarily in North America, Europe, and Asia). It includes four subspecies which eBird separates out as three groups:

  • Larus argentatus smithsonianus, Herring Gull (American)
  • Larus argentatus vegae, Herring Gull (Vega)
  • Larus argentatus argentatus/argenteus, Herring Gull (European)

Across most of the United States and Canada, the first subspecies Larus argentatus smithsonianus is the only expected subspecies Group that eBirders will encounter. Thus, you may see "Herring Gull (American)" on a number of eBird checklists.

However, in western Alaska (Aleutians, Pribilofs, and areas on the Seward Peninsula such as Nome), Larus argentatus vegae becomes more likely (see photo). A few Vega Gulls have been identified southward to Washington, California, and possibly as far east as Texas and Maryland. We obviously want to keep track of these sightings within eBird as much as possible.

Also, "European Herring Gull" is a rare visitor to Atlantic Canada (especially St. John's, Newfoundland) and has been increasingly sought and identified southwards along the Atlantic Coast. Although many of the records are still being reviewed by experts, photographs support sightings in Massachusetts, Maryland, and Florida, and possibly elsewhere as well.

Although these three groups are VERY difficult to tell apart, many of the recognized gull experts consider these three groups to comprise different species. For this reason in particular, "Herring Gull (American)" is popular on eBird checklists. If and when the species are split, it will be easy to convert all "Herring Gull (American)" sightings to the new species. But for now, we continue to track the subspecies groups within Herring Gull, for those that dare to identify them, on the hope that we will have a better understanding of their distribution whether they are split or not.

And the same is true for any subspecies group within eBird. We encourage you to try to learn more about the eBird subspecies groups in your area and identify them when possible.
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